Fortunately, we learned a lot about that problem building military surveillance satellites. I really don’t know how much of the knowledge carried over to space telescope design, but I’d imagine at least some of it did. Servicing One aspect of the HST is often overlooked: its ability to be serviced in orbit. The design challenges for that had to be considerable. Designing for maintenance is difficult at the best of times. You have to be able to provide access to important parts while providing those parts with all the support and protection they need.