NASA astronaut Heide Stefanyshyn-Piper is lamenting the lost tool bag that escaped her grip during a Tuesday spacewalk outside the International Space Station. Stefanyshyn-Piper was mopping up a mess from leaky grease gun when the small bag came loose and drifted beyond her reach with its load of vital tools. "Well it was definitely not the high point of the [spacewalk]," Stefanyshyn-Piper said of the mistake during a series of televised interviews on Wednesday. "That was definitely disheartening to see that float away." Stefanyshyn-Piper was working outside the space station Tuesday with crewmate Steve Bowen on the first of four spacewalks to clean grit out of a damaged solar gear and add lubrication in a bid to restore its health. The gear is used to turn the space station's starboard solar arrays like a paddlewheel so they always face the sun. It was while preparing for that greasy job that Stefanyshyn-Piper, a veteran spacewalker leading the shuttle Endeavour crew's four excursions, opened her tool bag and found it full of sticky gray grease.