In this screen grab from a NASA livestream, the Boeing Starliner spacecraft can be seen pulling away from the International Space Station for its unmanned return to the surface of Earth on September 6, 2024.
| Photo Credit: AFP

After months of turmoil over its safety, Boeing’s new astronaut capsule departed the International Space Station on Friday (September 6, 2024) without its crew and headed back to Earth.

NASA’s two test pilots stayed behind at the space station — their home until next year — as the Starliner capsule undocked 260 miles (420 kilometres) over China, springs gently pushing it away from the orbiting laboratory. The return flight was expected to take six hours, with a nighttime touchdown in the New Mexico desert.

“She’s on her way home,” astronaut Suni Williams radioed after Starliner exited

Ms. Williams and Butch Wilmore should have flown Starliner back to Earth in June, a week after launching in it. But thruster failures and helium leaks marred their ride to the space station.

NASA ultimately decided it was too risky to return the duo on Starliner. So the fully automated capsule left with its empty seats and blue spacesuits along with some old station equipment. SpaceX will bring the duo back in late February, stretching their original eight-day mission to more than eight months.

Boeing’s first astronaut flight caps a journey filled with delays and setbacks. After the space shuttles retired more than a decade ago, NASA hired Boeing and SpaceX for orbital taxi service. Boeing ran into so many problems on its first test flight with no one aboard in 2019 that it had to repeat it. The 2022 do-over uncovered even more flaws and the repair bill topped $1 billion.

SpaceX’s crew ferry flight later this month will be its 10th for NASA since 2020. The Dragon capsule will launch on the half-year expedition with only two astronauts since two seats are reserved for Wilmore and Williams for the return leg.

As veteran astronauts and retired Navy captains, Mr. Wilmore and Ms. Williams anticipated hurdles on the test flight. They’ve kept busy in space, helping with repairs and experiments. The two are now full-time station crew members along with the seven others on board.

Even before the pair launched on June 5, Starliner’s propulsion system was leaking helium. The leak was small and thought to be isolated, but four more cropped up after liftoff. Then five thrusters failed. Although four of the thrusters were recovered, it gave NASA pause as to whether more malfunctions might hamper the capsule’s descent from orbit.

Boeing conducted numerous thruster tests in space and on the ground over the summer, and was convinced its spacecraft could safely bring Wilmore and Williams home. But NASA disagreed and opted for SpaceX.

A minute after separating from the space station, Starliner’s thrusters could be seen firing as the white, blue-trimmed capsule slowly backed away. NASA Mission Control called it a “perfect” departure.

Flight controllers planned more test firings of the capsule’s thrusters following undocking. Engineers suspect the more the thrusters are fired, the hotter they become, causing protective seals to swell and obstruct the flow of propellant. They won’t be able to examine any of the parts; the section holding the thrusters will be ditched just before reentry.

NASA’s commercial crew program manager Steve Stich said earlier this week that teams have been so focused on Starliner’s return that they’ve had no time to think about what’s next for Boeing. He said the space agency remains committed to having two competing U.S. companies transporting astronauts.

The decision to transfer the crew of Boeing’s Starliner to a SpaceX mission after the spacecraft malfunctioned is just the latest twist in a long saga that has undermined the credibility of the US aerospace giant. 

Here is a recap of the setbacks and delays on Starliner’s journey to fly a crew to the International Space Station — and how it was unable to bring them back again.

2014: Nasa awards contract

A decade ago NASA chose two companies, Boeing and SpaceX, to each develop a new spacecraft capable of transporting its astronauts to the International Space Station (ISS). 

The US space agency asked both to be ready for 2017, as it sought to end its dependence on the Russian spacecraft it had used to ferry astronauts to the ISS since the end of the space shuttle program in 2011.

Boeing was awarded a $4.2 billion contract, against SpaceX’s $2.6 billion. At the time, billionaire Elon Musk’s young company was widely seen as the underdog against Boeing’s aerospace might. 

2019: Failed unmanned flight

During the first unmanned flight in December 2019, the capsule failed to set itself on the right trajectory and returned to Earth prematurely after two days, without reaching the ISS. 

The problem was due to a clock that was eleven hours late, preventing the capsule from firing its thrusters at the scheduled time. 

NASA then realized that another software problem could have led to a catastrophic collision. 

The manufacturer was given a long list of recommendations and modifications to make.

2021: False hope

In August 2021, when the rocket was already on the launch pad for another attempt at flight, unexpected moisture caused a chemical reaction that blocked the opening of some of the capsule’s valves. 

The capsule returned to the factory for inspection over a period of several months.

The delay was in stark contrast to the progress being made by SpaceX, which had been successfully transporting astronauts to the ISS since 2020. 

2022: First (unmanned) success

In May 2022, Starliner finally completed its first unmanned test flight.

Despite a few glitches — including a propulsion system problem detected in flight, but with no adverse consequences — the capsule lifted off, reached the ISS where it remained docked for several days, and returned safely to Earth. 

2023: New worries, new delays

Starliner’s nascent momentum was arrested in 2023 when new problems emerged, delaying preparations for its first manned flight.

One concerned the design of the parachutes that would slow the capsule as it re-entered the atmosphere. It was modified and new tests carried out. 

The other was even more surprising: adhesive tape, used over several meters to wrap electrical cables inside the capsule, proved to be flammable and had to be removed. 

2024: First manned flight goes awry

The big day finally arrived on June 5, 2024: the capsule lifted off with two astronauts — Barry “Butch” Wilmore and Sunita “Suni” Williams — for the first time, a final test mission to prove it was safe before beginning regular operations to the ISS.

But leaks of helium, the gas used to create pressure in the propulsion system, were discovered in flight.

Several thrusters then failed before the capsule docked with the ISS, although all but one were eventually reignited. 

NASA feared the capsule would not be able to achieve the thrust necessary to return to Earth. 

As a result, the space agency took a radical decision: to transfer the two astronauts to a SpaceX mission and return Starliner empty.

Analysis of the flight will determine the path forward — and how long any new delays will last. 

Boeing has already gone $1.6 billion over budget on the program.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)