Astronauts can’t get away from
exercise even in space: Working out
in zero gravity prevents bones from
leaching calcium and slows muscle
loss. But whenever a shuttle astronaut 5 jogs on the orbiter’s treadmill, the
rest of the ship starts to rock and roll
from the vibrations. All that bouncing
around doesn’t do much for delicate
science experiments on board. 10
To help, NASA recently tested
three stationary-bicycle systems, all
designed to reduce vibrations; astro-
nauts tested the bikes on STS-50 last
summer. One design, the Ergometer 15 Vibration Isolation System (EVIS),
used a system of motors to counterba-
lance the movements of biking astronaut.
A second vibration–killing design called for the astronauts, to ride a
stationary bike suspended in midair via a spider-web pattern of eight bungee 20 cords. “it was an interesting ride-pretty stable actually,” says Rick Connell,
an engineer for Krug Life Sciences, the NASA contractor that developed
the bikes. Connell rode the bike on a special airplane used to test experiments before they run in space.
deck.
25
Finally, the astronauts test-rode a stationary bike bolted to the shuttle’s
They each produced 10 times less vibration than the treadmill. In face, sensors couldn’t describe a difference between the vibrations produced by the bikes and by normal levels of shuttle activity.