Boeing will try to launch its first crew on Starliner, again

CAPE CANAVERAL — Troubled aerospace giant Boeing will try once more to fly its first crew to the International Space Station (ISS) aboard a Starliner spaceship on Saturday, after the last attempt was scrubbed hours before lift-off.

NASA astronauts Butch Wilmore and Suni Williams are "go" for launch atop a United Launch Alliance rocket at 12:25pm (16:25 GMT) from the Cape Canaveral Space Force Station in Florida.

The pair, both former Navy test pilots with two spaceflights under their belts, exchanged thumbs-up signs and waves with their families as they emerged from the historic Neil A. Armstrong Operations and Checkout Building on Saturday morning.

Clad in bright blue suits, they boarded a van for the journey to the launch pad, where they watched highlights from "Top Gun: Maverick" to get pumped up for the mission ahead.

Weather was 90 per cent favourable for launch, with winds posing the only potential for concern.

NASA is looking to certify Boeing as a second commercial operator to ferry crews to the ISS — something Elon Musk's SpaceX has already been doing for the US space agency for four years.

Both companies received multibillion-dollar contracts in 2014 to develop their gumdrop-shaped, autonomously piloted crew capsules, following the end of the Space Shuttle program in 2011 that left the US temporarily reliant on Russian rockets for rides.

Boeing, with its 100-year history, was heavily favoured over its then-upstart competitor, but its program has faced years of delays and safety scares that mirror the myriad problems afflicting its commercial airline division.

Wilmore and Williams were strapped in and ready to blast off on May 6 when a faulty rocket valve forced ground teams to call off that launch.

Urine pump

Since then, a small helium leak located in one of the spacecraft's thrusters came to light — but rather than replace the seal, which would require taking Starliner apart in its factory, NASA and Boeing officials declared it's safe enough to fly as is.

Pre-launch tests conducted by ground teams on Saturday confirmed the leak had not deteriorated further.

Once in space, the astronauts will put Starliner through the wringer, including taking manual control of the spacecraft.

A successful flight would help Boeing dispel some of the reputational damage sustained by successive failures over the years — from a software bug that put the spaceship on a bad trajectory on its first uncrewed test, to the discovery that the cabin was filled with flammable electrical tape after the second.

It's also important for more immediate reasons: The Urine Processor Assembly on the ISS, which recycles water from astronauts' urine, suffered a failure this week and its pump needs to be replaced, Dana Weigel, NASA's ISS programme manager, told reporters.

This mission will thus be tasked with carrying spare equipment, which weighs around 70 kilogrammes. To make way for it, two astronauts' suitcases containing clothes and toiletries had to be pulled off, meaning they'll need to rely on backup supplies kept on the station.

Elite club

Starliner is poised to become just the sixth type of US-built spaceship to fly NASA astronauts, following the Mercury, Gemini and Apollo programmes in the 1960s-70s, the Space Shuttle from 1981-2011, and SpaceX's Crew Dragon from 2020.

The seventh spaceship should be NASA's Orion capsule, on the Artemis II mission aiming to orbit the Moon next year.

If all goes according to plan, the Starliner should dock with the ISS on Sunday and remain there eight days as the crew carry out tests, including simulating whether the ship can be used as a safe haven in the event there is a problem on the ISS.

It would then undock, reenter the atmosphere and carry out a parachute and airbag-assisted landing in the western United States on June 10.