While nothing to do with emulation, I came across this ftp server with all kinds of data from NASA probes.

nssdcftp.gsfc.nasa.gov

It’s got all kinds of readings, and even some programs to interpret the data.. (FORTRAN from what I saw). It’s got to be one of the better clearing houses of space probe data available… I suppose later on I’ll see what’s involved in running some of these programs.. But I wouldn’t hold your breath…!

Even for the less inclined, there is jpeg & tiff data!

For example here is a picture from the viking project on Mars:
ftp://nssdcftp.gsfc.nasa.gov/miscellaneous/planetary/viking/images/vom_sj05s070.jpg

Stunning to say the least.