Astronauts 2: Robots 0

By Julianne Dalcanton | May 15, 2009 3:39 pm

Back when the current Hubble servicing mission was in jeopardy, there was talk that perhaps the repairs could be done robotically, without the expense or danger of a manned repair mission.

Well, on Day 2 of the repair spacewalks (EVA’s), I think we now know why sending a manned team might have been a good idea.

Let’s recap.

replacing the Hubble Space Telescope gyros

On the first EVA, one of the bolts holding in the old camera (WFPC2) in wouldn’t release. After running through every single contingency plan, Andrew Feustel eventually had to get out a non-torque limited wrench, and just plain guess how much torque to apply to the bolt, hoping all the while that it didn’t shear off. Maybe a robot could have handled that one, but I’d rather have a former Jaguar repair jock on the job (h/t commenter Peter).

On the second EVA, the situation was equally tricky. While the astronauts successfully extracted the gyroscopes, a pair of the new ones simply would not fit in. Luckily, they were able to grab some refurbished spares, that fit in just fine, but not after a couple of nerve-wracking hours digging deep into the contingency plans.

So, I’m two-for-two on being glad that actual humans were involved in these tasks. Given the trickery that’s going to be involved in tomorrow’s repair of the Advanced Camera for Surveys (think 100+ screws taken out by a guy wearing high-tech ski gloves), I’m guessing that tomorrow will be another hair-raiser.

  • mk

    “The cost of human spaceflight is so great that it would be far cheaper to send replacements than to make repairs.”

  • Jorge

    I’m having more fun following this repair mission than I do watching the olympics. Just saying.

  • Brian

    I’m really enjoying this. I read some of the perhaps more complete accounts, but your comments provide a personal perspective that I don’t get anywhere else. Thank you, Julianne.

    So far, so good. More drama than I expected for aspects of the mission that I was originally pretty optimistic about. Now come the repairs – I feel less confident about these. I hope that tomorrow we can celebrate a successful restoration of Advanced Camera for Surveys.

  • Mark M

    If humanity spent only a fraction of what it spends on killing each other on space exploration, we’d likely be on Mars already.

  • Brian

    “…(think 100+ screws taken out by a guy wearing high-tech ski gloves), I’m guessing that tomorrow will be another hair-raiser.”

    I’m hoping I can attach the state-mandated new license plate on my car OK.

  • federico

    You have a point there, a robot could flip off confronted with unexpected situations (I should find my old Asimov books).
    However, I still think that it would be nonsense to send poor human beings all the way to Mars (except for the drama). I would love to see a robot family instead.
    That would also make a great story. They could help each other as long as it gets, and then recycle their dead companions.

  • Julianne

    I do think that robotic repair missions would work just fine for a system that was designed from the beginning to be repaired by robots. But, HST ain’t such a system.

  • mk


    Exactly. That’s the problem.

    @Mark M…

    We are already on Mars.

  • Dave

    @julianne: I’m not sure I understand your point here. Robotic missions don’t take the people on the ground out of the loop, and they certainly don’t do our contingency planning for us. For the most part, the AI on these things is limited to fault protection, ie, keeping the robot itself from getting hurt.

    If an actuator hits a pre-programmed torque limit, it just stops actuating until a person tells it to do something else (in this case, that would be incrementally raising the torque limit until the bolt came free). So I think in all likelihood, the only difference between manned vs robotic here would have been that the robot could deliver the torque to the bolt with more precision and reduce the risk of accidentally shearing the head off the thing.

  • mk


    As I believe Julianne suggested–and forgive me if I misread– but if the telescope had been designed to allow for robotic repairs, the problems would be different. More robotic repair friendly if you will.

    And as I suggested by that quote above, if we didn’t design the Hubble to need maintenance by humans we wouldn’t be spending all that doe to repair it. We’d just replace it.

  • greg

    I for one am very happy that the Hubble Space Telescope was designed for in orbit servicing and repair by humans. The human race continues to reap the benefits from this decision. For this type of operation, the chances for mission success are so much more likely with humans in the loop. These Hubble servicing missions are the best use of the Space Shuttle by far.

    In orbit robotic repair? A lot easier said than done. A whole new infrastructure would have to be developed – and paid for – and tested. Maybe someday. I prefer the odds of success the way they are doing it now.

    I’m all for a vigorous and generously funded robotic planetary mission program (the planets are very far away) but for near earth space ops (low earth orbit, the moon, nearby asteroids, space station) the human in space makes a lot of sense.

  • Ellipsis

    I actually think the primary argument for human spaceflight (rather than, say, sending replacements every time something breaks) is the really really long term one, i.e. that (even though there are of course problems with making predictions this far into the future) somewhere in the range of 300 to 3000 years from now, I think it is unavoidable that overpopulation will be at such a point where the extreme challenges of forming a colony elsewhere actually are competitive with the difficulties of having no outlet for excess numbers of people on Earth. While people may occasionally whine about overpopulation now, this isn’t even remotely close to being this level of a problem, but eventually, looking at the extreme long range, it will be, and we will need to have things to such a point where we can get _large_ numbers of people off then.

  • Neal J. King


    It has often been noted that the birth rate declines in societies as people become more affluent. So a future alternative to your over-populated vision would be a richer but less populous Earth.

  • Ellipsis

    It’s true. I’m not sure which is more likely — I had always thought the overpopulated one, but looking at a list of birth rates by country now I’m not so sure. (I had thought that even in rich countries it averaged a little bit over 2, but looking at the list, the U.S. seems more the exception than the rule.) Ask a sociologist, I suppose!

  • Gavin Flower


    “While the astronauts successfully extracted the gyroscopes, a pair of the new ones simply would not fit in.”

    I am very surprised that the new ones had not been designed accurately enough to fit in the Hubble! Was it that that they could fit, but they wee too big to insert through the access hole?

  • gopher65

    Gavin: IIRC, 3 pairs of gyroscopes were replaced. 2 of the new sets fit just fine, but the 3rd one couldn’t be wedged into the hole. Instead they had to use a backup, one that had previously been extracted from Hubble 10 years ago, taken to the ground, refurbished, and now sent back up.

    I haven’t heard any official explanation yet, but my personal guess is that the slot that they fit into warped a little bit over time, and that the old gyros had warped with the slot, so they fit, but the new ones were straight as an arrow (like they should have been), so they didn’t fit. Just my guess.

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  • Derek

    Let’s remember that robots in low Earth orbit could be controlled directly by humans. We’re not talking about Mars rovers here. People seem to infer that a robot Hubble repair mission would be fired off and the robots would have to deal with every problem using some kind of sophisticated machine intelligence. They’re a few hundred miles up, for Pete’s sake! If medical technology is good enough to allow telesurgery across oceans, a well designed mechanical proxy could probably perform many repairs better than an astronaut. After all, it could provide a 360-degree view, ultra-high-resolution vision, a few extra hands, etc. Of course such robots have not been a big area of research for NASA, probably because they can lob up meatbags for $500M a pop. But I bet if they invested the cost of a shuttle launch or two in service robots, the results might be impressive. Look how far flying drones have come in only a few years? They are poised to replace airborne human pilots in many scenarios.


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