As to lifetime, we don't need a 30 year lifespan. If you average 6 years * 5 satellites you get 30 years and I suspect we could easily average 8-10 years.
As to thinking about this stuff. Clearly, but Hubble was specifically designed to make the Shuttle seem more relevant. Just about all of the major decisions where made for political not technical reasons.
Every decision at NASA is political - it's a government entity (look up Triana - that's another one I worked on. It's laughably ridiculous). But you're grossly oversimplifying. There isn't a prayer in heaven that would keep Hubble alive for 10 years on its own. Hubble made sense as a shuttle payload for a lot of reasons. I'm sure someone could have cooked up alternatives, but the one we got obviously did some good.
As government programs I think both Hubble and the Space shuttle where significantly better than average. Realistically redundancy is the first thing that gets cut at budget time etc etc.
Still, what makes you think building a Hubble equivalent that would last 8-10 years is outside the realm of the reasonable when Hubble is expected to last 7 or 8 years after the last servicing mission.
What you're saying isn't crazy. I guess I don't have a lot of faith in their estimates. NICMOS was supposed to last something like 4 years if I remember correctly. It died in about two. A whole slew of gyros failed, degrading performance, and jacking up schedules so we could replace them. COSTAR is a pretty obvious failure that wasn't fully recovered from (COSTAR took up one of four slots that were meant for instruments). Lots of stuff goes wrong. But maybe they could have designed a Hubble-class telescope that would last ten years back then. I don't know for sure. My gut says the first one would have been a piece of crap with a bad mirror and shitty gyros. That's a lot of work to throw away.
Either way, would launching three (or six or whatever) of those on rockets really have been cheaper than the Hubble in terms of science/dollar? I have some serious doubts. Throw in the politics and overhead of three major missions, and you're talking big numbers.
And that ignores the intrinsic value of manned missions for their own sake - you must do them to get good at them. There are people who say that we should never do a manned mission, and that all the data we want to collect can be had by unmanned satellites and whatnot. While it may be very close to true, that's a very short-sighted point of view in my opinion.
I get what you're saying, and I agree it's possible. But I think the position you're taking is too strong, in that you seemed to have accepted that it must be true. I think that what you're saying is reasonable, possible, and could be the case. But I don't think you have enough information to claim so strongly that it is certainly true.
That’s probably the most reasonable statement I have ever seen on the internet.
I try to judge past decisions in context not just based on what worked. At the time we did not know that each of those servicing missions would work or even if the initial launch would work. Though, clearly one path worked and the Servicing missions where incredibly valuable experience. But, they could have also cost a shuttle and several astronauts lives. Granted, the odds of multiple telescopes being sent up in a fairly short time period is tiny so it's only reasonable on a technical level.
In the end I think the Hubble program is completely justifiable, but that justification needs to be about more than just a quest for pretty false color pictures or worse an example of the sunk cost fallacy.
You bring up an interesting point regarding astronaut safety. It's interesting to me because I have the polar opposite opinion. This will sound cold, but astronauts are basically expendable. We can expect a small percentage of them to die. Much like in the military, the mission takes priority over safety, which comes second.
Given that we have no shortage of astronauts willing to accept that, and that we do put a ton of effort into their safety, I have no qualms whatsoever pushing the limits of what is possible. I've met a lot of astronauts - I don't recall meeting a single one who didn't fully understand how dangerous the work is. It's not for everyone. Personally, I think they're nuts to take that risk for what amounts to floating around in a stinky can for a few days, punctuated by brief stints of mechanic duty.
This always struck me as a major disconnect between the brass at NASA and the engineers. The higher up the chain you went, the more concerned with safety, politics, and perception they were, and the less concerned with what I would say the true goals of the space program are - the actual exploration of space.
Hubble was specifically designed to make the Shuttle seem more relevant.
It flows both ways. Hubble was designed to take advantage of the planned capabilities of the shuttle, but also, the Hubble was an important use case in setting shuttle requirements. And as I pointed out elsewhere in this thread, the shuttle dropped the ball on many of these, both functionally and in terms of delivery dates.
How do we get similar sized spy satellites into orbit without people? http://www.space.com/16000-spy-satellites-space-telescopes-n...
As to lifetime, we don't need a 30 year lifespan. If you average 6 years * 5 satellites you get 30 years and I suspect we could easily average 8-10 years.
As to thinking about this stuff. Clearly, but Hubble was specifically designed to make the Shuttle seem more relevant. Just about all of the major decisions where made for political not technical reasons.