ASTRONAUTS on the International Space Station could survive if it was struck
by a piece of space junk, provided the hole blown in the station鈥檚 shell was no
bigger than 10 centimetres across, claim NASA engineers. Confident that a crew
could survive the depressurisation and evacuate the stricken module鈥攕o
long as they don鈥檛 take a direct hit from the molten metal produced as the
projectile tears through the module鈥檚 skin鈥攔esearchers at the space agency
have developed a puncture repair kit that would allow the astronauts to patch
the hole during a space walk.
Steve Hall at NASA鈥檚 Marshall Space Flight Center in Huntsville, Alabama,
says their aim is to 鈥渟eal punctures up to 10 centimetres in diameter caused by
collisions with small meteoroids or space debris鈥�. Anything larger, he says, and
the crew would probably not have time to respond to the rapid
depressurisation.
NASA鈥檚 puncture patch comprises a clear, polycarbonate disc that an astronaut
bolts to the evacuated module鈥檚 skin. An epoxy resin is then squirted into the
disc using a gun that mixes resin and a hardener. When the disc is full, the
resin is allowed to harden for a week, leaving a strong plug that seals the hole
well enough for the module to be repressurised.
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Hall reckons the patch will give the crew six months鈥� grace before a
permanent repair has to be carried out. 鈥淧ermanent repair techniques are highly
dependent upon the specific pattern of damage sustained, and they are being
studied separately,鈥� he says. 鈥淭hey may resemble the type of repairs made on
aircraft fuselages.鈥�
Walter Flury, space debris protection manager at the European Space Agency in
Darmstadt, Germany, agrees that such an exterior repair mechanism is vital. 鈥淣ot
all walls are accessible from the inside, as there may be equipment racks in the
way,鈥� he says. ESA has calculated that, over a 10-year period, there is a 19 per
cent chance of an inhabited 鈥渄ebris-critical section鈥� of the space station being
hit by an object between 1 and 10 centimetres in diameter鈥攂ut collisions
with most small objects, Flury says, should be absorbed by the station鈥檚
multilayered skin. ESA, which plans to launch the Columbus laboratory section of
the space station in 2003, is also studying puncture repair techniques.
