Boeing’s Starliner was sitting on the Cape Canaveral launch pad in Florida when a small but critical problem with the spacecraft’s 200-foot (61-meter) booster rocket brought the countdown to a halt.
The American aerospace giant was hired by NASA to transport two astronauts – Sunita Williams and Barry “Butch” Wilmore – to the International Space Station (ISS) under a contract worth $4.2 billion (£3.3 billion).
But on May 6, engineers discovered that a valve used to control the rocket’s flow of oxidizer — which is mixed with fuel in a combustion chamber to create thrust — was causing an audible buzzing sound, forcing them to abort the mission .
This initial ‘sticky valve’ has been followed by a series of further problems. Still, NASA and Boeing went ahead with the launch on June 5.
With the defective Starliner and its passengers stranded in orbit for two weeks longer than planned, it’s a decision they may come to regret.
“The company is in a deep crisis. The optics of it are terrible,” said Rob Adlard, the CEO of British space launch company Gravitilab. “Space travel is super difficult, but it does contrast with the successes of SpaceX.”
The Starliner problems are another blow to Boeing, which has been dealing with a reputational crisis since a major safety failure on one of its 737 Max 9 passenger jets in January.
At 16,000 feet, about nine minutes into an Alaska Airlines flight departing from Portland, Oregon, pilots were forced to turn around and make an emergency landing after a door plug blew out, depressurizing the cabin and leaving a hole was left in the side of the cabin. airplanes.
In the aftermath of the incident, Boeing has faced strict scrutiny from regulators and calls from customers over its overall safety approach.
The apparently minor valve problem found on May 6, affecting Starliner’s Atlas V booster rocket (built in a joint venture between Boeing and Lockheed Martin), is typical of the minuscule problems that can wreak havoc on complex rocket launches.
On spacecraft, these valves control the flow of important gases such as helium, oxygen and other propellants. Boeing was previously forced to repair corroded valves in the Starliner found in 2021 after 13 failed on the launch pad.
Starliner, originally commissioned for a crewed mission in 2017, has been plagued by problems that have cost Boeing more than $1 billion, from software glitches to parachute issues.
The setbacks mean Boeing has fallen behind Elon Musk’s rocket company SpaceX, which also works with NASA to launch astronauts into space. SpaceX’s Dragon spacecraft has been conducting regular trips to the ISS since 2020.
After May’s discovery of Atlas V’s defective rocket valve, more problems followed. When engineers addressed the problem, they realized that Starliner was suffering from a helium leak.
The gas is used as a pressurizer to push propellant into the thrusters, meaning a leak could cause them to fail. Worryingly, the leak – which was traced to a poor seal – appeared to get worse during the tests, Steve Stitch, program manager for the NASA crew, said at the time.
Fixing the leak would require separating Starliner from the Atlas rocket, which would lead to longer delays, and NASA and Boeing decided it was still possible to proceed safely. Boeing’s Starliner manager Mark Nappi even said the delay had a “silver lining” because the company discovered the helium problem before the mission.
Starliner finally launched on June 5 at 10:52 am. But mid-flight, while the crew slept, more helium leaks were discovered and five of the spacecraft’s 28 thrusters failed as it approached the ISS. Wilmore and Sunita were forced to perform manual maneuvers in space in a docking procedure that took an hour longer than planned.
Another problem with the valves was also revealed, with one valve in the ‘reaction control system’, which helps steer the spacecraft, not closing properly. Starliner now relies on a backup “B valve” instead.
Now NASA and Boeing have the complicated task of double-checking Starliner’s systems and fixing as many problems in space as possible to ensure a safe return home.
At a press conference on June 18, Stitch said one thruster, the B1A3, fired at only 11% of expected power during a “hot fire” test, and will remain disabled for the remainder of the mission. He said the helium leaks and the thruster problems “appear to be related.”
Starliner was scheduled to return on June 14, but will now not be released until June 26.
On the ground at the Marshall Space Flight Center, experts are also testing copies of Starliner’s helium seals by “intentionally damaging a seal, cutting a seal and looking at leak rates” to assess the impact, Stitch said.
Boeing and NASA are confident the spacecraft can return, but they are being kept in orbit to conduct more tests to determine why the problems persist. Stitch said the team wanted to “make sure we were really ready to come home.” Boeing’s Nappi told reporters on Tuesday: “We have a good, safe spacecraft.”
Gravitilab’s Adlard said the issues sounded “solvable,” adding that some issues may have emerged because components “perform differently in the absence of gravity.”
Chris Welch, consultant and former professor of aerospace engineering at the International Space University in Strasbourg, said: “All these components are like links in a chain that all have to work in sync.
“Valves in particular are very small, clumsy things that have to work very precisely, over a wide temperature range and under challenging conditions.
“You can simulate them all you want, but you never know for sure how they will work until you actually put them in the field.”
If Starliner is further delayed, the ISS will have months of food supplies, while the spacecraft can remain docked for up to 45 days.
Although the helium gradually leaks from the craft, there is still enough for 70 hours of flight – and it only needs seven to get home.
In any case, NASA maintains that its astronauts have confidence in Boeing’s spacecraft, hoping that the next flight can take place in early 2025. Starliner.”
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