Astronauts are performing spacewalks much more frequently as assembly of the International Space Station continues.
Initially performed only in emergencies, spacewalks are far more ambitious and frequent than NASA originally envisioned, USA Today reported. Although still risky, the spacewalks are required to complete the ISS.
NASA says it expects astronauts will perform more than 2 1/2 times the number of spacewalks during upcoming years than have been conducted since space flight started.
The construction of the space station has involved 47 spacewalks, with officials estimating 46 more will be needed. That compares with 78 space walks conducted between the first U.S. orbital flight in 1962 and the space station's opening in 1998.
Copyright 2006 by United Press International
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