[FPSPACE] trouble-shooting ahead - the James Webb

David Portree dsfportree at hotmail.com
Sat Nov 15 14:42:16 EST 2014


A lot of astronomers don't want clumsy, sloppy astronauts anywhere near their big, pristine telescopes, nor do they want their telescopes deployed in LEO, where atomic oxygen and orbital debris might cause trouble. On the other hand, some on the fringes of the human spaceflight world note that servicing telescopes at libration points (or perhaps at a servicing outpost at EML2) could provide astronauts with a real reason to get beyond LEO at relatively low cost and at a relatively early date. 
Someone did a study a while back that I found interesting - it argued that astronauts were no good for small L point telescopes because they were cheap enough to replace, no good for big L point telescopes because they were too fragile, and just right for middle-sized L point telescopes. Of course, if one pares down the number of telescopes that might be serviced by humans in that way, then one can be forgiven for wondering whether an L point servicing capability is worth developing.

David S. F. Portree
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Date: Sat, 15 Nov 2014 13:21:52 +0200
From: kgottschalk at uwc.ac.za
To: fpspace at friends-partners.org
Subject: [FPSPACE] trouble-shooting ahead - the James Webb

   Noting how often a simple deployment of one panel or one leg can go phut on the ISS or Rosetta, I have always been concerned about the on-orbit deployment of the mirror segments of the James Webb telescope at L2.  If any mirror is out of alignment (or is it collumation?) by even say ten angstroms, two decades of taxpayers' donations ends in heartbreak.

   Would it not make better sense to unfurl everything fully in LEO, & only after confirmed, measured success gently boost it to its L2 destination? This gives a last chance for servicing. It might require merely an astronaut or robonaut to give one good push to make something click into place.

- Keith



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