How hard is it to design and make things that can go into space?

Question: How hard is it to design and make things that can go into space?
- Keywords:
  build,
  difficult,
  space
Asked by rhistevens77 to Ryan on 11 Jun 2019.
- Ryan Smith answered on 11 Jun 2019:
  
  It isn’t difficult to make something that can go to space, the difficulty is making it work when it gets there, and to work for a long time! Things like temperature, vibrations from the rocket, and radiation can all have a massive effect on the spacecraft, and it takes time to take all that into account.

Question: How hard is it to design and make things that can go into space?