CAPE CANAVERAL, FL — Spacewalking astronauts are completing repairs to a cosmic ray detector outside the International Space Station.
NASA's Andrew Morgan and Italy's Luca Parmitano ventured out Saturday on the fourth and final spacewalk to fix the Alpha Magnetic Spectrometer.
They've been working since November on the $2 billion spectrometer, which has been at the space station since 2011.
The astronauts installed new pumps last month to revive the spectrometer's crippled cooling system.
Parmitano quickly discovered a slight leak in the new plumbing Saturday, and tightened the fittings.
If everything goes well, the spectrometer could resume its hunt for antimatter and dark matter next week.