Space shuttle Endeavour crew members completed their mission's first spacewalk Friday, though it was cut slightly short after a sensor in one of the astronauts' spacesuits malfunctioned.

Space shuttle Endeavour crew members completed their mission's first spacewalk Friday, though it was cut slightly short after a sensor in one of the astronauts' spacesuits malfunctioned.

Astronauts Drew Feustel and Greg Chamitoff worked outside the International Space Station this morning for six hours and 19 minutes, completing their tasks at 9:29am Eastern time.

The duo successfully installed antennas for the External Wireless Communication system, routed cables, set up the antenna, installed handrails, and connected power cables. While working, however, a carbon dioxide sensor in Chamitoff's spacesuit failed. There was no evidence that he was in any danger, but without the sensor, officials had no way of monitoring his carbon dioxide levels. As a result, today's spacewalk concluded about 10 minutes before schedule, so they pushed plans to remove a micrometeoroid debris shield to a later spacewalk.

This was the first of four spacewalks for Endeavour's STS-134 mission and the 245th spacewalk conducted by U.S. astronauts, NASA said. It was Feustel's fourth spacewalk, but Chamitoff's first.

Among the tasks completed today was the installation of an ammonia jumper cable that will connect portions of the station's cooling loops. This had to be completed before the second spacewalk, during which Feustel and astronaut Mike Fincke will top off the ammonia in one of those cooling loops, which has a slow ammonia leak.

The astronauts then moved to the Destiny laboratory to install antennas for the External Wireless Communication system, which took about two and a half hours.

While this was going on, Pilot Greg Johnson and Mission Specialist Roberto Vittori transferred equipment and supplies from Endeavour's middeck to the station.

Endeavour on Monday and on Wednesday. Yesterday, a two-ton Alpha Magnetic Spectrometer-2 (AMS), which will be used to measure cosmic rays to gain a better understanding of cosmic radiation; a challenge for long-duration spaceflight. It might also help uncover the mysteries involved in dark matter or missing antimatter, as well as how the universe began.