Bad device replaced despite shortened ISS spacewalk

Astronauts float outside in station’s 200th spacewalk in effort to exchange faulty electronics box.

CAPE CANAVERAL — An equipment water leak shortened Friday’s spacewalk by two U.S. astronauts at the International Space Station, but they still managed to replace a faulty electronics box.

Despite the initial trouble, it was a milestone moment as Peggy Whitson and Jack Fischer floated outside on the station’s 200th spacewalk.

The astronauts wasted no time removing the old electronics box, their No. 1 chore, and plugging in a new unit.

The device — a bit unwieldy at more than 5 feet long — supplies electricity and data to science experiments on the outside of the station. The pair also whipped through other tasks, leaving only two undone.

During earlier preparations, a small amount of water leaked from the connection point between an umbilical hose and Fischer’s suit. The hose is one of two that provide water, oxygen, power, cooling and communications for astronauts before they float outside.

The leaky hose had to be disconnected before the spacewalk could begin. The astronauts ended up sharing Whitson’s hose while they waited, which reduced their suit battery power. As a result, Mission Control cut the spacewalk from the intended 61⁄2 hours to four hours before it began.

The change-out went so well and fast 250 miles up that the spacewalkers had time to squeeze in a few other chores including the addition of a special data connector to the Alpha Magnetic Spectrometer.

Launched in 2011 on the next-to-last shuttle flight, the high-profile particle physics detector known as AMS is still working and has measured 100 billion particles.

But it’s in need of repairs because of failing coolant pumps; Friday’s work on a bypass route for data should help future efforts.

NASA Astronauts Peggy Whitson and Jack Fischer, shown, worked outside Friday on the station’s 200th spacewalk.