I have never seen a picture of a satellite being prepared for launch in anything but a cleanroom. Certainly, it is desirable that a high-precision optical system in a weather satellite (or spy satellite) does not arrive in space covered in dust, hair and lint, but why is a cleanroom necessary for GPS satellite (for instance), which uses only microwave transmitters that are highly insensitive to the type of debris a cleanroom filters out?
Is it simply a matter of space launches being so ridiculously expensive in the first place that the extra expense of the cleanroom is inconsequential? Or perhaps, does the use of a cleanroom actually provide some significant decrease in the risk of satellite failure, making it a worthwhile expense given the high cost of a space launch?
You answered your own question. It is so expensive to build a satellite and so expensive to launch it you want make the chance of failure as small as possible, and building something in a dust free environment eliminates many of the factors that can cause problems post launch… where it’s really expensive to fix something later.
It’s hardly just space stuff that gets made in clean rooms. All chips do, for a start, and loads of tricky medical things. A “clean room” is just a controlled environment to make or analyze stuff.
Big reason for the clean room is zero G. Anything, from a speck of lint to a soldier tin whisker, is a potential disaster waiting to happen once it’s in zero gravity.
Hubble aside, make that completely, absolutely, utterly, 100% **impossible **to fix later! Low Earth orbit might as well be the surface of Mars for a commercial satellite.
Related anecdote - my sister was involved in designing, building and launching a satellite a few years back, and she told me she deliberately wrapped a bit of her hair up in it so it would go into space. The satellite worked fine
I’ve built space-qualified apparatus. One problem is that, space being a vacuum and all, you have to guarantee that your nice clean-looking surfaces won’t outgas , say, oil all over the system lenses and cloud them up. Since even fingerprints* contain oils that are volatile, you want to avoid touching parts of the satellite with your hands ( hence the gloves and bunny suits) and you want to avoid being around things like vaxcuum pumps that are throwing lots of vacuum pump oil into the air. My system had surfaces “painted” with epoxy paint (since traditional paint “dries” by releasing volatile solvents), wires with non-volatile insulation, translation stages lubricated with non-outgassing lubricants, and all surfaces carefully cleaned and washed . Anything that couldn’t be verified as absolutely clean was baked in a vacuum oven until we were sure it wouldn’t give off anything.
It’s a true pain in the neck. You don’t realize how many things you use in everyday life can be a problem in vacuum until you have to account for all of them.
in a non-satellite-based incident,. I once heard a horror story from someone who had sealed up a cryopump-pumped vacuum system and couldn’t get his pressure down low enough. He was finally forced to disassemble the entuire system and search for the cause, at which point he founf the Fingerprint, made by one incautious touch by an ungloved hand.
Do they ever take precautions against bringing microorganisms into space? I heard contamination is very likely, and I thought it might mislead the search for life.
The only time that would be a factor is for scientific probes *looking *for extraterrestrial life, usually only surface landers. They represent a tiny percentage of launches. But yes, in those cases they have all the restrictions of launching a working payload *and *maintaining an uncontaminated scientific laboratory environment.
I think even GPS satellites have star trackers (optical sensors that use stars to determine the orientation of the satellite). And surfaces on such sensors can be easily contaminated by outgassing, as already explained above.
I’ve worked in a potato chip factory, and they actually are made in a clean room. Maybe not clean to the extent of a satellite assembly room, but cleaner than most rooms. It was washed with near-boiling water every few hours; employees wore plastic gloves, face masks, hair nets, beard nets, etc.
It was probably cleaner than the kitchen you prepared your meals in last night. (Certainly cleaner than my kitchen!)
