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N-Prize
There's plenty of room at the bottom at the top. | |
[UPDATE 10th April 2008. The N-Prize
has now been taken to the Real World,
and can be found at www.n-prize.com.
Please visit the site for the latest version
of the rules.
Many thanks to [Wagster] and all at
pictureandword for setting up the site,
and to Jutta for allowing
reciprocal
linking.
To avoid confusion to visitors from the
N-prize site, Maxwell Buchanan would
like to confess that he is actually mild-
mannered scientist Paul H. Dear]
I suspect similar ideas have been
proposed before, so I'll delete this if
people think it's not worth discussing.
Actually, it may even not be an invention,
except that the invention is a
competition.
The challenge is to put a payload of
between 9.99 and 19.99
grams (that's the weight of 2-4 quarters
or
1-2 £1 coins) into orbit (defined as being
able
to complete 99 orbits or more before
re-entry or loss) for a total cost of
£999.99 or
less.
This is the cost of the launch vehicle,
payload, fuel, and any ground-based
systems
needed to support it, but excludes
development or prototyping costs. The
satellite has to be detected from earth by
some means, sufficiently to confirm that
it has completed at least 99 orbits. The
cost of the detection is not part of
the £999.99, and outside help may be
recruited.
The orbit needn't be regular or stable - it
just has to get there and stay up for 99
orbits. Prize value is £9,999.99. Other
rules may be imposed entirely at the
whim of the organizers, to block any
loopholes which go against the spirit of
the challenge. Entrants are strongly
advised to contact the organisers before
and during development.
Entrants are entirely responsible for their
own safety and that of others.
Compliance or otherwise with relevant
regulations is entirely the responsibility
of the entrants, who will be liable for any
costs, legal penalties etc arising from
compliance or lack thereof. Any costs
incurred in the course of complying with
regulations (for example, permits, safety
inspections etc) will be considered part
of the cost of the project, and must
therefore fall within the £999.99 limit.
Any legal costs, fines etc incurred
through non-compliance, however, will
_not_ be considered part of the cost of
the project.
Imaginative scavenging and borrowing is
encouraged, but only within the spirit of
the challenge. Broadly, extensive use of
salvaged or redundant space hardware is
unlikely to be permitted. In the same
spirit, a wealthy sponsor who custom-
builds something and then "lends" it to
the project or sells it at an unrealistically
low price, would breach the rules.
[***>>>>>>> The above is the idea as originally posted.
Please visit the N-Prize site for the current rules for the real-world
N-Prize. In particular, only 9 (not 99) orbits are now needed, and
there is now a second prize category for reusable vehicles with a
*per launch* cost below £999.99, as well as the original single-
spend-to-orbit prize<<<<<<<***]
Starshine
http://www.azinet.com/starshine/
No batteries. It blinks. [Amos Kito, Feb 13 2008, last modified Feb 14 2008]
Planet You
Planet_20You
use the winning system to send these up one at a time [xenzag, Feb 14 2008]
HARP
http://en.wikipedia...g/wiki/Project_HARP
Cheaper than rockets ... [8th of 7, Feb 14 2008]
Another HARP link
http://www.astronau...ticles/abroject.htm
//I saw a show that said we (USA) built a small one// 176 feet a small one? You must be a Texan [coprocephalous, Feb 14 2008]
National Association of Rocketry
http://www.nar.org/
WP states licenses usually mimic these for other countries [MisterQED, Feb 15 2008]
Tripoli Rocketry Association
http://www.tripoli.org/
[MisterQED, Feb 15 2008]
Cool Balloon link covering some regs
http://vpizza.org/~jmeehan/balloon/
Detail of a guy launching a weather balloon [MisterQED, Feb 15 2008]
Weather balloon suppier
http://www.kaymont.com/pages/home.cfm
[MisterQED, Feb 15 2008]
(???) B.C. inventor wants to put pop bottle rocket into orbit
http://www.cbc.ca/c...0217/K021704AU.html
[tatterdemalion, Feb 18 2008]
Low Earth Orbit details
http://en.wikipedia...iki/Low_Earth_Orbit
[MisterQED, Feb 20 2008]
Energy Density - Lately my favorite page of Wikipedia
http://en.wikipedia...wiki/Energy_density
[MisterQED, Feb 20 2008]
Westphalia, Germany
http://en.wikipedia...th_Rhine-Westphalia
I have no idea what this has to do with anything, though. [jutta, Feb 20 2008]
Rockeloonannon
Rockeloonannon
[BunsenHoneydew, Feb 28 2008]
Are Amateur Orbital Rockets Possible?
http://gramlich.net..._rockets/index.html
[MisterQED, Mar 18 2008]
The N-prize Web site
http://www.n-prize.com
Please visit the site for the latest rules. [MaxwellBuchanan, Apr 10 2008]
Attacking Space like Everest
http://groups.googl...t-a-staged-approach
Way too long to post here but hope it deserves the link [MisterQED, Apr 15 2008]
N-Prize in the New Scientist space blog: Whimsical 'N-prize' to spur ultra-cheap space launches
http://www.newscien...%20space%20launches
Well done, MaxwellBuchanan! [django, Apr 28 2008]
Amateur spaceshot success
http://en.wikipedia....22GoFast.22_Rocket
Never knew about this one [BunsenHoneydew, Apr 29 2008]
Radio report on N-Prize
http://www.abc.net....8/04/08/2210606.htm
Go to the topmost of the audio links on the left, starting about 5 minutes in. Regrettably no mention of the HB.... [MaxwellBuchanan, Apr 29 2008]
A Cult of Backyard Rocketeers Keeps the Solid Fuel Burning
http://www.nytimes....00&partner=homepage
[Klaatu, Apr 30 2008]
More blatant elf-promotion
http://archived.the...-BWB-2008-06-06.mp3
The Space Show 6th June, about N-Prize. [MaxwellBuchanan, Jun 07 2008]
Slashdot article
http://science.slas...06/17/1420213.shtml
nice work. front page of slashdot [xaviergisz, Jun 18 2008]
Another Mad Scheme
http://jca3.freeshe...pace/spacebets.html
Similar to N-Prize but self-funding. (An old fantasy of mine.) [jcatkeson, Jun 20 2008]
Slashdot again
http://science.slas...07/27/1952255.shtml
Cambridge N-Prize Team To Build Balloon-Assisted Rockets [xaviergisz, Jul 28 2008]
"Teens capture images of space with £56 camera and balloon" (Telegraph)
http://www.telegrap...ra-and-balloon.html
"Teenagers armed with only a £56 camera and latex balloon have managed to take stunning pictures of space from 20-miles above Earth..." [hippo, Mar 18 2009]
Idea prompting the suggestion of a "spud-gun" boost
Pre-Stage_20fueling_20tower
[MaxwellBuchanan, May 02 2009]
HARP
http://en.wikipedia...g/wiki/Project_HARP
[MisterQED, May 13 2009]
Latest from an N-Prize team
http://n-prize.goog...bGy6NOIihTzJrOKHvyT
From a high-altitude balloon, by Team Prometheus. Next stop - Uranus. [MaxwellBuchanan, Jun 12 2009]
Cheese tied to a balloon
http://news.uk.msn....ocumentid=148891047
What better way to celebrate the lunar landing than by launching some cheese? [marklar, Aug 02 2009]
Interorbital Systems – TubeSat Personal Satellite Kit
http://spacefellows...onal-satellite-kit/
launch your own satellite into orbit for $8,000 [xaviergisz, Aug 02 2009]
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Annotation:
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<Zoolander moment>What is this? A space program for ANTS?!?</Zm> |
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Or uncles. Or anyone, in fact. |
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One problem with this is going to be to
get the necessary cooperation in
detecting the signal. The femtosatellite
is going to be in a (probably) uncertain
and unstable orbit, and will be emitting
a very weak signal at long intervals.
Detection would require a lot of
international co-operation, I imagine.
This in turn would require the challenge
to be well-publicised, such that
detecting the signal would become as
much of a sport as putting the thing up
there. Unless anyone has any smarter
ideas. |
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Nice, I was just coming home to post this, so I guess I like it (+), though the prize needs to be larger. The permits are going to cost a thousand or so. |
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Man those are strict weight limits considering the signal has to be "heard" from Earth. I think to only thing that efficient is a directed LED light and the receiver is a telescope. Still even for that I think you'd need a gyro so the LED is aimed roughly Earthward. |
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Could you use a reflective tail fin for direction? That would only fix one axis. |
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For 10 grams you can get a small solar panel, capacitor, timer, and a xenon flash tube. |
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// The permits are going to cost a
thousand or so.// The awarders of the
prize strongly discourage the seeking of
permits, and the cost of such permits
will be considered part of the cost of
the launch. |
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//Man those are strict weight limits //
We might consider revising this to read
"payload of at least 10 grams", though
the cost limitation would probably
favour lighter, more ingenious craft. |
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I like the idea of optical detection -
would it work? How easy would it be to
scan the skies for a flash tube at orbital
heights? |
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Starshine [Link] was in orbit at 390km, and covered in small mirrors (maybe 3cm dia.). I don't think it was much trouble for people to locate, when they had the track info. With an integral strobe, you wouldn't rely on a solar reflection -- so you could watch for it all night. |
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<slightlly off-topic> STARSHINE has to be the best case of an acronym that fits (too) perfectly with what it is. Do you think they came up with the abbreviation first, then tried to fit description to it? (For those who don't know, STARSHINE is Student Tracked Atmospheric Research Satellite Heuristic International Networking Experiment.)</sot> |
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You could just use 10 grams of radioactive material, that should be fairly easy to detect. |
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I believe the current cost of launching stuff into ordit is around $10,000/kg. I think a better competition would be that you have to get an amount of cargo into orbit for less than $10 per gram. So that would mean around 200 grams for £999.99. |
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That should be within the realms of possibility, after all, it's not brain surgery. |
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//it's not brain surgery//
This is why I had such a hard time breaking my addiction to this site years ago. That's rightous! |
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//You could just use 10 grams of radioactive material, that should be fairly easy to detect.// Would it? Isn't one of the nasty things about space is all the fun radiation blowing around, wouldn't it get lost in the rest of the radioactive background noise? |
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Each type of radiation has a frequency, including light. If you choose an element which emits a frequency which is distinct from the background radiation, and suitable for penetrating the atmosphere, you would have a better chance of detecting it than a light-emitting device of the same size. |
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I guess you could use a piezo crystal and a watch battery to emit radio waves at a specific frequency instead. |
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Fortunately for us, our atmosphere is totally opaque to alpha particle (helium nuclei) and beta particle (electron) radiation, and severely attenuates radiation all the way across the gamma band. For example, the Van Allen radiation belts are not detectable from the earth's surface. (The radiation part, anyway. Indirect measurements can be done with VLF radio.) Satellites have been developed that can spot radiation from a nuclear explosion, but they can't find geologic deposits of radioactive ores. (At least, not by means of emitted radiation.) |
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Just get rid of the weight limit, the cost limit pretty much sets a maximum weight and the stipulation for trackbility sets a minimum. |
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Oh yeah, and up the budget a little. Around here, $1000 / £500 would be a good budget if you wanted a vehicle that just might make it south of the river. It's not really going to get anything into space, no matter how ingenious you are. Maybe $10,000? |
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//I don't think it was much trouble for
people to locate, when they had the
track info.// Yes, but we may not have
any track information - remember,
we're not going for a precisely defined
orbit. |
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//radioactive material, that should be
fairly easy to detect. // Not from the
ground it won't be, alas. |
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//a better competition would be that
you have to get an amount of cargo into
orbit for less than $10 per gram//
Well, what I'm hoping for is for people
to be doing this from their back
gardens. As soon as you start trying to
launch heavier things, it becomes more
hazardous and perhaps less innovative. |
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// £500 would be a good budget if you
wanted a vehicle that just might make it
south of the river// |
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The budget is actually £999.99, and
stays. It is almost impossible to do it
for that, but 'almost impossible' is the
aim. Like the man said "Gentleman, we
haven't any money, so we will have to
think." |
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£999.99 buys a lot of aluminium,
electronic components and string.
What you do with it is up to you. |
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"I want a rail gun, to these specifications, and a 20 gram pellet made of pure chromium metal enclosing a microtransmitter broadcasting on AM 500Hz. Can I borrow your rail electrification transformer farm for a second?" |
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[UnaBubba] The would be a valid
solution. Imaginative borrowing of
hardware can form part of the deal,
provided that the loan is reasonable and
in the spirit of the competition. The
loan of equipment should not involve
unusual expense on the part of the
lender (eg, a corporate sponsor is not
allowed to construct a railgun for your
launch, and then "lend" it to you in
exchange for publicity), and each case
will be judged on its merits. |
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I suspect, though, that a 19.99 gram
projectile will be either melted or
stopped by air resistance shortly after it
leaves the railgun. |
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That would depend on its aerodynamics. |
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For that money, it might be possible to build a 10mm calibre "Hochdruckpumpe" - type multistage gun barrel. That might just be able to fling a small projectile into LEO. |
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But stand well clear when you fire it ..... |
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//I suspect, though, that a 19.99 gram projectile will be either melted or stopped by air resistance shortly after it leaves the railgun//
A multi-stage sabot round?
A sort of high velocity matrioshka |
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//A multi-stage sabot round?// by all
means, as long as you can build it within
weight and cost. |
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I thought about railguns but I assumed the magnetic field would fry any electronics in the projectile. Would it? Can it be sheilded? Or did they ever perfect a diamond semiconductor? |
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The supergun idea is also a good one especially since I saw a show that said we (USA) built a small one which went pretty high but they lost funding to build the "real" one. I'd love to buy the old one for the price of scrap. Then create a sabot round for my own micro satelites. |
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//might be possible to build a 10mm
calibre
"Hochdruckpumpe"// This I like,
especially if it can come with umlauts.
Don't forget you've got to get
sidewaysness as well as uptitude in order
to acheive orbit.. |
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Re. the HARP project and other "guns", I
don't think it's going to work. First, the
£999.99 has to cover *all* the
hardware, including whatever stays on
the ground. Second, all of these launch
systems use very heavy projectiles to
ensure that air resistance is not
disasterous. |
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Although the rules don't stop you from
using a sabot around a lightweight
femtosatellite, you're still going to need
to launch several hundred pounds of
stuff. Even if the sabot itself costs less
than £999.99 to make, you're looking at
a huge launch facility. |
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The only solution I can see as working is to launch one of those high altitude weather balloons to 170k ft and then launch a solid fueled rocket to get the last 70 miles up and get all the sidewaysness that you will need. |
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I'm all for yogic flying. I really like the idea of 8 minutes of 4.5g yogic acceleration in a vacuum environment. <cue sideways-travelling lotus-position maharishi whoosh> |
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//The only solution I can see as working
is...// Yes, that sounds like a plausible
solution. |
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//Fire your object at an existing
satellite, and make it stick to it.// Not
allowed, alas. Your device has to be
self-contained and self-sufficient, and
can't piggyback on anything during the
launch or orbit. In any case, I would
have thought that hitting a satellite on a
£999.99 budget was optimistic. |
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//Do the subsequent legal costs count
in the £999.99 limit?// No. Costs for
complying with regulations are counted,
but not legal costs or fines for non-
compliance. |
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Balloon and mini rocket would be the go. Surprised no-one has ever done it. |
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//Balloon and mini rocket would be the
go.// I agree. I was thinking of the
following. The satellite will be three
disc-shaped solar cells, intersecting to
form a sort of sphere. The electronics
will be on a postage-stamp-sized
board, glued to one of the panels near
the middle, and will consist of an
accumulator to store charge, and a
transmitter which fires for a second or
so once enough charge is built up.
Because the transmitter does not run
continuously, I'm guessing that the
components can be run above their
normal operating limits to maximise
power. |
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The launch platform is a helium (or, if
cheaper, hydrogen) balloon. Suspended
below it is a 2m string, forking into an
inverted Y at the bottom. The legs of
the Y are unequal, and from them
hangs the launch shaft. Thus, the angle
of the shaft to the horizontal will be
pretty accurately maintained. (We don't
care whether the thing fires north,
south, east or west - hence, no need for
guidance or targetting). |
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The rocket itself has a hole up the
middle, and is basically impaled on the
launching shaft (lighter than a tube).The
rocket will have no gyros, but is
stabilized by spin: the propellant and
vents are arranged such that the first
half-second of burn fires from two
sideways-directed vents, starting the
rocket spinning before it leaves the
shaft. The rest of the burn then
provides forward thrust only. |
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The rocket flies until it runs out of
propellant - no precise control. The
satellite itself is slotted into the nose of
the rocket, and retained by a spring clip
somewhat similar to the mechanism of
a retractable ball-point pen. When the
rocket accelerates, it compresses a
spring (click!) and then, when it runs
out of propellant and stops
accelerating, a lighter spring simply
pings the satellite clear of the empty
rocket. |
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How's that for simple? Doable for
£999.99?? |
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//Surprised no-one has ever done it.// Un-surprise yourself. Google "rockoon". It's what James Van Allen was up to when he first found traces of those radiation belts. |
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The "rockoon" links look very
promising.
Altitudes of up to 80km with heavy
payloads, which is only a shade below
low
earth orbit. They say a major drawback
is
lack of control over the balloon but,
since
we don't care, this isn't a problem at all.
All looks pretty feasible to me. |
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I will gladly make the prize money
available for a real N-prize, if anyone
has any ideas on how to make it real.
It'd have to find a home outside the HB,
though - I'm sure Jutta wouldn't want to
be impllicated if someone gets a lump
of rocket on their head. |
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Please let me design the site if you do! I love doing spacey graphics. |
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[MB] very good, except we dearly care about the direction the rocket launches. As the launch vehicle is already travelling roughly with the spinning Earth at 1000 mph, we want to add to that speed and head due east. |
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Also I'm wondering about the solar cells. I have to look this up, but they said 100 orbits. At the low end of LEO, 100 orbits isn't that long. A lot of satelites orbit every 90 minutes. We will be lower and faster. 100 orbits may only be a day or so. Also are the solar cells we buy able to operate in space? Heat extremes, etc.? |
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And BTW, what does the N stand for? |
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[wags] you're on for the website if this
takes off. |
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[QED] //we want to add to that speed
and head due east.// Ah, yes, good
point. Hold the moon-landing. OK, so
we have two choices. Either we put a
directing mechanism on the launch
balloon; or we put a simple compass in
it, and set it to trigger the rocket when
it happens to be pointing east (at the
top of its travel, of course). I think the
latter will be lighter/cheaper/more
reliable. |
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//Also I'm wondering about the solar
cells.// If batteries would do the same
job for a day (and for less weight) then
all well and good. I think regular solar
cells would survive, but we could check.
The only real issues would be vacuum
and temperature fluctuation; I don't
think the launch would be too violent,
and I doubt that solar UV or other
radiation would be a problem for a day
or two. |
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//what does the N stand for?// It
stands for "next to no money", and also
for the nines (9.99-19.99g, 99 orbits,
£999.99...) |
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Does anyone know anything about the
legalities of shooting things upward?
Model rockets are no problem, and nor
are toy helium balloons - are these
things controlled according to weight or
altitude? And what's the worst penalty
you can face (in the UK, US, or
wherever)? The overall aim is to
discourage over-compliance and damn
the consequences, and allow for a little
natural selection amongst really dumb
rocketeers, without seriously
jeopardizing innocent bystanders. |
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I'm assuming that detection
of the orbiting satellite would require
the cooperation of radio-astronomers
or the like, but I'm guessing they might
be willing to play along. |
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I think it should be reasonably easy to gyro stabilize the launcher so that it always points the rocket east without adding too much weight. As for the limits on rockets, there are many. I'd suggest looking at an issue of "High Powered Rocketry" magazine or borrow one from [8/7] who probably has a subscription. I haven't looked in a couple of years, and I'm sure it is nationally dependant, but such things as fuel load , fuel types and metal housings are strictly limited on a graduated license scale. Weirdly enough I wonder if the rules still apply since you will be launching the rocket outside of national airspace (doesn't it stop at some altitude). |
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//also for the nines (9.99-19.99g, 99 orbits, £999.99...)// |
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I swear it said $1000 when it was posted... |
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[wags] Rockoon == inflation |
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//I swear it said $1000 when it was
posted...// It did. Actually I think it was
"£1000". I've also made a few
minor edits to the rules. |
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What we need is publicity - some way for
people to find out about the N-prize,
perhaps by having Google find the X-prize
and the N-prize mentioned together on
the same web page. If only there were
some way. |
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//I think it should be reasonably easy to
gyro stabilize the launcher// but why
not just let it wander, and fire when it
happens to be pointing the right way? |
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//graduated license scale.// Well, as
long as we don't kill anyone important.
Anyway, only those who fail are liable to
be prosecuted - who's going to have
the nerve to charge the world's first
backyard satellite launch facility owner? |
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//why not just let it wander, and fire when it happens to be pointing the right way? //
I haven't done model rockets for years, really decades, but I do remember a bit of a delay between trigger and launch, so if for some reason this thing starts spinning on the string, you could be way off. |
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Yes, true. However, the sensor that
fires the rocket will be on-board to
reduce delays. Also, the balloon itself
will be very wide, which must limit the
rate it's likely to spin at; as long as the
rocket-tube-tether is linked
unswivellingly, spin should be limited.
Failing that, have the direction sensor
detect rate of spin also, and not launch
when spin is high. |
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Of course, weight penalties on the
balloon are not as harsh as on the
rocket or satellite, but I'd still like to
keep things as simple as possible. |
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I'm just checking some prices and stuff.
Helium for a 10ft diameter balloon is
going to cost about $30. |
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Does anyone know what is used for the
skin of high-altitude helium balloons?
In photos it looks like polythene, but
would this not become very brittle at
high (cold) altitudes? |
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Can anyone think of any part of this
system which is going to cost more
than $100 in materials? |
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[EDIT - thanks for the balloon link, QED.
Looks as if US regulations are not a
problem at all! Note that the latex
weather balloon is not designed for very
high altitudes - it doesn't allow enough
expansion to avoid bursting.] |
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Mylar is the best material for helium balloons. It's less porous than most plastics / rubber and stronger. |
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To ensure you launch due east you merely have to make the launch platform of something highly magnetised. I would also make it reasonably heavy, to minimise the problems of "equal & opposite reaction" causing guidance issues, upon firing. |
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I believe there's a fair bit of hydrazine doing fast laps of Earth right now, if you want to save on fuel costs. |
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//Can anyone think of any part of this system which is going to cost more than $100 in materials?//
The rocket propellant and the helium to get the rather large rocket up to 150k feet. |
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I don't entirely get the hydrazine
reference? |
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Re the mylar balloon, isn't mylar a
favourite because of its low helium
porosity? Since that won't be a factor
on a short flight, would some other
material be lighter/better? |
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Regarding the satellite itself, a balloon-
type mylar reflector might do for that
too. 20 grams lets you make a roughly
foot-wide balloon of 0.1mm Mylar,
which could be inflated in orbit. The
"Echo1" satellite was a 100ft mylar
balloon, and was bright to the naked
eye from earth. We'd have only
1/10,000th the area, but I suspect it
would still be easy to spot with a small
ground-based telescope. |
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[wags] - "N-prize.com" is not yet
taken.... |
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Hello halfbakers ! [my first post, so I'm nervous - hope I'm filling the right box in here !] |
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WRT facing East, and getting maximum lateral speed, how about trying to get the balloon up into a jetstream before launching the rocket. Or do these occur too low in the atmosphere ? How high will a ballon go ? |
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Obviously some fins on the launcher would keep it in line in the airflow |
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// I don't entirely get the hydrazine reference? //
There's going to be quite a lot of it soon when the US blows up one of its own satellites. |
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//how about trying to get the balloon up
into a jetstream// Unfortunately, the jet
streams are way too low (about 10km).
But welcome to the HB, VaquitaTim. |
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[QED] thanks for the weather balloon
supplier link. Theirs only go up to 40km,
alas - mainly because they're sealed. I
believe high-altitude balloons are
launched "flaccid" and expand greatly as
they climb. |
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//The rocket propellant and the helium to
get the rather large rocket up to 150k
feet.// Well, it's not going to be a rather
large rocket, I was thinking more along the
lines of rather small. Helium is about $37
per 1000 cubic feet. Rocket propellant is
as cheap as your imagination. |
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Why pay for helium when hydrogen is cheaper and has better lift? |
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True. So, we save $30 by electrolysing
water - sounds like a good deal to me.
Maybe we should reduce the budget to
$99.99..... |
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[wags] I just bought n-prize.org,
and .com, and .co.uk and .info.
Unfortunately I have no idea how to
establish a website. |
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Get someone to set up a domain hosting and we'll load Joomla! onto the page and get started. Joomla! is open source so it's free software. |
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[wags], do you have a hosting solution handy? I've done a fair bit of content management work with Joomla! but I buy the setup and template readymade. |
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Domain hosting..... Joomla!...... right....
hang
on. Will investigate... |
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//I just bought n-prize.org, and .com, and .co.uk and .info.// Once again the Buchanan's take occupation of lands they have no specific intentions of using, apart from croquet and fox hunting that is. |
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I hadn't noticed any foxes on N-prize.org,
but I'll check. I also claim the mineral
rights. |
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[UB] and [wags], if you're serious about
helping with the website, I'm interested. I
have no idea what I'm getting into here,
which is the perfect starting place. |
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Not sure if this could be done within the weight limit, but a possible solution to the verification-of-orbits question could be to have the satellite take a sequence of Earth photos to establish "At 2:30 I was here, at 2:31 I was HERE, at 2:32 I was HERE...." Once 99+ orbits are complete, transmit these photos. In order to prove these are real photos and not not pre-recorded or Photoshoped, they would have to be compared to actual weather patterns, the known positions of aircraft in flight or ships at sea, known traffic jams, large gatherings of people (and their cars) at outdoor venues such as ampitheaters, sports stadiums, or campaign/protest rallies etc. Obviously a very high-res camera would be required to obtain verifiable details. |
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[gardner] I suspect that the weight
penalty would indeed be a problem.
And, if you can transmit photos, you
could transmit a locating signal. |
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[UB] and [wagster] the outfit I bought
the domains from also offers hosting
(telivo.com) but I don't know which
package I need. I'm happy to buy
whichever one I need. Presumably,
after that, anyone with access to the
site can upload pages? |
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Yup, that's about right. I can provide hosting, but it would probably be easier for you to host it where you bought it from. You shouldn't need much webspace for this - 100Mb should be more than sufficient. |
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Shall we take this to email if it's going to get in-depth? Mine is on my profile page. Drop me a line. |
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To email it has been taken. I have the
feeling that we're creating a monster here,
but the important thing is probably not to
be too sober when any important decisions
are taken. |
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Do you think there will be trouble down the line with the name being similar to Nobel Prize? I Googled N-Prize and got a lot of references to the Nobel. |
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I can't imagine there being a problem; the
Nobel may be referred to sometimes as
the "N-prize" colloquially, but I don't think
there's any risk of confusion. In any case,
I've got the domain name, so hah! |
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//Imaginative scavenging and borrowing is encouraged// |
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So I can just super-glue my coins to the next US space mission? |
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// Broadly, extensive use of salvaged or redundant space hardware is unlikely to be permitted// |
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Full rules will be available shortly on n-
prize.com |
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I think the hardest part will be to accelerate this thing up to n-gazillion metres per second, so that it actually stays up there.
What are we talking about - 8000m/s? |
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Nearer 7500m/s for the lowest low-earth
orbit. A handgun can sent a bullet at
something like 1500m/s, so you're looking
at five times that, in terms of speed, or 25
times that in terms of kinetic energy for a
satellite of comparable mass. |
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Surely accelerating something very light in a total vacuum can't be that hard? I think ion drives are good at this kind of shennanigans. |
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It shouldn't be that hard. However, an ion
drive is way too slow (your satellite is
going to re-enter long before the ion drive
has done much good). |
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Has anyone done the math to find out a rough guess as to how many model rocket engines will get us from 170000 ft to orbit assuming no air drag? |
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Depends on the final payload and on the
rate at which mass is shed during the
ascent. Ideally you want a staged rocket.
Even then it'll be close or impossible with
those motors, since their energy density is
quite low. |
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//Has anyone done the math // |
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To start out on the math, google "rocket equation". You're going to need a delta-v of nearly 10km/sec in order to get into low earth orbit, because a fair amount of your velocity gets killed off in getting your potential energy (altitude) up. |
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//how many model rocket engines// - answer: model rocket engines in any configuration will fail. They don't have a high enough specific thrust, and they don't have a high enough fuel fraction (the cases are too heavy). |
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You're going to have to use something other than a black powder fuel. There are high-energy solids that can do it, but they are very very picky about production and are not cheap and hard to control. There are liquid fuel engines in several configurations which are capable, but require pumping & metering & throttling & mixing & cryogenics & tankage & plumbing & are very un-cheap. A possibility might be a hybrid - a solid fuel grain with a liquid oxydizer (as in Rutan's design - but note that he got to less than orbital altitude with *zero* velocity at the top - he needed about another 7500m/sec of delta-v to make that into an orbit) but having one with a sufficiently stable burn profile to not blow up / go asymmetrical / blow out chunks of unburned fuel grain is still quite in the realm of experimental. |
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Plus, please remember that solving all the problems of putting a payload in orbit entails solving every one of the problems posed in the building of an ICBM. Regardless of your intentions, think for a moment on whose attentions that is going to bring to you. |
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//Regardless of your intentions, think
for a moment on whose attentions that
is going to bring to you.// On the one
hand, true. On the other hand,
bollocks. The aim is to do the nearly
impossible against overwhelming odds
with almost no budget and for virtually
no reward. Did the Wright brothers
worry about governmental dissapproval
when they invented the Model-T light
bulb? Did Edison fret about military
uses of the spinning jenny? No!
Launch and be damned. |
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Also, I might point out that if a
schmuck in a shed can put something
into orbit for under a grand, it's in
everybody's interests to have it out in
the open. |
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//Regardless of your intentions, think for a moment on whose attentions that is going to bring to you.
//
Richard Branson? |
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I didn't say "stop immediately, because al-Qaeda will abduct you and extract your secrets nasally" - I just said 'consider'. If you think the Wright brothers' feat could be accomplished today without Homeland Security having palpitations, you are an optimist. |
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If you have a chance to come to Utah (the Bonneville Salt Flats) in early September, you'll want to attend "Hellfire" - an international amateur rocket launch. You'd get to see rockets where just the solid fuel grain alone runs over a thousand bucks. (I take my little $10 model out, fly once, and sit back and watch the other guys burn a month's pay in 4 sec. I once got to stand next to a guy whose 14 ft. $3000 rocket failed to deploy 'chutes - absolutely beautiful machine, stunning paint job, turns over at 7k feet and comes straight into the salt at over 500 knots. He cried for about a half hour, then committed to "do it again next year".) |
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I'm agreeing with [lurch]. This contest could be re-named as an anti-satellite-weapon challenge without being re-written. I like it, and I've a couple of new ideas, but no matter how I put the parts together, they keep coming out a weapon. |
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// I just said 'consider'. // Well, I
disagree
with that too. Too many people
consider
too much. Sometimes it's just right to
pretend we're back in democratic days
and
plain do things. Sometimes it's nice not
to
think about who's watching over your
shoulder. The very idea of an
organisation that calls itself "Homeland
Security" (why not "National Security"?)
gives me the heebie jeebies, and I don't
even live there. |
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But thanks for the invite to Hellfire -
sounds fun! |
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//On the one hand, true. On the other hand, bollocks.// |
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//This contest could be re-named as an
anti-satellite-weapon challenge without
being re-written.// Well, only if you
find a way to add guidance, not just to
the launch system but also to a satellite
weighing less than an empty coke can. |
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By this reasoning, nobody except the US
Government is allowed to develop
anything that can go upwards. To
quote (for the second time) my great
great aunt Agathenia, bollocks. |
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Good point, as always, [MB]. My bullocks, there. |
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You can't get into orbit without guidance. |
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If you want to be at the minimum altitude for orbit, say for example you give yourself +/- 10 km leeway, and you want to do 100 orbits, then you have to be going in a direction which will allow you to still hit that 10 km slot at the *end* of 100 orbits. So, it's going to need to be, at a minimum, accurate enough to hit a 10 km slot at (40,000 km * 100 orbits) = 4 million kilometers distance. |
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Even saying you could do one orbit without guidance would be like saying that trans-oceanic airliners don't need navigation systems, just point in the general direction and go. |
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//You can't get into orbit without
guidance.// You certainly can. You
need
to make sure you've got enough velocity
and you need to be pointing in roughly
the
right direction. Beyond that, it really
doesn't matter. You need very good
guidance to get into a *particular* orbit,
but that's an entirely different kettle of
wild herring. |
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Or perhaps you meant that you can't get
into orbit without suitable mentoring? |
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The number of possibilities of your orbit depends on how much space there is between your altitude and the atmosphere. If you're at minimum altitude, you have a very narrow range of directions you can fly. Higher buys you more leeway, but it takes even more thrust to get there. |
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One item that causes a problem, but is non-obvious, is that you can't make your orbit *not* pass through the point where you were when you last altered your orbit. If you are in a circular orbit, and fire your thrusters when you cross Ecuador, for example, then on your next orbit you will pass over Ecuador at the exact same altitude as before. Your velocity will be different, but not altitude. Your altitude will be different over Sumatra, and if you fire again over Sumatra, you can change your altitude over Ecuador. |
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To sum up, a circular orbit requires, at minimum, an original boost and a circularization a half orbit later. Otherwise, your payload will attempt to fly through its launch point. (And when I say 'circular' here, I don't mean 'within five balls two of a perfect circle', I mean 'close enough to get back to point A without an unplanned re-entry'.) |
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Yes, true. If you want to keep at
minimum altitude, you don't want your
orbit too eliptical, hence the 'roughly
the right direction'. But that's not the
kind of guidance you need in order to
hit something. |
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The kind of energies you need to get a
small mass into orbit from an upper-
atmosphere starting point are not
orders of magnitude greater than those
you get from a handgun. The kind of
guidance and communication
equipment you need is not significantly
more complex than the electronics in a
mobile phone. |
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Commercial, scientific and military
satellites need to actually do stuff and
stay in the right place, and this
increases their cost and weight by
orders of magnitude. All we want to do
is to send a matchbox about a hundred
miles up and make it go round a few
times. Everything works in your favour
when you sacrifice weight and
functionality, by exponential rather than
linear factors. |
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That doesn't necessarily hold all the way down to zero size. |
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Here, let me tell you what your first show-stopper will be. You've launched rockets, seen them launched, it all looks pretty simple. The standard model rocket, the 3FNC (literally "3 fins and a nose cone") makes it appear so natural that you light a rocket, and it goes up. However, there's magic going on there. It's the fins. You use a launch rod to keep the rocket pointed up until it is moving fast enough that any deviation from moving in a straight line puts air flow against the fins, creating a force couple which corrects the line of flight back where the nose cone is pointing the way. |
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However, you would like to simply start out with no air resistance by firing from above the sensible atmosphere. Or, at the very least, passing above it. What, then, keeps your rocket pointed even in the "general direction" you would like it to go? Nothing. In real rockets, this is accomplished by a horizon scanner or a gyroscope, controlling a gimballed rocket nozzle and/or a set of vernier rockets. Without that guidance system, your problem is no different from balancing a nail on its point. It may work for a moment, but your rocket's thrust is not going to be utterly turbulence-free, and thus is doomed to tumble. |
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My version of the N-prize would be to fly a rocket with no fins or drag stick (read this as "stable in vacuum") to 1000 meters for the same price as you're saying for orbit. |
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What is the viability of hosting a kind of single shot LONG (2-3M) barrelled rifle? Use a .50 caliber cartridge and sabot the bullet. The pressure would be lower due to the lighter round, so the barrel wouldn't have to be as heavy. |
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[lurch] that which you say is true. My
intention (see earlier anno) was to spin
the entire rocket about its axis, gyro-
wise. However, if it needs a gyro for
stability, then it can have a gyro for
stability. It's up to the entrant to figure
out how to machine a gyro within
budget, or how to imaginatively
'repurpose' a VCR head or a 12V-driven
microfuge for that function. |
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Incidentally, rockoons relied mainly on
fins for directional stability, though
granted they were only scraping the
edge of space. |
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[QED] you mean a ballistic launch from
under a high-altitude balloon? Yes, that
may be feasible. One concern might be
recoil of the gun (and consequent mis-
targetting), but I expect you could get
around that problem. You've also got to
have a satellite hardened against the
acceleration, whilst also being detectable
in some way from earth. But possible, I'd
have thought. |
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For a simple rocket could you acheive stability
on-the-cheap by starting with an electronic tilt sensor from a digital camera? These seem incredibly sensitive and could control the direction of the rocket by, for example, discharging a small capacitor into one of a number of tiny explosive charges (e.g.a 'cap') on the side of the rocket.
The other thing that occurs to me is that you can do a lot in under 10 grams - my son's remote-controlled helicopter has an IR receiver, some control electronics, a battery, the helicopter body, two rotors, two electric motors and it still weighs less than 10 grams. |
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Excellent thinking, Hippo. The point about
the ten-gram helicopter is very well taken,
and of course that ten grams includes a
propulsion system which, provided we can
kick it off in the right direction, the
satellite shouldn't need. Can we register
you as an entrant? |
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ooh yes, I'd be keen (despite knowing nothing about rocketry, propulsion systems, navigation,
three-dimensional geometry, radio, radar, aeronautics, etc. - I'm good at countdowns though). |
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You bought "your son" a PicooZ helicopter for Christmas too, [hippo]? |
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Christmas 2006, yes - and it was the PicooZ model - absolutely amazing. |
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//despite knowing nothing about....// A
healthy dose of ignorance is a tremendous
advantage in these circumstances. |
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//A healthy dose of ignorance is a tremendous advantage in these circumstances//
I don't want to discourage anyone, but this is rocket science, so we all probably start with a healthy dose of ignorance. |
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To that point, I just found out that purely cannon launch is out. We need ~7km/s speed for LEO and even HARP only got to 1/4 of that, so we are back to rocket science. |
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Oh and my favorite number so far is orbital energy = 32.1MJ/kg. You may want to look at the energy density link to see what kind of power you will need for the trip. |
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Yes, but it all depends on the mass of
the projectile and other stuff. Some
gas-guns used for testing impact at
orbital velocities have achieved >7km/
s. |
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Put it another way. We need to get
about half a megajoule of energy into a
20gram satellite (to get it up there and
orbiting). This is the energy used by a
small electric heater in about nine
minutes. That's the energy obtained by
burning *four grams* of liquid
hydrogen with about 32 grams of liquid
oxygen, or about a tablespoon or two in
total. Of course, that's a naive
calculation because the energy of
combustion doesn't all (or even mostly)
go into the satellite. But, the point is
that we're not talking about silly
amounts of energy here. |
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As I mentioned earlier, once you're clear
of the atmosphere, smaller devices
become very much easier to put into
orbit. |
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[EDIT] a little more interesting
information. A multi-ton ground-
launched solid-fuel rocket manages
about 2% payload (ie, it can deliver
about 2% of the launch mass into low
earth orbit). For small, ground-
launched rockets it gets much worse,
because most of the losses are in air
resistance. But for a high-altitude
balloon-launched rocket, this isn't a
major factor. |
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And it gets better. Most of the non-
propellant mass of a solid rocket is
needed to contain the combustion
pressure. It turns out that a smaller
tube can be relatively less massive, and
hence smaller rockets have a lower
shell-mass. So, we can certainly expect
a small ballon-launched solid-fuel
rocket to give at least 2% payload-into-
orbit, and probably nearer 3 or 4%. |
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On this basis, even a solid-fuelled
rocket only needs to be about 1kg total
mass in order to deliver a 20g payload.
Quadruple that to allow for irreducible
masses and sod's law, and you still have
a rocket weighing less than ten pounds.
This has to be lifted by a helium
balloon, which will need to have a
volume of about five cubic metres.
Double everything again to allow for
hardware that remains attached to the
balloon, and you're still only up to a ten
cubic metre helium balloon carrying a
ten-pound rocket tipped with a 20g
satellite. |
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Incidentally, the mission could be
launched from anywhere that's not too
polar, except for mid-west Germany.
Westphalia is _not_ an option. |
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Which Westphalia?
Google Maps gave me 7 in the USA. (Dunno about the rest of the world.) |
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[n_w] The clue is in "mid-west Germany".
[jutta]It is a kind of pun, see Apollo 13 (spoken by Ed Harris, IIRC).
Actually, I think it would be perfect for a ham rocket operation. |
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[jutta], [AbsintheWithoutLeave]; thanks. I figured it must have been in Germany - Google Maps is usually better than that (not so USA-centric).
Regarding ham rockets, ever see the Mythbusters episode with the Civil War (I think) meat rocket? |
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// It turns out that a smaller tube can be relatively less massive, and hence smaller rockets have a lower shell-mass.// You got that relationship backwards. |
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//On this basis, even a solid-fuelled rocket only needs to be about 1kg total mass in order to deliver a 20g payload. Quadruple that to allow for irreducible masses and sod's law, and you still have a rocket weighing less than ten pounds.// |
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If you take your ten pound rocket, put it on a balloon, fly it to the world record altitude height for a balloon plus ten percent, it will still be incapable of reaching orbital *altitude*. Forget turning the corner and trying to then tack on orbital *velocity*. |
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You might want to ask yourself, "If my assumptions say that this is so incredibly easy, why are all the other people who've tried such idiots?" Then try searching to find out. |
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I'm sorry, I actually like the idea, and think that there is a good area here for positive achievement. I am very concerned, however, that people can go into this with bad assumptions, waste time and money, and maybe get hurt. I like amateur progress, and hate to see things set up where amateurs fail spectacularly and give the next group a bad rep by association. So if I've come across sounding like I'm attacking you, please understand that is not my intention. Just frustrated. |
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Back to the issue at hand - I would that you might look at full-up sized rockets, and particularly, booster rockets. Solids, so we're comparing apples. The Delta rocket is quite interesting. It takes two sizes of booster rockets, in configurations of up to 9 strap-on solid rocket boosters. Then the shuttle, with two big SRB's; likewise, the Titan III with a pair of SRB's. The Ares I, which will be a single SRB stick and the Ares V, again two SRBs boosting a liquid biprop tank stack. Each of these configurations makes sense for its own application - but if a smaller diameter solid lifted a better mass fraction, you'd be seeing Titans and eventually Ares stacks that looked like Deltas - a whole bunch of smaller boosters around the mains. Smaller solid motors are much cheaper, easier to build, transport, store, maintain, and launch. They aren't more efficient. |
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//They aren't more efficient.// I'm not
claiming they're more efficient, just *as*
efficient as large solid rockets *in the
virtual absence of air resistance* (which
is a disproportionately greater
hindrance for smaller rockets launched
from ground level). As far as my
understanding of the physics goes, the
same laws should apply to smaller
rockets as larger ones. |
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| |
And yes, I did get the case-weight-ratio
relationship wrong - thanks.
[EDIT] or not quite. A quick think
shows that the transverse tension in a
cylinder will be proportional to the
diameter of the cylinder (and to the
pressure it contains). So, the thickness
of the casing walls remains in
proportion.
[EDIT AGAIN] In fact, if you consider an
SRB as a cylindrical pressure vessel, and
if the pressure remains constant, then
the circumferential force (that which is
trying to split the casing lengthwise) is
proportional to the diameter, whilst the
longitudinal force (that which is trying
to blow out the ends of the cylinder) is
proportional to the square of the
diameter. So, if your rocket is 10 times
smaller, your side walls can be 10 times
thinner and the end-wall or bulkhead
can be thinner still. |
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| |
Now, since the area of the rocket's skin
is proportional to the square of its
linear dimensions, it follows that a
1/10th scale rocket will have a skin
mass of 1/1000th that of the full-size
original; it will also hold 1/1000th the
propellant, so the skin mass: propellant
ratio stays the same. |
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| |
[Lurch] I just did some checks on
rockoons, and I maintain that smaller
rockets have comparable efficiency to
large ones, when launched at altitude.
Here's why. |
|
| |
A typical rockoon had a total mass of
100kg and carried a 15kg payload,
giving it a payload ratio of 15% (way
over the limit for a normal ground
launch aiming for orbit). Despite this,
they would typically make 75km above
the launch altitude of 25km (ie, apogee
100km). They were released at 25km
because of the need to maintain
communication for firing the rocket -
not an issue with modern telemetry, nor
if the rockoon fires automatically. |
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| |
So, reduce the payload ratio from 15%
to 2% (our 20g satellite, plus), launch at
50km rather than 25km (doable with
helium or with hydrogen), and you're
back in space. |
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| |
This is not meant to be a rigorous
argument (and yes, I appreciate the
rockoon went up but not around) -
merely to point out that
smaller rockets are more or less as
efficient as larger ones, when freed of
air resistance. |
|
| |
And I'm not taking your comments as
an attack - they are points well made
and are making me think. |
|
| |
Nice use of the subjunctive up there lurch.
Your comment on fins and how they work got me thinking. If the propulsive forse of the rocket were routed through symmetric skewed nozzles, could this spin the rocket for stability without too much loss of thrust? |
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| |
Can someone point me to some realistic formulas for calculation? [lurch]? I think all the stuff I've seen assumes low velocities, so the solid rockets have the torque, but not the top speed. |
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| |
Good math there, [MB]. I think we both missed a term at first, but in opposite directions. Thanks. |
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| |
[bungston] - re: canted nozzles - in theory, absolutely. (You wouldn't need that much of an offset, let the spin build up slowly, gradually taking over from fins as you go into thinner air.) In practice, uhh... I think it would be very difficult to have the two (or more) nozzles be identical, producing exactly the same torque vectors... maybe. I'd like to see it tried. |
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| |
Actually, maybe an interstage - say you have a first stage with fins. At or near booster burnout, fire the interstage which would just be a couple of small side-firing rocket motors mounted in the band connecting the booster stage to the second stage. After spin up, you can toss the part with the fins. |
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| |
Remember that you have to make a turn up there somewhere. Spinning your rocket is an ideal solution for an altitude only attempt. It's less excellent to have your little micronavigator going around at 600 rpm and trying to tell the rocket which way to head for the horizon. |
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| |
//I think it would be very difficult to
have the two (or more) nozzles be
identical, producing exactly the same
torque vectors// If you're transitioning
from fin-stability to spin-stability, then
let the fins create the spin - just have
them slightly helical. However, you
have the problem of directional stability
at the early stages of the launch, when
velocities (and spins) are low. |
|
| |
I thought it might be good to have the
rocket launched off a central rod which
runs up the centre of it (ie, the rocket
starts out impaled on a spike). Then,
you can set it spinning on the spike (in
any of several different ways) before it
launches. |
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| |
Point taken about the need to turn a
corner at the top. I need a bigger
drawing board to go back to. |
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| |
Not so much "turn a corner" - it needs to start off firing at a diagonal and, as it falls over to the horizontal at the top of the parabola, give a final kick of thrust to put it in orbit. |
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| |
Well, ideally you go straight up to get out
of the residual atmosphere by the shortest
route, then turn right. Also, the energy
needed to get a 20g satellite orbiting
(about 0.5MJ) is much more than the
energy needed to get it to alititude
(0.03MJ), based purely on calculations of
kinetic and gravitational energy. |
|
| |
So, the "final kick" is most of your energy
budget. |
|
| |
Been thinking about the final kick: a large number of satellites packed around some C4. One of them might go in the right direction. C4 detonation velocity just over 8000m/s. However, I guess this doesn't follow the spirit of the idea. |
|
| |
I think it's absolutely within the spirit of the idea. It's that sort of thinking that might make it happen. |
|
| |
Under the present rules (which are under
development), you have to specify *in
advance* which item is your satellite. This
to deal with the situation where, say, a
spent rocket enters orbit along with the
satellite, but the satellite can't be detected
(but the rocket can, for example because
of its size). So, alas, you'd fall foul of that
rule. However, you're definitely thinking
along the right lines. |
|
| |
[Ling], how do you keep from destroying the satellites? The bare minimum I can see is a reflector and I think this would destroy anything weaker than a block of metal. Wouldn't this work better with some kind of shaped charge? Or at least putting the explosive at the center of a tube and the satellite on one side. |
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| |
Also can people buy C4? I just assumed you can't. |
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| |
Send the (highly explosive) satellite up in a gun on a rocket under a hydrogen balloon. At a predetermined height the rocket will power out of the atmosphere on a pillar of flame, igniting the balloon in a huge conflagration behind it. Once out of the atmosphere, the gun will detonate, firing the explosive satellite into orbit where it will blow up and be visible from earth. |
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| |
The main advantage of this design is that it'll be a lot of fun. |
|
| |
We may have to go for a lower orbit (say, a
couple of thousand feet) if we want the
hydrogen balloon to conflagrate properly. |
|
| |
I love the C4 idea. The Ling Maneuver: massive redundancy with high explosive at the center and fingers crossed. I think that principle could be also used at earlier stages of the launch, and other aspects of the development of the project, and general nonrocket related life endeavors. I will give it a try here at lunch. |
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| |
Draft N-prize rules (slightly different from
those originally proposed) are on my
profile page for the time being. |
|
| |
We'll have figured out lots of ways to do it. Unfortunately we won't have picked up even a screwdriver. |
|
| |
--Taken from the rockeloonanoon thread, prolly better off here-- |
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| |
As someone who is unlikely to get a chance to compete, may I suggest that the final acceleration stage is most likely to be achieved with an EFP? |
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| |
-WARNING - watch out searching for the term EFP as a latge % of the use of them is by terrorists, the remainder being "genuine" millitary application -- </W> |
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| |
If you want ~20 grams going a really high speed, look at modifying an EFP to be the final stage in launching your load. An EFP weighing in at maybe 3kg can launch a >1kg mass at over 4km/s relative. That's a hell of a final boost. I'd say you could modify the paylaod of the EFP to have your package at the front, with a small bursting charge for separation once in orbit. Modern EFP's can be within several minute-of-angle accuracy <some testing required>. |
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| |
My guess would be a balloon, with a 1 or 2 stage rocket, with the final payload being an EFP with your package on the tip. making your hardware capable of handling the millions of G's is your problem. |
|
| |
I've always wondered how you would go trying to use explosive confinement to reinforce a barrel for extremely high pressure propulsion. Ie a pseudo-gun barrel surrounded in explosive blocks - and the "bullet" consists of a projectile (prolly with a sacrificial wear liner), and an extremely high power explosive propelling charge. Time the barrel enclosing explosives to explosively "reinforce" the barrel to support the ludicrous internal pressures for one, very high powered shot. Possibly the progressive collapse of the barrel and pressure wave could be used to constantly apply the driving force on the projectile. The limit here will be gas temperature, or should I say gas velocity, which will probably be the upper limit for how fast you can get the projectile to go. Unless, during detonation you are accelerating the entire mass of the "gun". In which this becomes analogous to a multi-stage rocket. Hmmm. A fair bit of crossover with explosively formed penetrator theory (EFP's). |
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| |
Once again, most of the technical stuff here will be rather highly classified, this time it will be that timing explosives to this precision is usually done for the sole purpose of detonating nuclear devices. but I'd like to know if it would work, or could be made to work. |
|
| |
//modifying an EFP to be the final stage in launching your load// Thanks, I've been trying to Google that all day based on a show I saw on the assignation of a president of the World Bank, or something, some time ago. All I remembered was a bicycle with a basket. In the basket was a remotely triggered explosive that turned a copper plate into a projectile of crazy velocity. |
|
| |
I don't know what is heavier, a small charge of C4 in a barrel made of Dyneema or a larger charge and no containment? It may not matter because I don't even want to know what it takes to get C4. My only hope is that if we drop the needed velocity down to 4km/s, we can use something that won't get me arrested. |
|
| |
The idea of creating the containment with multiple charges is amazing but way to complicated on this budget. It seems like a lot of little wires that could vibrate loose when this thing rips from 50km to 200km. I think it could work if done from the balloon. |
|
| |
Just an idea that's been floating about in my head for a few years, waiting for a use. And yes, if we include R&D costs, no way for under a grand, but if it's just materials costs, powergel is cheap and powerful, this could easily be ginned up for $1k. |
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| |
Government imposed permits/clearances notwithstanding. |
|
| |
PS I'd love some feedback on the confinement barrel idea, not sure if it's suitable for it's own thread. |
|
| |
Then again I just posted it |
|
| |
//assignation of a president of the World Bank// <snigger> blonde bombshell, doubtless... |
|
| |
I say do away with the weight restrictions altogether. If an entrant can get *any* object into orbit on the specified budget, and prove it, who cares if it weighs ten pounds or a nanogram? |
|
| |
And is there any relationship between the length of a railgun and the weight of the projectile? Could a ground based, single use railgun feasibly do this? |
|
| |
If we're looking at multi-stage launch systems, then our options are wide open. We can optimise each stage to suit the profile of each section of the launch. |
|
| |
Already we're discussing a two stage system with completely different technologies at each stage (balloon + solid/hybrid rocket). A third stage could use a completely different propulsion technology. |
|
| |
For example, the rockoon combination could launch a 2kg single-use cannon to elliptical orbit, then the cannon fires a 20g payload into a more circular orbit. |
|
| |
/edit/ Ah I see the Rockelloonannon [link] covers that example nicely. |
|
| |
Insert ideas involving railguns, Gauss cannons, tethers, mass-drivers, trebuchets etc below. |
|
| |
//I say do away with the weight
restrictions altogether.// Nope -
weight limit stays. As noted in the full
rules, you can use sabots, shielding etc
or whatever you like, but the final
orbiting device has to be <19.9999
grams. |
|
| |
//a ground based, single use railgun//
but, if it's single-use, you have to be
able to build it within the £999.99
budget (see full rules on my profile
page). |
|
| |
Just skimmed through "The rules", and I have a couple of questions: |
|
| |
1. How is the orbital height to be proved?
2. If the additional cost to launch satellite 2 was less than £999.99, then would that qualify? |
|
| |
Finally, I think the costs would be a big arguing point. Does it include import duties, VAT, trade discounts etc? Although if someone did it for 1100, I'm sure you would be so impressed that you would probably buy them a beer or two. |
|
| |
(Of course, the cost to launch S1 might be extensive...especially if it's a huge rail gun). |
|
| |
My biggest worry is making a left instead of a right, i.e.something goes wrong with the launch and it fires west instead of east. Then if you are unlucky enough, your tiny satellite will now have a short existence as a bullet which could strike another satellite at CRAZY impact velocities 14km/s and 4MJ of energy. |
|
| |
My biggest question is can a 20g satellite of undetermined location be detected from earth? I'm thinking everything could work perfectly, except the course is a little off so all the telescopes are pointed in the wrong spot to see it's signal. |
|
| |
//1. How is the orbital height to be
proved?// That is a very good question.
It will almost certainly require ground-
based observation, either telescopically
(eg, of a strobe or reflector) or radio-
wise/radarishly etc. It would almost
certainly be necessary to recruit the
help of others, but the budget for
detection is not included in the
£999.99. |
|
| |
/If the additional cost to launch satellite
2 was less than £999.99, then would
that qualify?// Probably yes. The rules
state that the cost of anything which is
used up must be covered, basically. So,
if you can build a very expensive railgun
or reuseable launch vehicle, and if all of
the costs (fuel/refurbishment etc, plus
the satellite itself) for the launch itself
come to under £999.99, you're fine. |
|
| |
// I think the costs would be a big
arguing point.// Yes, probably. That's
why I've got lots of "judges' decision is
final" clauses. Basically, after you've
completed your 9 orbits, if I said "here
is £999.99 in cash, do it again", you
should be able to. |
|
| |
//can a 20g satellite of undetermined
location be detected from earth?// Yes.
20g will easily accommodate a simple
transmitter, and the power delivered to
earth will be way bigger than that
detected by radioastronomers, I think.
Or you could have a small strobe-light,
again easily detectable. Someone also
suggested radar reflectors of mylar film. |
|
| |
The main problem will be in recruiting
help, and in knowing where to look. I
imagine you'd want some more
powerful telemetry on your rocket (if
you use a rocket), so you at least know
the direction and velocity of your
satellite at the moment it's released into
orbit. |
|
| |
So wait, if reusable costs are not counted, then we may want to think about a hypersonic RC launch vehicle. I had toyed with this idea at the beginning, but discounted it as too expensive. |
|
| |
So all I have to do know is build a scale model SR-71 or Aurora to launch my LEO insertion rocket off of. |
|
| |
//we may want to think about a
hypersonic RC launch vehicle// By all
means. As long as you recover the vehicle
intact, and as long as the cost of fuel and
any necessary refurbishment, plus the cost
of the satellite, are covered by £999.99,
then by all means. |
|
| |
I found a excellent link on the topic called "Are Amateur Orbital Rockets Possible?" Has lots of great other links included. I am now debating between the hybrid (N2O/PVC) rocket (SpaceShip One) and the LOX/kerosene (Apollo) path to orbit. |
|
| |
Very nice link, Mr. QED - many thanks.
Especially interesting is the note to use
existing satellites to help with telemetry
- I presume this offers a number of
options. |
|
| |
Note also that amateur rocketry to date
has been hampered by the relatively
large budgets which people are
prepared to sink into these things. A
much smaller budget should offer a far
better chance of success. |
|
| |
The N-prize site should be up in a week
or two - watch this final frontier. |
|
| |
Nice work on the website. |
|
| |
Nice website, and I know I am supposed to email you questions, but I want to have this one here for clarification. |
|
| |
Are reusable parts included in the £999.99? |
|
| |
So for example, I build a $3000 rocket, that launches from a $2000 balloon, that reaches 100km, fires a cannon to launch the satellite which orbits 9 times. My rocket, balloon launcher and all it's parts minus fuel & lifting gas and satellite are recovered. I can then take all those parts add less than £999.99 worth of fuel, lifting gas and satellite and repeat the event. Is that legal? |
|
| |
Thanks to [wagster] and team for the
website - see the link on the site. |
|
| |
No, the £999.99 only has to cover non-
reuseable parts. Basically, you should be
able (if asked) to repeat your launch
without spending more than another
£999.99 - see the full rules on the n-
prize site. |
|
| |
Nice website. You might want to be careful about implying that you actually have 9,999 pounds to give away. |
|
| |
- unless, of course, you actually do have £9,999 to give away.
Is there any rule about how high the satellite has to orbit? If not, then someone will enter a helium balloon tied to a bit of ballast, which will float a few metres above the ground for nine days in geostationary orbit around the Earth. |
|
| |
No, that won't work, there is a 99km altitude minimum. |
|
| |
// implying that you actually have 9,999
pounds to give away.// I'm not implying
that I have £9,999.99 to give away. I have
£9,999.99 to give away. |
|
| |
//No, that won't work, there is a 99km altitude minimum.// |
|
| |
And a rule that says that the organisers can close off any loopholes that run against the spirit of the competition at any time. [Maxwell] may have put his money where his mouth is, but he isn't getting stitched up. |
|
| |
May I request that the Question (by Jupiter), in homage to the n-prize's origin, be amended to "Shirley it's impossible?", and the answer have the following addendum: "(and stop calling me Shirley)" |
|
| |
Actually, I think I rather like that. And
perhaps the graphic could have a black
rectangular slab, with sides in the ratio
1:4:9, orbiting around it. |
|
| |
The N-Prize is discussed in the New Scientist's space blog. |
|
| |
By the way, very neat website! |
|
| |
Excellent, getting picked up by New
Scientist. Let's hope this brings some
imaginative entries. |
|
| |
Thanks! (And thanks to Wags at
picture&word for the site.) |
|
| |
It also made it into New Scientist print
edition (brief mention in last week's
issue), and I've got an invite to go on
The Space Show (www.the
spaceshow.com) - an enthusiast radio
station (date to be decided). |
|
| |
And special thanks to everyone here for
bringing this about. I'll look forward to
meeting some of you at the inquest. |
|
| |
My pleasure. Can't wait to buy the New Scientist tomorrow. |
|
| |
About 1 column inch, bottom right corner,
page 7 I think! |
|
| |
How on Earth did I miss this?!
Inspiring, Educational, Slightly Barmey and a Wager to Boot!
Best of British to All and nice website to [wags]. |
|
| |
Not being a rocket scientist myself, what happens when the satelite does a few orbits but in a direction that's way off kilter from a great circle route? Does it correct itself, do some kind of odd spiral pattern, or what? |
|
| |
Nevermind, it probably has to do a great circle route because something else would require side thrust. |
|
| |
Also, who gets to explain when we knock down a telecom satelite? |
|
| |
If we knock down a telecoms satellite then
(a) it'll mean we've considerably exceeded
the requirements for the N-Prize and (b)
they won't be able to phone up to
complain. |
|
| |
... and (c) they will kidnap you, steal your plans, and pour all their money into them. |
|
| |
I was reading an article on rocketry and came across this: |
|
| |
"The agency is also concerned that large rockets could be used as weapons. But weapons experts say it is doubtful that the rockets could be significant threats because they do not have guidance systems, which are prohibited by federal law." |
|
| |
So, will travel costs to a non-U.S. location be a part of total cost? <link to full article> |
|
| |
That's interesting! Fortunately, travel costs
to a non-US location will be negligible for
all participants, apart from those living in
the US. |
|
| |
Incidentally, you're all invited to drop in to
the N-Prize group (linked under "Contact"
on the N-Prize site). |
|
| |
That's minor, we just found out that GPS stops working above 60000 feet and a specific speed. Government regs again, literally keeping us down. You can leave US, but making your own GPS is tougher. |
|
| |
the thing about GPS is that devices
made in the US (and maybe elsewhere)
are deliberately restricted in altitude
and speed. The high-end chips that
include onboard processing may be
hackable; earlier chips may perform
only the core functions and may
therefore not be crippled. |
|
| |
But, if push comes to shove, there are
plenty of ways to tell where you are. |
|
| |
[Blatant elf-promotion] I'll be on radio in
about an hour (9:30am pacific daylight
time) talking about the N-Prize, and will
try to mention the HB. It's called The
Space Show, and it's at
www.thespaceshow.com |
|
| |
I'll have a listen to that. |
|
| |
On the subject of GPS, I wonder if Galileo would be more useable for our purposes? It probably won't be ready in time. |
|
| |
Heard that!. Sounds like you are going great guns. I may even buy the T-Shirt!. |
|
| |
Thanks for the link, Xavier, and thanks to
Robert Goldsmith for the original article
and the slashdot. We've now got five
teams signed up, with another four on the
way - making a highly appropriate nine
teams. I'll try to encourage entrants to put
a small croissant logo on their satellite,
with Jutta's permission. |
|
| |
It'll get a bit baked on reentry. |
|
| |
Getting Worried Yet, [MaxwellBuchanan]?
Good Work though! |
|
| |
Terrified, more like. But not about having
to give away the prize money - I'll be more
than delighted to see someone claim it.
One giant leap for a man, one small step
for mankind. |
|
| |
£999.99 will barely put a thing into space today, let alone orbit. |
|
| |
How about: if the best contestant is over budget, give them the award anyway, but subtract $2 from the prize for every $1 they went over budget? |
|
| |
Getting a roll of quarters into orbit for £1000 would still be pretty amazing. |
|
| |
How about: if the best contestant is over budget, throw a big party for all those who gave it their all. |
|
| |
jcatkeson: I'll bet you £9,999.99 that
somebody wins the prize, within the rules. |
|
| |
God I hate fuckers who post advertisements in forums and other user message board type websites. |
|
| |
What the hell....is this getting baked???? saw it on slashdot yesterday and knew I'd read it somewhere before... |
|
| |
Would it be too much to ask for it to be croissant-shaped? Probably. It's all got a bit serious now, hasn't it? |
|
| |
[Max] Has anyone given you a rough estimate of their launch date yet? I'm getting quite excited by this - and I want to be able to marvel at the economy and cleverness that will be required by the winning entry. |
|
| |
//God I hate ____ers who post
advertisements// huh? |
|
| |
//What the hell....is this getting baked?
???// Yep. |
|
| |
// It's all got a bit serious now, hasn't
it?// Nope. |
|
| |
//Has anyone given you a rough
estimate of their launch date yet?// No,
not yet. My guess is that we're looking
at at least a year before any launch
attempts (though I may be wrong). I
suspect the winner will have to develop
a lot of new hardware, so I'd be
surprised if we get there before 2 years
from now. |
|
| |
However, all entrants need to keep me
posted on launch plans, so I'll have
some warning and will let people know.
Check the Google group also.. |
|
| |
After this of course we'll need handkerchief-sized solar sails and then we can rule the solar system. |
|
| |
See: Another Mad Scheme[Link], I was originally going to call it the 'X-stremely Small Prize'. |
|
| |
I was surprised to discover that a few-
hundred-milliwatt transmitter is easily
pick-uppable from earth, and such a
transmitter can easily be included within
the weight restrictions. |
|
| |
//a few- hundred-milliwatt transmitter is easily pick-uppable from earth// - no, get one of the Martian ones. They're much cheaper. |
|
| |
//a few- hundred-milliwatt transmitter is easily pick-uppable from earth//
You could boost prize funds by selling tinfoil hats to the weak-minded, as N-prize countermeasures. |
|
| |
//I know you are quite set on the
£999.99 prize, but wouldn't it be
interesting to put a button on the site
to allow people to donate extra money?
// |
|
| |
The prize is actually £9,999.99;
£999.99 is the budget for each launch.
I'm reluctant to increase the prize, since
this would attract sane people.
However, I have considered allowing
"charity co-sponsoring" - eg, maybe
Virgin puts up £999,999 to be donated
to a list of 9 charities if and when the
N-Prize is won. It'd be good to raise
some money for worthy causes (like,
maybe a new burns unit at some
hospital....). |
|
| |
[MB] In reference to someone or anyone winning this prize, I will admit, I would have said no. It seemed like asking too much for too little reward, but I have since revised my thoughts. Or to be exact I have revised my view of people. Is it just me, or were you also shocked to find out that there are people out there who have half-built aerospike engines in their basements? NASA isn't even sure they will work, yet a private entity has most of one? I rarely meet scary smart people in real life and have met a few here, but the N-prize entries have rocked my ideas on reality. I mean one isn't even worried about propulsion, really just telemetry, does that surprise you? |
|
| |
I wasn't surprised at the level of
enthusiasm in relation to the prize money
- I imagined from the beginning that
people would go for this for the sheer hell
of it. |
|
| |
What did amaze me, though, was the level
of commitment and expertise that people
have brought to this. I'm still amazed by
this today. |
|
| |
Is there a way of using gravitational acceleration? An object might not have to get to orbital velocity under its own power, just to a velocity which would enable it to "fall" at an angle which would allow gravity to do the last bit. Meteors do that sometimes. |
|
| |
That sounds like the Douglas Adam's principle. I think you mean use extra elevation with a relatively small 'horizontal' velocity, and then throw yourself at the Earth and miss due to a sling-shot type effect. |
|
| |
//Is there a way of using gravitational
acceleration?// |
|
| |
That's how 'regular' orbits already work.
You throw yourself sideways so that, by
the time gravity has pulled you back
down, the Earth has curved away from
you and so your no closer to it. |
|
| |
Of course, you could use a gravitational
slingshot involving another planet. If
you could swing by Mars, you could
pick up a huge additional velocity if you
got things right. However, you'd have
to get there first. Alternatively, if we
could get a tame black hole up there,
you could use that. |
|
| |
I understand that elliptical orbits are based on the principle of missing the ground, but if an object is falling slightly below orbital velocity, it will accelerate, assuming no drag. That means that it will reach orbital velocity, but it would have to be at the correct angle to avoid colliding with the planet. The point i'm making is that gravity can be used to accelerate an object, and so maybe the slingshot effect can be used in the upper atmosphere if it's at the right angle. |
|
| |
What i've ended up thinking is a rockoon which uses its own hydrogen, is streamlined and contains a two-stage cylinder. The first stage is a Gauss gun, the second a solid fuel rocket, or the other way round. Each stage - rockoon, Gauss gun, solid fuel rocket - slants closer to the horizontal than the previous one. Then, a tiny centrifuge launches the satellite, then the fog of a humanities education descends on my mind and i think vaguely of a slingshot principle which accelerates the satellite using gravity. |
|
| |
//were you also shocked to find out that there are people out there who have half-built aerospike engines in their basements?// |
|
| |
//One giant leap for a man, one small step for mankind.// |
|
| |
//gravity can be used to accelerate an
object, and so maybe the slingshot
effect can be used in the upper
atmosphere if it's at the right angle.// I
see your argument, but I'm pretty sure
that whatever you gain from the fall you
will have already paid for in getting it
up there in the first place. I suspect
that the fundamental problem is that
the projectile and the earth both start
out with the same velocities. |
|
| |
I did think there'd be some kind of conservation of energy problem, but i didn't know what it would be. |
|
| |
Then again, and this is probably where i leave the shores of sanity, the orbital velocity of this planet around the sun is greater than its escape velocity, so were there a way to use that fact without leaving the atmosphere, it'd be nice, wouldn't it? |
|
| |
Maybe you could just hang around until an asteroid hits us and hope it pings a coin into orbit. |
|
| |
(I think that) unless your speed was greater than escape velocity to begin with you would end up being captured by your slingshot (either in orbit ... or a crater) |
|
| |
//the orbital velocity of this planet around
the sun is greater than its escape
velocity// You mean that the orbital
velocity of the earth around the sun is
greater than the escape velocity of an
object from the earth? Yes, but that's not
the point - all that's relevant is the velocity
of the satellite and the earth relative to one
another. |
|
| |
I see that, but the thing is, it seems a shame that that fact is completely useless. |
|
| |
Quite so. Even worse is the fact that we,
along with our sun, are whizzing around
the centre of the galaxy at a truly
preposterous rate, and our galaxy in turn
is doing quite a respectable turn of speed
with respect to the centre of the universe,
yet it's bugger all use to us. |
|
| |
Stupid question here; if the Sun was directly above the launch would its gravitational attraction make it any easier to escape the Earths gravity well, or would the effect be negligible? |
|
| |
That is a very good question. I can give
plausible answers in either direction: |
|
| |
1) The effect will be small but definite.
Just as the sun contributes to tides by
lifting the mobile part of the earth's
surface (the water) toward it, so there
would also be a small but definite boost
to a spacecraft. The same would be
true on the opposite side of the earth,
just as a second high tide occurs there.
But the greater overall effect would
come from the moon. |
|
| |
2) The effect will be non-existent. Yes,
the sun (and the moon) pulls things
toward it. However, it pulls equally on
the earth and on the rocket (mass for
mass) and therefore there'll be no net
effect. |
|
| |
Now, the problem is to decide which
answer is correct. |
|
| |
The launch vehicle is orbiting the sun at the same speed as the earth. In this orbit the inward gravitational pull is balanced out exactly by outward acceleration. If you want to take advantage of the gravitational pull of the sun, you will need to decelerate. |
|
| |
You might argue that if you launched in the daytime you should launch against the direction of earth's orbit so that your launch velocity will be subtracted from your orbital velocity around the sun. This will decrease the outward acceleration of the orbit and allow some of the pull of the sun to take effect, moving you away from the earth. Similarly, if you launch at night you should launch with the earth's orbit, so that your launch velocity is added to the solar orbit velocity and you accelerate away from both the sun and the earth. |
|
| |
I expect there are more important factors though. |
|
| |
//2) The effect will be non-existent [etc.]// |
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If we go with hypothesis 2, could we not argue with equal force that the moon pulls equally on the earth and on the sea (mass for mass), and that tides are therefore caused by nereids playing tug-of-war? |
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If so, would this be a point against hypothesis 2 or in favour? |
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So we are looking to be in the umbra of a total solar eclipse (moon and sun directly aligned), preferably close to the equator, at the perihelion, before 2011. <rushes off to check mayan calendar>. |
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Mmmm, I'd have to go with (2) because like wags said we are already in orbit around the sun.
The moon though, being in orbit around us might give a bit of pull. |
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What about a spring tide (i.e. perigee) close to perihelion? Teeny, teeny differences. |
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[EDIT!!!!! date changed to 15th
November!! Invite is still open if
anyone's in the UK.] |
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If anyone is likely to be in, near, around
or
in the vicinity of Cambridge (don't ask
me
which one!) on Sept 27th [NOW 15th
NOV] , I'm organising
an N-Prize dinner at one of the
colleges.
There's likely to be room for one or two
more and, since the whole thing started
here, I'd be honoured if any of you
would
care to join us. Dinner and drinks are
on
me - first come, first served! Email me
at
info@n-prize.com if you're interested. |
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At the risk of gratuitous churning, just a brief update: there
are now 15 teams signed up and, although the first
impressive injury has yet to be suffered, hardware is being
built. Some pics, links, news etc on the N-Prize site and on
the Google group linked from there. Thanks again to the HB
for gestating this idea. |
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First time I've seen this. Good luck with the croissantnic thing. |
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SO impressed! Kudos [MaxwellBuchanan], [jutta], Halfbakery... |
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Kudos not to Maxwell Buchanan, but to Jutta, to Wagster (for
building the N-Prize site and making it real), and above all to
the teams who have devoted huge amounts of thought,
effort and money (and, in due course, eyebrows and fingers). |
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It's good to know that this Forum (Halfbakery) is relevent to the world and matters... |
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Whoa there! The N-Prize organizers deny all claims of
relevancy! |
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I'm enormously impressed, [MaxB]. And you've got two teams from New Zealand - very interesting. |
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Thanks [hippo]. New Zealand probably has the highest
density of N-Prize teams after the UK! Kudos to the NZ
teams (one kudo each). |
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I make New Zealand (pop.: 4,173,460 - N-Prize teams: 2 - N-Prize teams per 10m people: 4.79) to be about 10 times as enthusiastic as the UK (pop.: 60,943,912 - N-Prize teams: 3 - N-Prize teams per 10m people: 0.49) |
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Hippo, I bow to your analysis. |
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Wow this looks like fun! Can the HB put forth a team? We
could agree on how to construct and launch the rocket
online, then find a 'baker with the wherewithal to actually
build it. The prize money, after replenishing said 'baker's
finances could go to charity |
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Are any teams getting close yet? |
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I just put a Shekel on a bean sprout. I promise to notify as things happen. |
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(clever weather balloon space story linked) |
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[up on cloud 9] BTW, there is one unofficial HB N-Prize Team, though it's almost just me, Team Daedalus and I'm looking for help. Weirdly enough there is also another team which is baking an idea I posted here. Team Prometheus is trying to bake my "Rockeloonannon", though he honestly doesn't seem to have read it. I guess insane minds think alike. |
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[MisterQED] - I'd offer my help, but my only real use would be
helping with construction [probably not even then], and
seeing as
you live on a different continent that's not really possible. |
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Actually my plan is completely modular and centers around small complex objects linked together with large low tech objects, with the idea that one person could make several copies of one system and another could make several copies of another, etc. and once you get enough systems together, everybody exchanges and builds their own rocket. Sell the parts after as a kit. The key is to concentrate the tech with an eye for mass production. |
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The keys are a small pump driven bi-prop rocket (similar to Project Mockingbird), an optical/magnetic guidance system (similar to those developed for HARP rockets) and a homemade zero-pressure balloon assembled using low cost plastic sheeting heat welded together in the shape of a sphere and filled with hydrogen from water electrolysis. |
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"Making wings so everyone can fly" |
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<Behind on responses - have been in San Diego and in the
air for the last 24 hours> |
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[Germanicus] nobody has an imminent launch of a full
mission, but several teams have some hardware already
built. Most of the teams have their own websites with
updates, and these are linked (under "Teams") from the N-
prize site. |
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[humanzee] No offense taken :-) I know David
Livingstone said he drops by the site sometimes, but
whether he has an account I'm not sure. |
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Arising from another HB idea (see link), I wonder if a glorified
spud-gun, say 100m tall, would give a useful boost to an N-
Prize rocket before its own motors kicked in? The gun itself
is ground equipment, so its construction cost doesn't count
towards budget. Of course we are not going to reach orbital
heights this way, but it would be a nearly "free" boost for an
otherwise conventional rocket. |
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Before I checked the link, I thought the other idea you were referring to was the Fuel-Air Gun. I pictured a big vertical pipe, filled with diesel and air, with the spacecraft dropped in the top by crane. |
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//I wonder if a glorified spud-gun, //
"Spuds in Space" |
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// I pictured a big vertical pipe, filled with diesel and air,//
Yes, that'd basically be it. The aim would simply be to give
the rocket a headstart. I don't know what kind of velocities
you could get from the gun, but maybe half a kps; a small
part of the total velocity needed, but it's "free". |
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Not so much extraterrestrial as subterrestrial? |
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I never thought of my idea being use for the n-prized but I suppose the principal is the same. What if you launched your rocket from a tube that was sealed by the rocket itself, so that the exhaust gases build up pressure behind it to give an added boost? I'm no rocket scientist but if you could make the tube long enough & strong enough this might work. |
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That sounds like a reasonable idea. |
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I know that the secret of rocket design is to get the
exhaust velocities right so that as much as possible of the
energy of the exhaust gases is translated into thrust, but I
don't know the actual efficiencies, and your suggestion
might help. |
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However, if you have the tube, why derive the
compression from valuable (ie, carried) rocket fuel when it
can come from cheap (ie, ground-based) fuel? |
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I have been thinking long and hard about these so-called "invisibility cloaks". An arrangement of surfaces that direct certain waveforms around an object as if it were not there. (theoretically they have been applied to shore breaks). To me there exists the posibility of a structure, not tubular or cylindrical, that would deflect the resultant forces of a launch, into the most verticle plane. So far the geometries of these "invisible" structures apply only to microwave light (or more accurately, have been applied to microwave wavelengths) The studies want to drag them into the visible spectrum, but what if we go the other way, into sub/super sonic wavelengths. |
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I would wager another one of my delicious Macon hats (previous one still waiting to be devoured) that you could get great effeciaency from such an arrangement. The structure would be as energy complex to arrange as a stand alone cylinder x Km tall, but may add boost not by containment but also by re- addition of wasted forces. |
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You all are talking about HARP, firing a rocket from a cannon. It is cool and it works, but the cannon is no potato gun because the downsides are not overcome until you put some real push to the rocket. |
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One of the issues with shooting a rocket out of a gun is dynamic pressure. |
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Notice during a space shuttle launch they actually have to throttle the engines back at a certain point, while they go through "Max Q"; then at about 70 seconds after launch they're through that part and can go back to full on. (That "Roger, go at throttle-up" call that still gives me a little shudder every time I hear it) |
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Anyway, dynamic pressure on your rocket's airframe increases with velocity (I can't remember whether its the square or the cube, but it's one of those), and decreases as the air gets thinner. You'd think that it's just a problem for the Shuttle, with its weird shape and interflecting aerodynamic surfaces, but it can play havoc with an aerodynamically sleek & simple machine as well. For example, if you are old enough to remember the Saturn V launches, you may remember that it launched straight up. It was a long way up before they started to turn downrange. The point was to get above as much air as possible before the velocity got too high. |
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The Shuttle does its roll & tip manuver almost as soon as it clears the pad - it's actually a much more robust airframe. It's built to handle re-entry, which the Saturn rocket wasn't; and as rough as launch dynamics can get, they're nothing compared to re-entry. |
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Shoot your rocket out of a tube, and you get a very high velocity down in the thickest part of the atmosphere. |
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Does that mean you'd get away with a weaker (and cheaper) airframe if you launched from a weather balloon? |
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Hippo - yes, which is the basis of the "Rockoon" (rocket
launched from a balloon, above most of the atmosphere) -
see earlier discussions. (The main reason for a rockoon is
avoid the high drag and hence reduce fuel usage in punching
through the lower atmosphere, but I guess stress on the
airframe is another consideration.) |
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Yep. I fear we're going to end up with a pretty darn big launch platform, though... |
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(Actually, I think there's another reason to use this from a high-altitude launcher: up where the air is thin, you gotta be going at a pretty good clip before your fins start doing anything worthwhile. Shooting out of a tube means less time in a potentially unstable flight mode.) |
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has the thought of using the contents of the LTA launch platform as fuel been considered? As the vehicle departs the platform it could draw the contents of the lift vehicle through a hose into a special housing that fell off when the distance between the rocket and the platform was great enough. This could deplete the platform enough to allow retrieval. |
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You should contact the people in the link I posted,
they might be interested in becoming a team. |
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Curiously I had this idea many moons ago: for the 50th anniversary of Sputnik to launch, via mass driver, a 1g payload to duplicate the 'beep-beep' for an orbit or two. Then state of the art made such a transmitter doable. The problem, I'm told, is length of antenna but this isn't insurmountable. My problem was getting access to enough electric power to juice a launcher; it's non-trivial. |
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