(HOUSTON) -- Two crew members aboard space shuttle Endeavour on Friday took part in the first spacewalk of the shuttle's 16-day mission.
Astronauts Drew Feustel and Greg Chamitoff floated in space to perform some basic maintenance work on the International Space Station and retrieve some experiments stashed outside the orbiting outpost.
Friday's spacewalk is the fourth for Feustel and the first for Chamitoff. It's the first of four spacewalks Endeavour's six-man crew has planned during their time in space.
A day before, the astronauts installed a $2 billion alpha magnetic spectrometer on the ISS, which could prove or disprove the Big Bang Theory of how the universe was formed.
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