I can think of two things.
The first is a bit morbid, but consider what happens if some country ever decides to weaponize space. Being able to have people up there who can use the weapons available to them and exercise their independent judgement even in the face of an earth-to-space communication failure is important. It's the same doctrine that's behind ballistic missile submarines equipped with nuclear warheads.
The second is less morbid-- the colonization of other planets. This is necessary to protect the human species from an extinction event. Maybe even one that resulted from the aforementioned submarines. Naturally in order to colonize other planets we need to study the effects of space on humans. In order to do that we need to send them into space.
All of that said, I also believe most of our current missions can be done much more cost effectively by changing them to unmanned missions. But you can't take your eye of the long game, which just like the rest of history, is manned and involves militarization and colonization.
Did you see the article "Unsug hero of the nuclear age" a couple of days ago (yesterday?) on HN. That would probably shake your confidence in human reliability when facing the choice to launch or not to launch a warhead. Please have a look.
> The second is less morbid-- the colonization of other planets.
We can send humans in space, but the technology part that is lacking is still there: we don't have the "know-how" to colonize other planets, and before sending people in space there's a lot of work to be done in that field.
And sending people into space is how we're getting that know-how.
No, not at all. There's a bunch of other things we need to develop BEFORE sending people in space. That's my point. Putting people in a rocket is easy, but having them live, on their own, on a different planet is something else altogether.
I would love to hear you explain how to perform, for example, research on the effects of long-term zero-gravity on humans using only machines.
Or to take another example: I suppose it would have been possible to develop robots to repair the Hubble, but the cost of developing said robots to a point at which they can perform without failure is going to be equal - if not greater - than the cost of actually sending someone up to do the repair work in the first place.
The second example is an extraordinary claim presented without evidence, since the cost of sending humans to space appears to dominate the costs of the space program.
I don't think a machine can be inspiring like this:
http://ubuntuone.com/5LLIgal8tHKtHpFuDc3ZYl
We send machines to pave the way for humans, to see if it's safe and what precautions should we take.
If you said that only to humans in LEO, then I'd agree. There is no reason for a manned space station right now or humans riding along the satellites they launch. Maybe someday one would be useful as a buffer between long haul traffic and a new generation of shuttlecraft ferrying people and cargo to and from LEO for other ships to carry to deeper space, but that day only exists in our dreams of today.
Perhaps someday machines will be able to perform comparably with humans across a range of general actions, but it certainly not the case today.
I'm out to say this oft-repeated sentiment is trivially incorrect.
While there are a range of activities which can be performed better by machines than humans, there is still a very wide range of actions that can't be performed better by machines. One would expect technologists to understand this better than anyone.
But the crucial thing here is that a given human is capable of a much wider range of actions than a given machine. True, this can be made up for to an extent by using a wide variety of machines. Though at some point the weight of said machines will outweigh the human and their required support systems. And even then, those machines will be limited to a small subset of actions that the human can take.
So what do humans have that machines don't? Versatility.
PS- If I wanted to score points, I'd say he said "absolutely nothing", which overstates his case and makes your response invalid.
But unless the repair is going to be conducted by an AI—highly unlikely in the foreseeable future—then this is moot, as there will be a human brain in the loop in either case.
I certainly can -- appeal to voters. If space programs didn't have to appeal to voters to get funded, we could do away with manned programs entirely, and good riddance. It's said that an equivalent unmanned program costs just 10% of a manned one.
-- former NASA engineer.
The reason the astronauts flip the switch to start them: "The experiments could not be made fully automatic because NASA policy requires that experiments on manned missions involve the crew." Politics, again.
Due to the versatility and adaptability of humans.