The first relief crew to be sent up to the International Space Station (ISS) since the loss of the shuttle Columbia has been officially named.
It will comprise two veterans of space flight, Russian cosmonaut Yuri Malenchenko and US astronaut Ed Lu.
Malenchenko was pictured by Lu on their spacewalk in 2000
Because the shuttle fleet is currently grounded, the Expedition Seven crew will have to make its way to the ISS on a Russian Soyuz TMA-2 spacecraft, set for blast-off on 26 April.
It will take over from Expedition Six, which has been aboard the orbital platform since November last year and which would have returned to Earth in March had the shuttle disaster not occurred.
Expedition Six - Ken Bowersox, Nikolai Budarin and Don Pettit - will spend a brief period handing over before making its way back down to the planet in a Soyuz TMA-1 craft, currently attached to the ISS as a "lifeboat".
Malenchenko, a pilot and engineer, knows all about long-stay space flight. He commanded a four-month mission aboard the Mir platform in 1994.
He also participated in an Atlantis shuttle mission in 2000 which prepared the International Space Station for permanent crews.
Lu, a physicist and expert in solar flares, has been on two shuttle flights.
In 1997, he flew aboard Atlantis to Mir to exchange US residents on the Russian complex, and he was also on that Atlantis ISS preparation flight with Malenchenko in 2000.
The two men did a spacewalk together during which they hooked up exterior cables on the ISS.
Had the shuttle still been in operation, Malenchenko and Lu would have been joined by cosmonaut Alexander Kaleri to make up a three-man crew.
But Kaleri has had to stand down; a two-man crew will put less pressure on supplies.
Kaleri will now act as backup along with astronaut Michael Foale.
British-born Foale, another Mir veteran, is scheduled to be the Expedition Eight commander.
This crew is not expected to fly for six months.
When Bowersox and Pettit return from the ISS, they will become the first official US astronauts to land in a Russian craft (California millionaire Dennis Tito returned from the space station in a Soyuz two years ago).
Operation of the ISS is in something of a holding phase.
Although experiments can still be carried out on the platform, further construction work cannot continue until the remaining three shuttles are cleared to lift new components and modules.