49but they would fit within the existing structure with just enough
space for a single astronaut at a time. Spinning relatively quickly,
these could generate artificial gravity for short bursts while
the astronaut exercises. The idea is that gravity could perhaps be
dosed in small amounts; just enough to prevent the body deteriorating
in space. David Green and his colleagues at King’s College London
have been working with MIT and the European Space Agency (ESA)
on another solution: the ‘gravity loading countermeasure skinsuit’.
This skinsuit looks a bit like a triathlete’s sleeveless wetsuit,
and incorporates a specific weave of elastic material that provides
a graded tension between the feet and shoulders. This elastic loading
on the body simulates 1g (Earth’s gravity) and is designed to help
prevent stretching of the astronaut’s spine and muscle and bone
wasting. The scientists are running tests on their skinsuit on Earth,
and it was recently worn on the ISS by Andreas Mogensen,
the first Danish astronaut.
What about developing drugs that could help make exercise
in zero-g more effective or stop muscle loss altogether by blocking
the degenerative process? Nathaniel Szewczyk, at the University
of Nottingham, has been involved in research along exactly these
lines. But, rather than experimenting on human test subjects,
he has been using microscopic worms.
Caenorhabditis elegans is a nematode worm, but it has two different
muscle types that are similar to the heart muscle and skeletal muscles
used for movement in humans. As C. elegans is such a simple animal,
we’ve already been able to work out exactly how it develops, and
we’ve also sequenced its whole genome. This means that C. elegans
is a perfect test case for helping scientists understand the effects of
microgravity on animal bodies, and they’ve now been flown on
a number of space missions as microscopic astronauts. Szewczyk
and his colleagues have found changes in the cellular production
of around 100 proteins during spaceflight, many of them involved
in muscle-building. “These experiments with C. elegans in Earth
orbit have enabled us to track how the expression of different proteins
responds to weightlessness, and so explore the genetic basis behind
deterioration of the body’s muscles,” he says. “In our current
ESA flight, we’re specifically testing a few drugs to see
if they can reduce muscle loss in worms.”
So the hope is that, in the future, astronauts will be able to pop
a pill to help protect their heart and muscles while in space.