EX: Consider how much better the space shuttle would have worked without a cargo bay.
I suggest that the savings of using unmanned missions, not making a serviceable telescope, and saving 1 full trip would have paid for construction of 4 additional telescopes with minor design updates for instruments and or fix bugs but no changes to major systems. With the added advantage of not risking astronaut lives on a publicity stunt.
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.
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.
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.
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.
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.
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.
Hubble was built assuming shuttle launches would be cheap. It wasn't.
You can indeed adapt your designs for unmanned launches and get a good life span out of them, but there are significant tradeoffs to doing so that impact the mission.
Further, there is value in manned missions just because. How are we to gain experience operating in space without sending people there?
There's a question of cost though. Each repair job costs about $1 billion and has a ~1% chance of killing the crew. (When Hubble was designed, it was thought that the Shuttle would be cheaper and safer than it was.)
If we could build an launch a Hubble for $1 billion, then it's obviously cheaper to send up a new one than repair it each time. If it lasts for 10 years, then if the unit cost to launch were under $3 billion then it would still be cheaper to launch a new one than fix one in-place.
So how much did Hubble cost? Wikipedia says $2.5 billion to construct. http://www.nasa.gov/pdf/499224main_JWST-ICRP_Report-FINAL.pd... says "Again, to put this in context, HST, which was a much less complex mission [than Webb], had a total cost-to-launch of approximately $5 billion in current dollars. Hubble’s LCC was approximately double this because of servicing costs over 20 years." (Those are 2010 dollars.)
Hubble also had huge cost overruns. The KH-11 has an estimated unit cost, including launch, of US$2.26 to 3.16 billion in 2015 dollars, says http://en.wikipedia.org/wiki/KH-11_Kennan#Cost . We've built several of those, which I assume helps reduce the per-unit costs.
If we could get the Hubble-like unit cost, including launch, down to $2.5 million, and with a 10 year life time, then we could launch 4 for what we've spent on Hubble, and lower risk through redundancy. "No serviceability" = "cheaper design" = "can launch more" = "lower risk". Again, this is based on the experience since the 1970s that manned missions are expensive and risky.
Regarding just because - your original question was "How would you have gotten even one HST sized telescope into orbit without a manned mission?" That's all I'm addressing.
That said, I remain deeply skeptical of the idea of being able to do so cost effectively or in a way that allowed for iteration and development of the systems. That's a lot of eggs in one basket to make 4 duplicates - they'd all fail in the same ways (which Hubble did early and often) and they'd be space junk in a heartbeat. You'd also want different cameras, which would have different requirements, etc. Once the contractors got a hold of that, they'd wind up 4 separate projects costing a fortune, and you'd be right back where you started, except without the budget. Keep in mind how long it took to build the HST. A servicing mission turned around in about 3 years.
Part of the reason for the expense of HST comes from the delay after Challenger. Hitching it to the success of the Shuttle helped make it more expensive.
You are right though that it plays to the sunken cost fallacy. Hubble happened because the initial budget was low. Then it ballooned. Congress would likely not have budgeted $10 billion if they knew that was going to be the final cost of Hubble. It's even less likely they would have funded four space telescopes for that price.
Maybe not. Hubble ended up costing over $2.5bn https://en.wikipedia.org/wiki/Hubble_Space_Telescope by launch day while a Shuttle launch cost around $450m https://en.wikipedia.org/wiki/Space_Shuttle . Certainly there would have been economies of scale, but it doesn't seem assured you would have got another four Hubbles for ~$500m extra. Moreover I'm not sure whether the redundancy would have dealt with the lens problem, or whether the same error would just have been replicated in all five satellites.
Shuttle launch cost around $450m x 6 = 2,700 million. Hubble mass: 11,110 kg
http://en.wikipedia.org/wiki/Delta_II 6,000kg to LEO launch costs ~51 million.
So if we went with a modular design vs user serviceable we could get a Hubble equivalent in ~2 Delta II launces (6,000 x2 kg to LEO = 12,000 kg) for 102 million x 5 = 502 million.
2,700 million - 502 million = 2.2 billion to build 4 more copies of a similar design plus some extra design costs etc.
PS: There were plenty of other options including arrays of smaller telescopes. For a recent example the Delta IV heavy can launch more mass to LEO than the shuttle $375 million per launch so the shuttle tax was very real.
(OTOH, all this is just considering what the best option for Hubble was, taking the existence of the Shuttle as a given. Justifying the existence of the Shuttle partly in terms of the Hubble would be more difficult: that $450m-a-flight figure doesn't seem to include development costs...)
http://en.m.wikipedia.org/wiki/2012_National_Reconnaissance_...