Monday, May 11, 2009

An Orbital Service Call to Hubble

Today, if all goes well, the Space Shuttle will take off with a cadre of astronauts whose main job will be to act as glorified technicians. There's nothing wrong with doing a technician's job well, and although I have said critical things about the Space Shuttle and NASA in the past, this trip is more justifiable than most. The Hubble space telescope, launched in 1990, has already outlived its nominal lifetime, and with some judicious repairs, scientists hope it will run for at least another five years or so. But as a recent National Public Radio report describes, fixing Hubble is no ordinary service call.

Take the 111 screws, for example. I have enough trouble in an ordinary 1-G lab keeping track of small screws involved in my research projects. If I spend a day or so building something, I'm pretty sure that at least a few minutes will pass with me on my hands and knees on the floor, looking for a critical nut or bolt that jumped off the edge of the workbench. Well, it turns out there's an instrument box on Hubble that needs to be accessed for repairs, but the designers never meant for it to be fooled with anywhere but on the ground. Hence the 111 screws, which would form a toxic cloud of malicious orbiting metal if just released around the telescope. Never fear, though. NASA engineers under the direction of Jill McGuire devised a plate with 111 or so tiny plastic boxes that fit exactly over the screws. A hole in each box is just big enough for the screwdriver to go through, but when the screw comes loose the only drifting it can do is inside the box. A snap-on replacement cover is part of the repair kit, so the astronaut doesn't have to find all those screws and put them back on.

This is engineering of an extreme kind, and I suppose that in testing the extremes of repair operations in the vacuum and weightlessness of space, NASA may come up with something that we ordinary Jills and Jacks could use as well. Back in the days when NASA was searching for reasons to justify itself after the end of the Apollo moon program, you heard a lot about "spinoff technologies"—ideas that were originally developed for the space program and turned out to be useful for earthbound applications as well. I have the unconfirmed impression that Velcro may be in this category, but other than that, I can't think of anything that's made a huge difference to the economy. I'd like to have one of those sleek little vacuum-and-zero-G-adapted hand drills they're using for my own toolbox, but not if I had to pay $180,000 or whatever the equivalent cost would be.

The Hubble, as with most astronomy, is pure science, and science is its own justification, culturally. To do certain kinds of science, you end up developing some weird engineering, such as plates that capture 111 screws in the vacuum of space. Offhand, I can't think of any other circumstance in which you'd need a screw-capturer like that, but maybe tools developed for some other obscure task the astronauts will do up there, will turn out to have beneficial consequences down here. Even if it doesn't, just getting the astronauts up there safely and back is something that takes a lot more resources than developing the hundred or so tools they'll carry with them. But that would get us into the manned-versus-unmanned space flight argument, and hey, I'm on vacation. I'd rather not argue. Let's just hope the repair trip goes well and Hubble gives us another half-decade or so of fine science. By which time, I also hope, we're well on the way to replacing the outmoded Shuttle with something better.

Sources: A written form of the report about NASA tools carried on NPR can be found at


  1. Scott Thourson9:00 AM, May 11, 2009

    In my opinion, that is the ideal type of engineering that I would like to do; problem solving and applying engineering creativity to such obscure and unconventional conditions. How would you like to step out of the normal life and engineer technology for totally different circumstances. That would be awesome! Very cool.

  2. I'm not sure if you're angle is sarcasm when you say "Let's just hope the repair trip goes well and Hubble gives us another half-decade or so of fine science," but in a way it seems like a very dangerous mission with some ethical considerations that must have been made. Personally, I wonder if it's worth upgrading Hubble, but if this mission goes well I'm sure the discoveries will be well worth the trouble. But does it make sense to replace Hubble with a new optical telescope outright? (James Webb Space Telescope will be going up in the next few years, but it operates in the infrared regime)

    I like the blog by the way. Keep it up.