ASSEMBLE a space MEGA-SCOPE at the space station!

[R1]

has assembling a mega telescope at the space station been seriously considered?<br /><br />for example a telescope (or a set of them) around 30 meters in diameter or larger , composed of many modules, assembled in space walks by the astronauts<br />wouldn't that be so cost effective and easier to accomplish soon? vs. a 100 meter diameter<br />scope on the non existent moon base?<br /> (each mirrormodule or spinning liquid tile or whatever has<br /> its independent fine tuning motor wired to the central computer) each tile module<br />is therefore replaceable and able to be fine tuned in live field operation<br /> <br />the same goes for any kind of large dish antenna...<br />you name it, infrared, radio wave, etc. it can all be put together by<br />the spacewalkers. <br /><br /><br />people already live up there,<br />they already do work outdoors,<br />isn't the next simple step to give them the kits to put together?<br /><br /> then we could even build say a few of<br />them and use them all synergistically a module the size of the shuttle payload could probably<br />be made to control it (or them) and even navigate them too...build 2 or 3 of them, each up to a miilion miles away from the other<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[mrmorris]

<font color="yellow">"...wouldn't that be so cost effective and easier to accomplish soon?..."</font><br /><br />No.<br /><br />A few reasons why this is unworkable (in no partular order).<br /><br />1. *Very* little work is done on each EVA mission. Working in Zero-G is very tiring, dangerous, and much harder than the equivalent job in gravity. A mirror of the type you envision would take literally thousands of man-hours to build <b>on-earth</b>. At the ISS -- it would take many thousands of spacewalks.<br /><br />2. Assembling a mirror for large telescopes is **extremely** precision work -- not something to be done while wearing boxing gloves.<br /><br />3. The ISS orbit bites for astonomy. It's only 400km up. While that may seem high to you -- it's very very low for space-based observations. Even the Hubble's 700km orbit is seen as been too low by many. It's only useful for astronmical observations about (from memory) 2/3 of the time. A telescope at the ISS orbit would be useful about (WAG) half that.<br /><br />4. That much mass on the ISS would make it impossible for the gyros and thrusters to maintain its orientation. <br /><br />5. The movements of the astronaut onboard the ISS would make vibrations that would completely destory delicate pointing of the mirror itself.<br /><br />6. Such a main mirror would act as a giant sunscreen -- seriously impacting the abaility of the solar panels of ISS to get enough light to maintain power.<br />

 

[R1]

thanks for the input, I'm sure most of those problems you mentioned are able to be worked out. <br /><br /> Your other option seems worse: build it on the non existent moon base and let the moon dictate where you aim it to and when.<br /><br />what are some possible solutions to each of your stated problems? maybe other readers<br />can help suggest <br /><br />evidently the scope wouldn't be used at the station itself, it should be navigated maybe 3000<br />miles further up upon completion. maybe even a million miles after its proven navigational reliabilty. <br /><br />during the spacewalks a tool attaches it to the infrastructure. These are smart tools, like little robots . each tile is able to be precision fine tuned during live field operation as needed. This is not like an average square- foot mirror that you glue or tape to walls, it's probably like a cubic-foot sized piece of equipment,<br />which includes the mechanism for independent calibration and communication, etc. <div class="Discussion_UserSignature"> </div>

 

[mrmorris]

<font color="yellow">"I'm sure most of those problems you mentioned are able to be worked out"</font><br /><br />Uh huh. Well, so long as you're having fun designing it -- more power to you.

 

[ve7rkt]

My suggestion would be that the telescope should have nothing to do with the ISS.<br /><br />If it's going to be robot assembled from pre-made self-contained mirror/navigation/data/calibration/communication modules, I say launch all your modules into the location where you want the telescope and have the robots assemble it there. Eliminating the astronauts solves problems 1, 2 and 5; separating the telescope from the ISS solves problems 3, 4 and 6.<br /><br />Building something like a large space telescope in one place and moving it to a final location afterwards (whether from 400km to 5000km, or from 400km to 1600000 km) sounds to me like a bad plan, because you'd have to make the structure rigid enough to be pushed like that. If you build it in one place and leave it there, it can be a lot weaker (lighter, cheaper).

 

[nacnud]

Depends on how you push it, ion drives are very low force.

 

[jmilsom]

One of the most exciting feasibility studies being funded by NASA at present is the "New Wrolds Imager" - a giant camera obscura or 'pinhole camera' in space. Theoretically it could image 'earth-like' planets up to 1,000 light years distant. There has been discussion of it on the Space Science and Astronomy Forum. Here is the thread:<br /><br />http://uplink.space.com/showflat.php?Cat=&Board=sciastro&Number=65281&page=0&view=collapsed&sb=5&o=0&fpart=all <div class="Discussion_UserSignature"> </div>

 

[R1]

does the pinhole telescope eliminate the need for a large (30 to 100meter diameter)<br />telescope in space?<br /><br />It sounds wonderful, this pinhole-telescope project, from Nasa's institute for advanced concepts.<br /><br />the reason for suggesting that we built it at the ISS is because we're already there doing<br />work outdoors. moving it shouldn't be a problem without solution. One of the shuttles payloads could be a navigation craft itself, which would slowly maneuver the giant scope <br />far away<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[nexium]

Generally it is wise to build a small pilot model first. 3 4/7 the Hubble altitude would still allow observing in some directions most of the time. The disk of Earth would fill slightly less than 1/2 of the sky. 4 small orientation errors of ISS likely cause little mischief. 5 A slack umbilical cord would greatly reduce the transfer of vibration and allow docking with the ISS during constuction and occassionly there after. 6 A smaller telescope would shade the solar panels moderaterately, perhaps rarely. Neil

 

[jmilsom]

I am sure we will continue over the years to put bigger and better telescopes in space. It really would not be practical or cost effective to do it at the ISS for the reasons outlined by MrMorris above. The ISS is too close to earth for a telescope. <br /><br />The most challenging aspect of the 'pinhole camera' project is launching and assembling the shade. This is a large object and needs to be very accurately placed - no way it could be done from the ISS. <div class="Discussion_UserSignature"> </div>