I am no fan of NASA, because I have worked with them. But - HST was not designed to fail, it was designed like an earth observatory where new instruments could be installed at a later time. Most of those "maintenance" missions provided different/improved instruments as well as fixes/modernization (and some of the updates mitigated the performance issues caused by the incorrectly shaped primary mirror). 31 years in Low Earth Orbit is a long time. LEO is a tough environment. In a sense, HST has 15 "days" per 24 hours (over 170k cycles to date), where the HST day is a sun/hot to dark/cold cycle. A fair amount of radiation, and atomic oxygen attacking exposed polymers. It has been over 12 years since the last repair mission. Most LEO spacecraft last less than 10 years, and usually have degraded capabilities due to the environment. With the exception of software maintenance, the HST cannot have regular maintenance like almost all other complex machines.Art
I freely grant you the designers, builders of that thing in LEO were/are genius. My tiny quibble was with the number of 'repairs' upgrades it still needed back when NASA was still involved in space flight and had, every year, to go to Congress for the do to for the dollars to fund them all. I worked at SPAWAR for long enough and it was all about ensuring the funding for 'scientists' to maintain work on 'projects' that would take your 7th grader about 40 minutes to do.
Exactly, based on my first hand experiences. This is why I am not a fan of NASA (or much of the bloated bureaucracies that are Govt organizations). Art