The Boeing Starliner has been refueled to begin its first test flight

A United Launch Alliance Atlas 5 rocket was refueled for a second launch attempt on Saturday for a boost Boeing Starliner crew capsule into orbit On the first test flight of the much-delayed crew capsule, a trip to the International Space Station.

With NASA astronauts Barry “Butch” Wilmore and Sunita Williams monitoring the ship’s robotic ascent, the Atlas 5 backbone was scheduled to launch from pad 41 at Cape Canaveral Space Force Station at 12:25 p.m. EDT, roughly the moment it loaded Earth rotation platform. To align with the space station’s orbit.

If all goes well, the Starliner will dock with the station on Sunday and arrive at the lab’s foreport around 1:50 p.m., and Wilmore and Williams plan to return to Earth on June 10.

The long-awaited flight will be the first test launch of an Atlas 5 rocket and the first for the Atlas family of rockets since astronaut Gordon Cooper lifted off just a few miles on the final flight of the Mercury program 61 years ago.

Likewise, this will be the first test flight of the Starliner, Boeing’s answer to SpaceX’s Crew Dragon, an already operational, less expensive spacecraft that has carried 50 astronauts, cosmonauts and civilians into orbit on 13 trips, 12 of which to the space station. Since an initial test flight in May 2020.

NASA funded the development of both spacecraft to ensure the agency could launch crews to the outpost even if one company’s ferry ship was grounded for any reason.

NASA had been falling behind schedule for years due to budget shortfalls and a variety of technical problems that cost Boeing more than $1 billion to correct, and NASA had hoped to send the Starliner into orbit on May 6. But the launch was canceled when United Launch Alliance engineers discovered a problem. With a pressure relief valve in the upper stage of the Centaur rocket.

The Atlas 5 was pulled from the platform and returned to ULA’s Vertical Integration Facility where the Centaur valve was quickly replaced. But following the launch, Boeing engineers saw signs of a small helium leak in the Starliner’s propulsion system.

The leak was traced to a plumbing flange that supplies pressurized helium to drive a specific jet to the Starliner service module’s reaction control system. The leak has been described as “very small”, but engineers need to prove it will not worsen significantly in flight and cause problems for other batches.

After extensive analysis and testing, mission managers concluded that the spacecraft could be safely launched as is, saying that even if the leak rate was 100 times worse than observed so far, it would not pose a risk to the crew or the mission.