"NASA launches dual satellite moon mission" "The $500-million pair of washing-machine-sized satellites will take almost four months to reach the moon." Why are satellites that expensive/costly?

Well, part of the cost would be the launch itself $25k/kg 1 (granted that’s dated) and the time it’s taken to get here (since 2006) 2. Both probably have a lot to do with it. Not to mention the people involved, their time, cost, etc.

Another cost, along with the “technology” you mentioned already but might not have considered, is the shielding and component testing necessary to maintain function in a space environment. Radiation tolerance , component stress testing, temperature tolerance, micro impact survivability, etc all have to be tested and retested and sometimes redesigned which of course all costs $$$.

I worked for a place called Advanced Power Technologies in Bend, Oregon in the wafer fab. We made custom computer chips. One of our contracts was making chips for the power supplies in the International Space Station.

We are talking 50K for a single wafer. It isn’t cheap to modify an entire factory to make a few random parts. On the plus side I helped make and touched something that is in space.

Also there is a lot of built in redundancy so that if one system fails it doesn’t stop the whole mission. That’s going to add to the price tag.

A LOT of checking and re-checking during design and during assembly, special clean-room conditions through the whole build process, along with one-of-a-kind parts and one-of-a-kind machinery to make those parts per @johnpowell and the high launch costs per @wonderingwhy.

Space is a very harsh environment to design for. There are huge extremes of temperature: +250°F to -300°F. The ultraviolet will fry most materials (remember that UV on Earth will ruin many things, and that’s UV leftover from passing through 60 miles of atmosphere). Radiation will fry most normal electronics in a few days. Even 0 G makes things difficult – how do you ensure fuel in the tank is actually at the outlet, esp. if some fuel has been used and the tank is partially empty?

Also, they have a fancy high frequency beacon setup to measure tiny shifts in position between the two spacecraft as they fly in formation. The frequency is kept constant despite the environmental challenges.

I knew I could count on Fluther’s members to come up with clear and informative answers.
Thank you, @RocketGuy , @dabbler , @Lightlyseared , @johnpowell and @wonderingwhy!
I learned a bunch!

@rebbel Just so you know, @RocketGuy designs satellites for a living. His avatar is a picture of a satellite he designed.

Wow, that is pretty awesome!
Thanks @Rarebear .

I forgot to mention launch loads – that would be >10g vibration loads in all directions. It would be mighty uncomfortable if people were riding on.