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Ok... I was thinking the other day about this idea, I
wondered... How about a Super Hubble Space Scope...
here is how it works... you send out a new hubble... this
hubble is half the size of the present hubble and only
consist
of a high definition CCD, just like the hubbles... you dont
have
to worry about special power systems becuase my idea is
two-
fold...
Ok, here it is... (note: you would have to get into deep
space
to use it...to avoid impacts and debree) My idea is a giant
inflatable parabolic lens shaped balloon...
And I Mean Giant!... since you wouldnt really need much
pressure to inflate a balloon in a vacume And the shape of
the
lens balloon could be altered by varying the pressure inside
the inflatable lens... the lens would be perfect becuase its
a
balloon... and its cheap and you could bring a few for
redundancy if one did happen to get hit by a impact... Also
I
am sure you could use it to generate energy using a interior
solar cell... you would have to close the CCD to protect it...
but in this way... it would be nearly perpetual in its
operation... When I say huge lens... Imagine as big as you
can...
And since these Probes would be so cheap and redundant
you could launch multiple Super Hubbles and join them
together to creat one truely giant eye...
what do ya think...
NASA to boldly go
http://www.newscien...s.jsp?id=ns99992955
Recently announced NASA idea to put telescopes at the Lagrange points in Earth-moon orbit. [krelnik, Oct 04 2004]
Annotation:
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Spelling police: debris, not debree; vacuum not vacume, because, not becuase, truly, not truley.
What happens when a meteorite hits the balloon? |
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The lens, being filled with gas, rather than glass, would have little ability to refract light (a refractive index close to that of a vacuum). And it would be impossible with a balloon to maintain a true shape with the sort of fine control required in a telescope's optics. |
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let me define what I mean... |
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the blow-up lens would have one half of the lens shape
silvered on the outer rim and have transparent center
and the opposite half of the balloon would be silvered in
the center and transparent outer rim... creating a huge
variable shape parabolic telescope... |
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I probably should have included that... |
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If it's in deep space, how is the solar power element going to work? |
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Not that my skepticism should burst your balloon, but I would be surprised if a material could be found that supports both inflation and the kind of optical fidelity needed to make this thing work with usable results. Specifically, I doubt that the light once it had passed through the first surface of this rig would be in any kind of condition from which to capture a usable image. |
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Since the Hubble's lenses and mirrors had to be ground in such a way as to compensate for contraction in the cold of space I'm not sure how you're going to cope with fine optical adjustments on this thing. Assuming you have it close in to the Earth, where it will remain inflated, a little solar storm will heat up thegas enough to alter the focal length of the lens. The weight of the CCD and apparatus will distort the gas bag. |
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If you move it further out into space you run into a rather more intractable problem... What gas are you using to maintain inflation? |
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If you put a physical object into space, it will reach a temperature that depends on how efficiently it absorbs and emits radiation and on what heating sources are nearby. |
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For example, an object that both absorbs and emits
perfectly, put at the Earth's distance from the Sun, will reach a temperature of about 280 K or 7 C. |
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If it is shielded from the Sun but exposed to interplanetary and interstellar radiation, it reaches about 5 K. |
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If it were far from all stars and galaxies, it would come into equilibrium with the microwave
background at about 2.7 K. |
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Neither of these last two is sufficient to maintain any meaningful internal pressure, as the gas will slow almost to a complete halt and liquefy, then freeze solid. |
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Sorry to see your balloon shrivel up like raisins in the cold of deep, deep space. |
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what ub said; but also the fact that it would take *ages* to get there (interstellar space--i take it you mean outside of our galaxy; the nearest star, for example, proxima centauri, is 4 ly away and we can't travel anywhere near the speed of light) and then it would take years for the signals to get back to earth. also, you'd get all sorts of refraction issues because of cosmological redshift (relatively small, i suppose, if you kept it close by), interactions with interstellar dust, hubble shifts from earth's motion, etc... would make clear images difficult i think.
... interesting idea nonetheless--but practically probably non-workable. |
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UB - If there is pressure for it to burst - there is pressure for it to work. |
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You haven't actually finished your first year of your Bachelor of Mad Science yet, have you Neelandan? |
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A little knowledge can be a truly dangerous thing. |
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I hear NASA have stopped talking to Deep Space One. |
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[Rods Tiger] - That would be debrie |
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<pa>more appropriate ending: "... to deflate your balloon." It does seem weird to see you go on and on about the gas pressure vanishing, and then say something that requires high pressure.</pa> |
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There actually is a serious proposal to put a telescope quite a long ways out into space, well beyond Pluto's orbit. If I recall right, at about 530 Astronomical Units (one AU = distance from Sun to Earth), the Sun's gravity acts as a focal point ("gravitational lensing"). Putting a imaging system at that point means that you are using a "lens" that is something like a million miles wide. |
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Is that big enough for you? |
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Peek-a-boo, I see you, UB. |
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Interesting idea, wrong approach, though. |
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Instead of the lens, use a giant mirror. All you'd need is a reflective coating. The curvature does the rest. |
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As for irregularities in the mirror, wouldn't a huge aperature mean that the usual optical tolerances (ie a wavelength of light) would be thrown out? Would deformations in the mirror of a few feet be allowable as the photons coming from the flaw would be minute compared to those coming from the rest of the mirror? |
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Side note: Interferometry can do this much cheaper and be redundant. There are plans to put arrays of telescopes in orbit around the sun, each with a relatively small resolving power. But when combined, they act as a single massive lens. |
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I migrated a very similar (and more recent) idea about m2p2 to this category. Started out as a halfcrumb on terraforming. I don't see gas freezing as a major problem--in fact the reflective qualities of a pneumoastromirror might be much improved by a gas that crystalized in a uniform way...As for the distortion issues, I suppose you could have a mirror that flopped all over the place so long as you kept track of its every twitch by radar and combined everything together in the right order. The point about lots of small telescopes is a good one. Maybe the definition of small will inflate, however. |
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I'm going to have to go with [rapid transit] here, combining smaller telescopes into one bigger telescopes is the next big thing... made of smaller things. [-]. |
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Make it out of Hubba-Bubba chewing gum, and you could have a Hubba-Bubba Hubble Bubble. |
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Nice idea oxygon, Sorry I have to rant on this. |
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Has anyone ever tried measuring the optical quality of a mylar bafoon using a zygo? I'm wondering if you could get..say..1/20th wave pv. Most likely not. Plus, how can you make it if you can't measure it? Freaking impossible, not even worth a thought. ....I don't undrestand : ) bang bang bang. Wow that hurts!
I can't imagine how difficult this would be. It's hard enough grinding a big mirror with so many known and measureable perameters here on earth let alone the vastness of a 5 billion AU freaking ballon. I just can't come up with all the data to back up my amazment at this wonderful idea. BONE |
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A couple thoughts - Helium should exist as a gas in the relatively high vacuum of space and at the relatively less high vacuum inside the envelope. At STP helium boils at ~4K. Also the tiny bit of heat from the electronics could warm the gas if something other than Helium were used. Secondly, radio waves seem more forgiving, use an appropriatly coated mylar bag as a radio telescope like Arecibo. One pickle I see is the mounting of the instruments. They could float weightless inside the sack and use small fans to "fly" into position. Cabling might distort the reflector or set up resonance that would disturb the alignment. Another idea might be to make the envelope spherical. As I recall at one-half the radius a significant part of the sphere inner surface would be very close to parabolic. Then you might use the envelope as both a receiving and transmitting "dish", if it could be apertured properly and the transmitter and reciever separately positionable. |
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