The world has been well-acquainted with the risks of space travel since the cabin of Apollo 1 went up in flames during a test launch, taking the lives of three astronauts. Though that rocket never left the ground, the deaths of Gus Grissom, Ed White, and Roger Chaffee were triggered by the biggest threat to humans in space: electricity. The cabin ignited when an electrical fire fed by a combustible nylon and high pressure oxygen gutted the un-fueled craft. Electricity and spaceships don’t mix well. And the problem only gets worse the farther from Cape Canaveral you go.
A major percentage of current spacecraft are unmanned, which is why we don’t hear about space fires more often — there’s no oxygen onboard. Propellant is generally flammable, but presents less of a risk. Electricity mostly represents a problem when you want to keep people alive, especially on longer trips — something we need to consider as we look towards Mars and even Alpha Centauri.
NASA’s already working on better understanding electrical fires in space in preparation for a future of increased space exploration and travels that will take us further than simply low-Earth orbit. The Saffire-1 experiment — in which the space agency will start a large-scale fire aboard an empty Cygnus resupply vehicle — is sure to help us better understand how a fire in a zero-gravity environment works, and what can be done to help protect astronauts who might be faced with such a situation. This is a start, but it assumes the electrical threat is from within. And it isn’t. Space itself could potentially start electrical fires.
J.R. Dennison, a materials physicist at Utah State University, has spent quite a bit of time digging into NASA’s concerns about how plasma-induced charging could cause spacecraft to experience a complete failure in electronic equipment and even lead to an explosion or two. Here’s the thing: We typically think of space as being an empty vacuum, but it isn’t. Space is thick with electron, ion, and photon-induced currents produced by stars and high-energy astrophysical events. These currents are unavoidable and, as spacecraft move through them, they can leave a charge on metal in much the same way wool does on a cold day. It’s dangerous enough to fly around in a small metal box, now assume the box is carrying a strong electrical charge. It’s a major problem that could stall human travel to deep space.
In essence, the problem that charging creates is that it gives engineers no room for error. If a faulty wire gets loose and happens to make contact with the exterior (or interior) of a charged-up vehicle, the astronauts are going to have a problem.
Dennison has been trying to figure out the more detailed dynamics by which spacecraft charging occurs. This includes where the charging is likely to occur on a spacecraft, the types of events that exacerbate charging (such as radiation or temperature rises caused by a solar flare), the types of materials that contribute or mitigate charging, and much more. Ultimately, the goal is to find materials with which we can build spacecraft that would not be conducive to charge buildup — i.e. non-static materials. This is much easier said than done. After all, you pretty much have to build spacecraft out of lightweight metals in order to achieve an acceptable level of safety in space. And they are conductive as hell.
Dennison hasn’t found the solution yet. He’s laid the groundwork out for what NASA and other space agencies and private spaceflight companies need to be aware of if they’re really serious about sending more people out into space. Meanwhile, there are no shortage of weird ideas that might help save the bucket of bolts and metal we continue to send up there.
One such proposal: water. A team of researchers from the Colorado School of Mines and the University of California, Davis think we could just go the old-fashioned way and use H2O to put out electrical fires in space. It’s better than nothing, though not exactly stunning as far as plans go.
Whatever fire-safety strategy NASA and others end up pursuing, they’ll need to figure something out soon if we want to hit that 2040 deadline for sending astronauts to Mars. The next great polymer won’t just be a materials science breakthrough, it’ll be a lifesaver.