Alan Stahler: Outward bound |

Alan Stahler: Outward bound

Silhouetted against Earth’s very thin layer of air, the Crew Dragon capsule approaches the International Space Station.
Photo Courtesy National Aeronautics and Space Administration

The Space-X Dragon capsule docked with the International Space Station last Sunday. Tomorrow, the Dragon capsule will return to Earth. Should it return its crash test dummy passenger in good shape, the vehicle will be well on its way to being “human-rated,” validated as sufficiently reliable to carry human crews into space.

Which raises the question, “Where in space should we go?”

Since the end of the Apollo moon program in the 1970s, there’s been only one place to go: LEO — low Earth orbit — circling Earth, round and round, a few hundred miles above the surface.

Should we head back to the moon? Head out to Mars?

Antarctica, straddling the south pole, is a forbidding place to live, especially during the south polar winter, when temperatures drop more than a hundred degrees below fahrenheit zero. Too cold to hold more than a trace of moisture, the air over Antarctica never rains, rarely snows. Despite its icy surface, Antarctica is a desert.

And for months out of the year, the sun never rises over the horizon, adding to the psychological challenge of staying alive — in both body and spirit — at the south pole.

And yet, compared to living in space, living in Antarctica is a walk in the park. A hundred-something degrees below zero is, after all, a lot warmer than the nearly absolute zero (-460) of space.

The International Space Station has been continually inhabited for over twenty years now. As expected, its six-person crew spends a third of its time on maintenance — fixing things that break, replacing fluids and filters, upgrading things that didn’t quite work right the first time.

Given our experience on the space station and in Antarctica, we have reason to believe humans can survive a prolonged adventure in space. But there remains one humongous unknown.

To stay alive, to stay healthy, to stay sane, we need food. We also need water, air, warmth, light and dark, quiet and stimulation.

All of these, should we launch toward the moon, or toward Mars, can be brought packed aboard the crew vehicle.

But something else to which we’ve become accustomed in our billions of years of evolution turns out to be as necessary as any of the above, but cannot be carried along: gravity.

Watching astronauts float around in the space station makes weightlessness look fun, and no doubt it is. But it takes a toll on the body. That muscles and bones fall apart is not so surprising. But so does the immune system, and many other, less-obviously gravity-dependent parts of the body.

Astronauts living on the moon on a months-long journey to Mars will need to take along some means of mimicking the effects of gravity, more than just the exercise equipment on which astronauts spend hours each day aboard the space station.

The traffic light turns green and you stomp on the accelerator, the horses beneath the hood press you back into your seat as if the seat-back were pulling on you, as if the seat had gravity.

If you could carry enough fuel to keep your rocket motor burning continually, pushing your space vehicle faster and faster — pushing you into your seat-back – you would, indeed, enjoy the feel of artificial gravity.

Take a hard right turn, and you’re pressed toward the door of the car, as if the door were pulling on you, as if the door had gravity.

Just changing direction — going around in circles, in a centrifuge — creates artificial gravity.

Problem is, unless such a facility were huge, every time you moved your head, your brains would realize you were spinning, reacting with a serious bout of space-sickness.

A small centrifuge, in which astronauts would ride some hours per day, looks likely to be standard equipment for future, long-duration space missions. To ensure the rider always faces forward — reassuring the brain that all is well — the machine would be well-stocked with videos.

Al Stahler enjoys sharing nature with friends and neighbors. He may be reached at

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