Be glad when NASA gets going again, we pay a lot of tax money for space, we used to get back technology to license to AMERICAN companies, now they switched it to private companies and we don't benefit from breakthroughs like computers etc anymore, America for sale, going to the moon took us a huge leap forward, we can't get tripped up again.
Because it's pretty simple, don't have to mix an oxidizer, but since they are assembled we still have issues like the Challenger, a joint burnt through and worked like a blow torch on the liquid fuel cell.