Boeing is planning to attempt a second launch of its Starliner spacecraft around 9:25 a.m. PDT on Saturday. 

"From a station standpoint, from our crew, from our ground teams, we are ready to go fly this mission," said Dana Weigel, manager of NASA's space station program. 

The Atlas 5 is the rocket propelling the Starliner into orbit. It is expected to take about 12 minutes, and then 25 hours for the Starliner to reach the International Space Station.

It is expected to dock around 10:50 a.m. PDT on Sunday.

The NASA astronauts, Barry Wilmore and Sunita Williams, plan to return to Earth on June 10 and will land in a desert area of Arizona or New Mexico, depending on the weather.

"I've talked to them, and they have every confidence in our rocket, they have every confidence in our spacecraft, in our operations teams and in our management teams," said astronaut Mike Fincke.

Wilmore and Williams originally planned to launch on May 6, but it was cancelled after engineers found problems with a relief valve used to maintain pressure in an oxygen tank.

While replacing the valve, Boeing engineers also discovered a small helium leak in the plumbing of the Starliner's propulsion system.

After tests and analysis, mission managers determined the spacecraft could fly safely as is.