Two astronauts from the International Space Station (ISS) went outside the platform on Tuesday to carry out construction and maintenance work.
The six-hour-and-26-minute extravehicular activity was probably the last that will be conducted on the exterior of the ISS for many months.
The recent Columbia disaster means platform operations are being scaled back.
The current three-person crews are being reduced in size to two individuals. The first of these smaller expeditions will take up residence at the end of this month.
Commander Ken Bowersox and science officer Don Pettit used their spacewalk to reconfigure critical power cables, replace lighting for a transport trolley, and secure covers on the station's thermal control system.
They also collected up tools and tethers that had been left outside during previous spacewalks.
Cosmonaut Nikolai Budarin helped Bowersox and Pettit suit up and monitored the whole excursion from inside the Destiny Laboratory.
The first relief crew to be sent to the ISS since the loss of the shuttle Columbia is due to leave Earth on 26 April.
It will comprise Russian cosmonaut Yuri Malenchenko and US astronaut Ed Lu. Expedition Seven, as it will be known, will travel up on a Russian Soyuz TMA-2 spacecraft.
The Soyuz does not have the passenger or freight capacity of a shuttle, hence the need to downsize crews and suspend construction work.
The current crew, Expedition Six, has been on the orbital platform since November last year.
The three men would have returned to Earth in March had the shuttle disaster not occurred.
They will spend a brief period handing over before heading back to Earth in a Soyuz TMA-1 craft, currently attached to the ISS as a "lifeboat".