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...-- oxygon, Dec 17 2001 NASA to boldly go http://www.newscien...s.jsp?id=ns99992955Recently announced NASA idea to put telescopes at the Lagrange points in Earth-moon orbit. [krelnik, Oct 04 2004] Sci-Astro thread https://groups.goog...astro/c/-JAw0Ei6bEoDiscussing ideas for space telescopes. Part way through, someone suggests the use of a mylar balloon. [mitxela, Feb 17 2022] Bend-Forming of Large Electrostatically Actuated Space Structures https://www.nasa.go...d_Space_Structures/ [xaviergisz, Jan 31 2023] Spelling police: debris, not debree; vacuum not vacume, because, not becuase, truly, not truley. What happens when a meteorite hits the balloon?-- TeaTotal, Dec 17 2001 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.-- pottedstu, Dec 17 2001 let me define what I mean...
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...
I probably should have included that...-- oxygon, Dec 17 2001 If it's in deep space, how is the solar power element going to work?-- snarfyguy, Dec 18 2001 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.-- bristolz, Dec 18 2001 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.-- Urania, Dec 18 2001 UB - If there is pressure for it to burst - there is pressure for it to work.
It works! IT WORKS!!-- neelandan, Dec 19 2001 I hear NASA have stopped talking to Deep Space One.-- lewisgirl, Dec 19 2001 [Rods Tiger] - That would be debrie-- dana_renay, Dec 19 2001 Oh, UB.
<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>-- neelandan, Dec 21 2001 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.
Is that big enough for you?-- Vernon, Jan 11 2002 Peek-a-boo, I see you, UB.-- neelandan, Oct 28 2002 Interesting idea, wrong approach, though.
Instead of the lens, use a giant mirror. All you'd need is a reflective coating. The curvature does the rest.
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?
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.-- rapid transit, May 10 2003 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.-- cloudface, Dec 03 2003 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. [-].-- notOriginal, Dec 03 2003 Make it out of Hubba-Bubba chewing gum, and you could have a Hubba-Bubba Hubble Bubble.-- RayfordSteele, Dec 03 2003 Nice idea oxygon, Sorry I have to rant on this.
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-- clafever, Jan 22 2004 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.-- BWard, Jun 21 2004 I had the idea of an inflatable parabolic reflector space telescope, did a search, and found this one.
I'm surprised about the amount of negativity the idea got.
I read that to resolve features on an exoplanet, we're going to need a telescope of 40km diameter. An inflatable parabolic reflector is about the only way I can imagine that this size could be achieved.
The tricky part is figuring out ways to keep the shape of the parabolic reflector perfect enough to act as a telescope.
The mylar sheet could be reinforced with fibres (at the back surface). The sheet could be folded together 'origami style'.
The reinforcement fibres could be made of a material that is flexible above a threshold temperature, but becomes rigid as it cools in space after being inflated.
The telescope could use adaptive optics to compensate for imperfections in the primary mirror.
A telescope of this size and fragility could probably not be easily reoriented. So it could be used to monitor a single exoplanet. It could have a large flywheel/gyroscope (perhaps ring shaped around the edge of the parabola) to keep it pointed in one direction.-- xaviergisz, Feb 15 2022 [xaviergisz] maybe use [pashute]'s Fluid Flywheel idea, but using gas in the inflated rim. The "mirror" can be on the outside surface, held mostly by the inflated rim, with some supports behind to maintain shape.-- neutrinos_shadow, Feb 15 2022 Park another telescope at another Lagrange point, and use the interferometry with the Webb.-- RayfordSteele, Feb 16 2022 [xaviergisz] It's a good idea, hampered by [oxygon]'s terrible presentation.
I can think of a few ways of correction for spherical aberration, beyond only silvering a small portion in the middle. You could vary the thickness of the material, so that the balance between elasticity and the inflating gas distorts the natural shape of the balloon.
Another option is to spin the entire balloon, and let the centripugal forces distort it into an oblate spheroid. This may in fact make the aberration worse, but it might provide some degree of focussing.
A third possibility would be to accelerate the whole thing in the direction of interest. A very long cable attached to the front, with a spaceship acting as a tug. It would have to accelerate at a constant rate until the shape stabilized, but the amount of acceleration would control how distorted the balloon became. Similarly, a constant distortion of this type could be achieved by placing a counterweight on the end of the cable, and rotating the whole assembly, but since it would no longer be facing a fixed direction in space, the utility of such a telescope would be questionable.
Further thoughts: Assuming balloon physics follows the physics of bubbles, a membrane stretched over a circular opening, subjected to a pressure differential, becomes a segment of a sphere. Instead of building a whole balloon, build a solid ring, and stretch two layers of mylar across, one silvered and one transparent. When you inflate the gap between the layers, both would bulge outwards and assume spherical curvature. By varying the gas pressure, you would be able to adjust the radius of curvature, and by keeping the radius large enough, you wouldn't need to worry about spherical aberration.-- mitxela, Feb 17 2022 //vary the thickness of the material, so that the balance between elasticity and the inflating gas// This I like. Should be able to get a parabola; I suspect it's probably a linear relationship between spring rate & radius (parabolas are pretty simple).-- neutrinos_shadow, Feb 17 2022 I think it is the James Webb telescope that is being referenced in one of the comments. It mentions the Lagrange point.-- neelandan, Feb 27 2022 random, halfbakery