Science: Space: Launch
Hawaiian Launch Track   (+2, -4)  [vote for, against]
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"Mauna Kea is the tallest mountain in the world when measured from base to summit, since its base is located on the seafloor about 19,000 feet (5,800 m) beneath the surface of the Pacific Ocean, bringing its total height to about 33,000 ft (10,000 m)" - wikipedia

It is also:

* Closer to the equator than Florida
* Part of a nation with an established space program
* Well serviced by sea transport infrastructure
* Already home to space science installations (telescopes)

All of which makes it an ideal location for a rilly, rilly long linear accelerator.

The longer one's linear accelerator, the lower the G-force that needs to be applied to your payload. Hence the less high engineering art that needs to be applied to the survivabilty of said payload. Being launched from a short track is akin to being shot from a cannon.

A ten kilometer launch track can reach low earth orbit with an acceleration of a mere 360 G [calculations follow]. Add in the slope of the mountain and you probably have a 20 to 100 km track to work with, and a linear-proportionally lower G rating.

So: a tunnel beneath the sea stretches out to the west of the Hawaiian islands. Said tunnel contains [launch technology 1]. This mates with the high velocity stage [launch technology 2] which traverses the remaining 4.2 kilometers (vertical) to the mountain's summit.

Of course I realise that engineering reliable structures at depths of ~6km is non-trivial. But such trifles need not concern us overly here. This is SPACE we're talking about people. Hang the expense, I say.
-- BunsenHoneydew, Feb 29 2008

Mauna Kea
[BunsenHoneydew, Feb 29 2008]

For [MaxwellBuchanan]: Hawaiian Lunch Truck. http://tastyisland....g-hula-lunch-wagon/
Cheese, yes. On the cheeseburgers. [Amos Kito, Mar 01 2008]

Possible but non-exclusive propulsion technologies follow. Other examples may be found littered generously throughout these pages.

[stage 1]: One proposed Russian private enterprise launch system I recall being bandied about in the dying years of the last century involved a vertical launch tube sunk to some depth in the ocean. Evacuating this tube of water and then suddenly re-admitting it from the nether region creates an explosive compression shock in the air betwixt brine and craft, hurtling it propitiously heavenwards. With the pressures extant at 3,000 fathoms, such an effect should be prodigious.

[stage 2]: railgun or maglev.


Orbital velocity = 8km/s
Initial velocity = 0

-> average velocity (whilst on track) = 4km/s

Length of track = 10km

-> time on track = 2.25s
-> acceleration = 8000/2.25
= 3 555.55556 m / s2
~ 360 G

Length of track = 100km
-> acceleration = 36 G
-- BunsenHoneydew, Feb 29 2008

-- WcW, Feb 29 2008

Rilly? Does it have small channels eroded into it?
-- WcW, Feb 29 2008

No doubt it does. It would be fortuitous indeed to find such a rill extending due west with the degree of linearity required, but barring such happenstance we can safely say that such erosion features represent mere geoengineering obstacles that trifle on the scale of such a project.

No rilly.
-- BunsenHoneydew, Feb 29 2008

If you landed in the same site it would truly be a splashdown.
-- normzone, Feb 29 2008

So, let's build a very long structure that will require enormous stability and fine tolerances and in a volcanically active area. I don't think so!

And we don't have the technology to build much of anything 6 km deep in the ocean, let alone launch facilities for space ships. so this is very much in the realms of wishful thinking.

But more importantly, the idea of building long launch ramps for space ships is not the least bit new.
-- DrCurry, Feb 29 2008

//Mauna Kea dips out//
That’s a shame because...

I wanna go back
to my little launch track
in Kealakekua Hawai'i,
where the humu-humu-nuku-nuku-apua’a
go swimming by.
-- Amos Kito, Feb 29 2008

6 km down, s/he could just let the water in, pushing the rocket up the tube like a cork. How fast it could propel the rocket would depend on the laminar flow of water in a tube.
-- DrCurry, Feb 29 2008

This would be the ideal circumstance for the steam launch facility I just linked up. You know, I think Mauna Kea was mentioned in that idea. I will check. I will note that Hawaai also has:

1: Water, which is the principal ingredient in steam, 2: Hot lava, which is very hot. 3: Poi, which is a nice shade of purple.
-- bungston, Feb 29 2008

Hang on.

Orbital velocity is 8km/sec, as has been pointed out.

However, if something comes out of the end of this tube at 8km/sec into air, then (a) it's going to get very, very hot and (b) it's going to slow down a lot.
-- MaxwellBuchanan, Feb 29 2008

This would be much more workable as a Hawaiian Lunch Track. I envision a luau-type setup, but streamlined. We can keep the mating with the high velocity stage, if it is consensual.
-- bungston, Feb 29 2008

Could there be cheese?
-- MaxwellBuchanan, Mar 01 2008

The 0 - 8km/s acceleration would be less if the tube was a spiral, but I think the Gs due to cornering would negate any benefit.
-- marklar, Mar 02 2008

//if something comes out of the end of this tube at 8km/sec//

It doesn't have to. There could be a traditional rocket propelled third stage, which would again lower the acceleration required over the length of the track.

[UnaBubba] I had a quick squizz at Mount LamLam and the Marianas Trench. There seems a fair bit of distance and undulating terrain between them. A single volcanic cone seems much more useable.
-- BunsenHoneydew, Mar 04 2008

I too read this as "Hawaiian Lunch Truck". Now my mind dances with thoughts of roasted ham with pineapple chunks.
-- ed, Mar 05 2008

random, halfbakery