Space Station Saved By a Toothbrush?

Hugh Pickens writes "Denise Chow reports that two spacewalking astronauts successfully replaced a vital power unit on the International Space Station today, defeating a stubborn bolt that prevented the astronauts from properly installing the power unit on the ISS's backbone-like truss with the help of some improvised tools made of spare parts and a toothbrush. Astronauts Sunita Williams and Akihiko Hoshide started by removing the power box, called a main bus switching unit (MBSU), from where it had been temporarily tied down with a tether, then spent several hours troubleshooting the unit and the two bolts that are designed to secure it in place on the space station's truss. After undoing the bolts, the spacewalkers examined them for possible damage, and used improvised cleaning tools and a pressurized can of nitrogen gas to clean out the metal shavings from the bolt receptacles. 'I see a lot of metal shavings coming out,' Hoshide said as he maneuvered a wire cleaner around one of the bolt holders. Williams and Hoshide then lubricated a spare bolt and manually threaded it into the place where the real bolt was eventually driven, in an effort to ensure that the receptacle was clear of any debris. Then the two applied grease to the sticky bolt as well as extra pressure and plain old jiggling until finally 4½ hours into the spacewalk, Hoshide reported: 'It is locked.' When Hoshide reported that the troublesome bolt was finally locked into place, the flight managers erupted in applause while astronaut Jack Fischer at Mission Control told the astronauts 'that is a little slice of awesome pie.'"

Re:This is why we need people in space

[timeOday]

True, but not everybody's success rate is the same. One good trick is to start by turning the screw backwards until you feel it click, then start tightening.

Re:This is why we need people in space

[EETech1]

It is very easy for some CNC machines to tell if it has a dull or broken drill bit, or tap. I don't think it would take that much to add that capability to many of today's robots.

We had servo controlled torque wrenches with process monitors on a robotic production line where I worked that could also tell you way more about how that bolt (torque and turn) tightened than most observant skilled wrench operators (yes there is a skill to feeling a bolt tighten) and almost anyone that does it for 8 hours straight. Every bolt, every time, perfectly tightened, or rejected!

The logic to determine the failure (bolt, threads, nut, washer, or part interference) was there, and normally spot on, I doubt the programming to rework the various parts would add much to the complexity of today's state of the art assembly (line worker replacement) robots.

Cheers! to our manual labor (job) eliminating robot overloards!

Re:This is why we need people in space

[gagol]

A multitask space robot builder would probably pack cleaning brushes and advanced 3D printer.

Re:This is why we need people in space

[Solandri]

The power unit is probably vital only because the ISS is manned, and having humans aboard means a higher power requirement. The thing about space is that the enormous launch costs (on the order of $5000 per kg [wikipedia.org] at the low end) means many things you take for granted on earth (like a toothbrush and toothpaste) add horrendously to your overall cost. Estimates are that it takes about 2 tons of life support equipment to keep one person alive in space. So sending a single person to space incurs an extra $10 million in cost (ignoring consumables like food, water, and oxygen). For a fraction of that, you can just build your unmanned system with redundant backups for everything, including "vital power units".

e.g. The cost of the manned mission to repair the Hubble Space Telescope cost almost as much as building and launching a replacement HST. If we'd had an unmanned launch vehicle other than the Shuttle capable of putting something Hubble's size into orbit, we could've put 3 HSTs into orbit for the cost of one Shuttle-launched HST and one repair mission. Remember the Solar Max repair mission [wikipedia.org]? Ever wonder why aside from Hubble, that was the only repair mission conducted by the Shuttle? Because it was literally cheaper to build and launch a replacement satellite than to send the shuttle up to repair one.

We're trying to run before we can walk. We should kill the manned space program for about 10 years, or at the very least drastically scale it back. Work on lowering launch vehicle costs. Once we get those costs down to about $1000-$2000/kg (Falcon comes close), then restart the manned program. The Shuttle and ISS wasted hundreds of billions of dollars just so we could brag "Look! We have people in space!" If that money had been spent instead on researching and developing cheaper launch vehicles, we could've potentially been putting a dozen people in space for the cost of putting a single person in space today.

Re:This is why we need people in space

[khallow]

Russia has a couple as well with its Soyuz. Parachute didn't deploy on one and decompression of the capsule for the other. Wikipedia says these were designated Soyuz 1 and Soyuz 11.