International Space Station Commander Peggy Whitson and Flight Engineer Jack Fischer floated in space and into the record books after the two astronauts made the 200 spacewalk in support of the orbiting laboratory.
The NASA astronaut duo is embarking on a 6.5 hour EVA to replace an avionics box, install a shield on Pressurized Mating Adapter 3 and rig a new high-definition camera and pair of wireless antennas.
Whitson then installed a connector to route data to the Alpha Magnetic Spectrometer, which measures cosmic rays, 100 billion cosmic rays to date. She's also spent more time in space than any other American, 552 days over three missions and counting. It provides power, cooling and communications capability to the spacesuit before the astronauts exit the space station, according to Rob Navias, the NASA TV commentator for Friday's excursion.
Friday's mission was Whitson's ninth spacewalk.
During preparations earlier in the morning, a small amount of water leaked from the connection point between an umbilical hose and Fischer's suit.
Since that time, space fliers from around the world have ventured out on spacewalk after spacewalk to build it into the complex network of living space and experiments it is today, hosting research and experimentation 250 miles (400 km) above the Earth.
CAPE CANAVERAL, Fla. (AP) An equipment water leak shortened Friday's spacewalk by two US astronauts at the International Space Station. Find us on Facebook too! The adapter will host a new worldwide docking port for the arrival of commercial crew spacecraft.
Watch the spacewalk live from NASA's website here.
An issue with some gear inside the airlock ahead of the spacewalk forced mission managers to delay the start time and shorten the walk in space.
The first spacewalk at the ISS was done December 7, 1988 by astronauts Jerry Ross and Jim Newman.
"This is wonderful, to be able to do the 200th EVA [extra-vehicular activity] on board the space station", Whitson said as the spacewalk came to an end. The historic spacewalk was Fischer's first. "It's humbling to be a part of their legacy".