Nasa launch paves way for return of stranded astronauts from space station
Butch Wilmore and Suni Williams could return to Earth next week.

The replacements for Nasa’s two stuck astronauts have launched to the International Space Station, paving the way for the pair’s return after nine months.
Butch Wilmore and Suni Williams need SpaceX to get the relief team to the space station before they can check out. Arrival is set for late Saturday night.
Nasa wants an overlap between the two crews so Mr Wilmore and Ms Williams can fill in the newcomers on happenings aboard the orbiting lab.
That would put them on course for an undocking next week and a splashdown off the Florida coast, weather permitting.

Reaching orbit from Nasa’s Kennedy Space Centre, the newest crew includes Nasa’s Anne McClain and Nichole Ayers, both military pilots, and Japan’s Takuya Onishi and Russia’s Kirill Peskov, both former airline pilots.
They will spend the next six months at the space station, considered the normal stint.
“Spaceflight is tough but humans are tougher,” Ms McClain said minutes into the flight.
As test pilots for Boeing’s new Starliner capsule, Mr Wilmore and Ms Williams expected to be gone just a week or so when they launched from Cape Canaveral on June 5.
A series of helium leaks and thruster failures marred their trip to the space station, setting off months of investigation by Nasa and Boeing on how best to proceed.
Eventually ruling it unsafe, Nasa ordered Starliner to fly back empty last September and moved the astronauts to a SpaceX flight due back in February.
Their return was further delayed when SpaceX’s brand new capsule needed extensive battery repairs before launching their replacements.
To save a few weeks, SpaceX switched to a used capsule, moving up Mr Wilmore and Ms Williams’ homecoming to mid-March.
Retired Navy captains who have lived at the space station before, the pair have repeatedly stressed that they support the decisions made by their Nasa bosses since last summer.

A last-minute hydraulics issue delayed Wednesday’s initial launch attempt.
Concern arose over one of the two clamp arms on the Falcon rocket’s support structure that needs to tilt away right before liftoff. SpaceX later flushed out the arm’s hydraulics system, removing trapped air.
The duo’s extended stay has been hardest, they said, on their families — Mr Wilmore’s wife and two daughters, and Ms Williams’ husband and mother.
Besides reuniting with them, Mr Wilmore, a church elder, is looking forward to getting back to face-to-face ministering and Ms Williams cannot wait to walk her two Labrador retrievers.
“We appreciate all the love and support from everybody,” Ms Williams said in an interview earlier this week. “This mission has brought a little attention. There’s goods and bads to that. But I think the good part is more and more people have been interested in what we’re doing.”