Cosmonauts found a vital wrench misplaced in the Mir space station's 12-year-old accumulation of spare parts and were able to loosen a stubborn bolt that had forced them to cancel a space-walk, officials said on Thursday.

Yury Skursky, deputy head of technical analysis at Mission Control, said Russian engineer Nikolai Budarin and commander Talgat Musabayev used the wrong wrenches when they failed to open the station's hatch on Monday before an aborted spacewalk.He said they did not find the right tool beforehand, but officials said a search later in what cosmonauts describe as an often chaotic collection of odds and ends across the seven-module station found what they needed.

"They found the additional wrench and then went back just to test if they couldn't just loosen the bolt and the bolt was loosened, so if they needed to they could do a spacewalk," said NASA spokeswoman Kate Maliga.

Ten locks keep the final hatch closed, so the cosmonauts were able to loosen the troublesome bolt without opening the others.

The misplaced tool caused flight planners to delay two spacewalks planned for this week and reschedule the next repair spacewalks for next month, after a cargo resupply ship arrives with new tools later this month.

Also on Thursday, the Russian cosmonauts continued making repairs to the station's air conditioning system, which broke down in December.