Generally speaking, a fire aboard a spacecraft
is what we would call a bad thing. So why
is NASA setting a fire on purpose?
The reason comes down to safety. NASA is planning
a series of three experiments called the Spacecraft
Fire Experiments, or Saffire. The two purposes
of Saffire are to investigate microgravity’s
effects on a large fire and to see if NASA’s
approach to fire protection is effective.
In the mission overview, NASA points out that
most habitable structures undergo extensive,
full-scale fire-safety testing. The same isn’t
true for spacecraft. While astronauts have
used flames in experiments before, it was
always on a small scale. The biggest flames
in previous experiments measured no larger
than 10 centimeters
(about 4 inches) in length or width.
Saffire will change that. In the first of
the experiments, scheduled to launch on March
22, a chamber in a Cygnus cargo craft will
play the role of an orbital fire pit.
First, the Cygnus will dock with the International
Space Station to deliver materials for other
experiments. Then, it will detach from the
ISS and move off to a safe distance. A thin
panel of cotton and fiberglass that’s .4
meters wide and 1 meter long will serve as
fuel. A hot wire on one edge of the panel
will ignite the panel
once the experiment begins.
What will happen when the material catches
fire? We don’t really know. Microgravity
might limit how large a fire can get. Or it
may turn into a raging blaze that would pose
a serious threat to crew and equipment. The
sensors will measure the experiment’s flame
growth, intensity and chamber oxygen levels.
The Cygnus spacecraft will remain in orbit
for a week to make sure NASA can download
all the data from the experiment. Then, Cygnus
and Saffire-1 will be deorbited and break
up upon reentry to Earth’s atmosphere.
NASA has two more Saffire experiments planned
after this one. Saffire-3 will use the same
sort of material as Saffire-1, but Saffire-2
will have a range of materials used in spacesuits
and spacecraft to see exactly how flame-resistant
they really are in microgravity.
NASA hopes to use this information to design
better spacecraft and spacesuits for long-distance,
prolonged space flights. That’ll come in
handy
when we’re ready to head to Mars and beyond.
One thing you can count on whether you’re
on Earth or Mars is that you’ll learn all
about the most interesting stories in the
solar system at now.howstuffworks.com, so
make sure to stop by every day. Being a Martian
is no excuse.
