"SL" == Stuart Levy writes:

SL A few years ago someone from JPL came to UIUC to speak on SIM
SL prospects. I didn't get to ask the question that bothered me
SL most: he seemed to be suggesting it'd be in Earth orbit, but
SL surely that'd cause time- and direction-varying heating of the
SL spacecraft (...). It seemed awfully hard to compensate for, given
SL how stable they'd need the platform to be.

SL I just now looked on the SIM web page, and see that it's to be in
SL an "Earth-trailing solar orbit". Does that mean it'd be placed at
SL a Lagrangian point 60 degrees behind the Earth? If so that'd make
SL good sense for keeping a stable environment.

No, an "Earth-trailing solar orbit" is a heliocentric orbit in which
the Earth-spacecraft increases gradually. As seen from the Earth, the
spacecraft will appear to fall behind us. SIRTF is expected to be in
such an orbit. There was some discussion of SIRTF's orbit here
recently, you might check Google. Alternately, see the SIRTF Web
site.

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