In a recent blog, I talked about the surprising difficulty of landing heavy crewed payloads on Mars — in fact, its present impossibility, in lieu of new technologies. That's a very big challenge to future Mars exploration, although not at all insurmountable. But what about the dumb stuff? The little things we take for granted on Earth that are actually quite difficult in zero-gravity? No, I don't mean using the toilet, although that's up there on the list.
How about this: A doohickey deep in the bowels of your Mars ship that keeps your communications antenna aimed at Earth fries a transistor. Sure, you've got a backup, but what if the backup fails, too? Answer: big trouble.
On a long mission to Mars lasting many months, you simply cannot drag along multiple spares of every piece of critical equipment. Like pioneers crossing to California in wagons, you have to be able to fix stuff. But to date, this is not at all part of daily operations in space. At the International Space Station (ISS), they pull a spare off the rack and toss the broken doohickey into outer space.
I just read a fascinating paper by Richard Pettegrew and John Easton (National Center for Space Exploration Research, Cleveland) and Peter Struk (NASA Glen Research Center, Cleveland). It's called Repair of Electronics for Long-Duration Spaceflight.
The paper talks about NASA's Component Level Electronics-Repair (CLEAR) project. The NASA brains are collaborating with the Navy to develop a plan for testing and repairing equipment in the space environment, as well as guidelines for designing equipment repairable in space.
It comes down to little things, to the dumb stuff we take for granted. Like, for example, soldering wires and components without gravity. On Earth, you heat the connection point and let the solder melt onto it, creating a tight, conductive seal. Without gravity, solder may behave differently. So the scientists plan experiments aboard ISS to determine whether components replaced and soldered in zero-gravity will function reliably.
It's heartening to see such attention to detail in the planning of a future mission to Mars or beyond. In space exploration, it's the dumb stuff that gets you killed. NASA learned that after the Challenger disaster, when we discovered that O-ring seals between solid rocket booster segments don't work right when it's too cold on launch day.