Challenges of Space Exploration: Gravity Assisted Functions


One of my first assignments as a NASA contractor at Johnson Space Center in Houston back in the late 80s was to participate in a vendor survey seeking sources of medical equipment used for life science experiments in Spacelab (mock-up used for training purposed pictured above). If an item was available commercially, it could save a tremendous amount of money versus developing one from scratch and essentially reinventing the wheel.

When I would talk to each sales representative, who was usually rather excited to be talking to someone from NASA, the first thing I would ask would be, “Will this particular item work upside down?”

The ensuing silence never failed to make me smile.  After a sufficiently dramatic pause, I would explain.

Anything used in space needed to function without any assistance from gravity. This could be something as simple as a reagent moving through a tube or some mechanical part that required a nudge from the 9.8 meters/second/second acceleration of gravity.

Since we’ve all grown up on Earth’s gravity field, it’s easy to take it for granted. In fact, I was amazed to encounter situations where aerospace engineers made the mistake of designing something that was gravity dependent! How ironic is that? That’s how pervasive it is, that even someone trained specifically to work in the space industry would forget that important little detail. Along similar lines, when the shuttle would arrive in orbit, any tools left in the cargo bay, or anywhere else, for that matter, would come floating out, sometimes presenting a serious hazard.

Take a look around and think about some of the things you do every day that depend on gravity. Would your food stay on your plate or your drink in the glass? Nope. Could you wash your clothes in your washing machine? Nope. Would water run out of the tap so you could brush your teeth? Not unless it was under pressure and then it probably wouldn’t go where expected. Floating around looks like a lot of fun, but many an astronaut has battled with space sickness as his or her stomach was quite literally upset with food refusing to settle.

While my heroine, Creena, is onboard the escape pod, she encounters similar issues since it didn’t have a gravity simulator. To quote from “Beyond the Hidden Sky:”

“Nonetheless, there were still a few things she’d never get used to. Like the sanicube. She’d never thought of going to the bathroom or taking a shower as gravity assisted functions before, but they were, with equally bizarre solutions.”

Think about going to the bathroom standing on your head. More than likely, you wouldn’t like the result. Needless to say, toilet facilities in space require innovation to avoid what could otherwise be an extremely unpleasant environment. You can’t pick up a toilet that will work in space at Home Depot, that’s for sure, and developing one was expensive. Even then, it wasn’t ideal. I talked to individuals who were tasked with cleaning up the space shuttle when it returned from a mission who described a rather disgusting mess. Not only would it look as if the astronauts had engaged in numerous food fights, it would smell similar to a port-a-potty as well. Yummy, right?


It was quite common when I would go to schools to talk about space exploration that someone would inevitably ask about the space toilet. It certainly didn’t look anything like a normal commode. It employed assistance from vacuum hoses for urination and a general vacuum for defecation. I had a tour of the toilet training facilities with some of my coworkers one time which, of course, we found somewhat amusing. Potty training for astronauts certainly seemed a bit odd, considering all the high-tech training they received.

The funniest part was that the toilet in the training facility actually had a video camera inside it! This had an important purpose, i.e., so trainees could see if they were correctly parked on the seat, which was required to maintain that vacuum effect noted earlier. Failing to do so would result in, well, the possible escape of something you wouldn’t exactly want to encounter floating around, eh?


It didn’t take long for someone to dub it the “butt cam” and we joked about the possibility of someone broadcasting the training session across NASA Select, the private TV network that spanned not only Johnson Space Center but every other NASA facility and accessible in every conference room, lobby and manager’s office. No doubt the “butt cam” was on a closed circuit, but this shows the type of humor we engineers found in the most unlikely places. Yes, it was definitely fun and interesting to work at NASA.

How many “gravity assisted functions” that we Earthlings take for granted can you think of?



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