More insight on 'campout'

International Space Station managers now think a software hiccup prompted the alarms that cut short two American astronauts' airlock "campout" Monday night. Bill McArthur and Jeff Williams stopped the sleepover in the depressurized airlock a few hours early. The purpose of such campouts is to help purge nitrogen from spacewalkers' bodies to prevent "the bends" that divers can experience and shorten preparation time for spacewalks.

"The airlock campout was a test," McArthur told the Associated Press earlier today. "We were never in any danger." Another campout test is possible, he said.

"The main objectives of the test were highly successful," spokesman Kyle Herring said during today's station commentary on NASA TV. Tested were the automatic oxygen and nitrogen control inside the airlock and the behavior of the mass constituent analyzer (which McArthur recently worked on after some troubleshooting and whose erratic behavior may be to blame for the alarms). Despite the shortened sleep, managers also were able to gather "a significant amount of data" on oxygen usage during the campout, Herring said.