The Boeing Starliner was sitting on the Cape Canaveral launch pad in Florida when a small but major problem with the spacecraft’s 191ft launch vehicle halted the countdown.
The American aerospace giant was hired by NASA to carry two astronauts – Sunita Williams and Barry “Butch” Wilmore – to the International Space Station (ISS) under a $4.2bn (£3.3bn) contract.
But on May 6, engineers discovered that a valve used to regulate the rocket’s flow of oxidizer — which mixes with fuel in the combustion chamber to create thrust — was making an audible buzzing sound, forcing them to abort the mission.
This first “sticky valve” was followed by a cascade of other problems. Nevertheless, on June 5, NASA and Boeing pushed for the launch equally.
Now that the malfunctioning Starliner and its passengers have been stuck in orbit for two weeks longer than planned, it’s a decision they may regret.
“Society is in deep crisis. Its optics are terrible,” says Rob Adlard, chief executive of British space company Gravitilab. “Space is super hard, but it contrasts with SpaceX’s achievements.”
The Starliner problems are a fresh blow for Boeing, which has been dealing with a reputational crisis since January when a major safety failure occurred on one of its 737 Max 9 passenger jets.
At 16,000 feet, about nine minutes into the Alaska Airlines flight that took off from Portland, Ore., the pilots were forced to turn around and make an emergency landing after a door stopper broke — depressurizing the cabin and leaving a hole in the side. aircraft.
After the incident, Boeing faced heavy scrutiny from regulators and calls from customers to take an overall approach to safety.
The seemingly minor valve problem discovered on May 6 that affected the Starliner Atlas V booster rocket (built in a joint venture between Boeing and Lockheed Martin) is typical of the tiny problems that can wreak havoc on complex rocket launches.
On spacecraft, these valves control the flow of important gases such as helium, as well as oxygen and other propellants. Boeing was previously forced to repair corroded valves on the Starliner, which were found in 2021 after 13 failed on the launch pad.
Originally commissioned for a crewed mission in 2017, the Starliner has been plagued by problems that have cost Boeing more than $1 billion, from software glitches to problems with parachutes.
The setbacks mean Boeing is falling behind Elon Musk’s rocket company SpaceX, which also works with NASA to carry astronauts into space. SpaceX’s Dragon spacecraft has been making regular trips to the ISS since 2020.
More problems followed May’s discovery of the Atlas V’s faulty rocket valve. As engineers tackled the problem, they realized the Starliner was suffering from a helium leak.
The gas is used as a propellant to push the propellant into the nozzles, meaning that a leak can cause them to fail. Worryingly, during the resulting testing, the leak — which was caused by a poor seal — appeared to be worse, Steve Stitch, NASA’s crew program manager, said at the time.
Repairing the leak would have required separating the Starliner from the Atlas rocket, causing a longer delay, and NASA and Boeing decided it was safe to proceed. Boeing Starliner’s manager, Mark Nappi, even said the delay had a “silver lining” because the company discovered the helium problem before the mission.
The Starliner finally took off at 10:52 a.m. on June 5. But mid-flight, with its crew asleep, more helium leaks were detected and five of the probe’s 28 thrusters failed as it approached the ISS. Wilmore and Sunita were forced to perform manual maneuvers in space in a docking sequence that took an hour longer than planned.
Another valve problem was also revealed, with one valve in the “reaction control system” that helps steer the spacecraft when it failed to close properly. The Starliner now relies on a backup “B valve” instead.
Now, NASA and Boeing have the difficult task of double-checking the Starliner’s systems and fixing as many problems as possible in orbit to ensure a safe return home.
At a press conference on June 18, Stitch said that one thruster, B1A3, had only fired at 11 percent of its expected power during the “hot fire” test and would remain shut down for the remainder of the mission. He said the helium leaks and the nozzle problems “appear to be related.”
The Starliner was scheduled to return on June 14, but will now disconnect until June 26.
On the ground at Marshall Space Flight Center, experts are also testing replicas of the Starliner’s helium seals “by intentionally damaging the seals, cutting the seals open, watching the leak rate” to assess the impact, Stitch said.
Boeing and NASA are confident the craft can return, but are being kept in orbit to conduct further tests on why problems are still occurring. Stitch said the team wanted to “make sure we’re really ready to come home.” Boeing’s Nappi told reporters Tuesday, “We have a good, safe spacecraft.”
Gravitilab’s Adlard said the problems sounded “fixable”, adding that some problems may have occurred because the components “work differently in the absence of gravity”.
Chris Welch, a consultant and former professor of space engineering at the International Space University in Strasbourg, said: “All these components are like links in a chain that must all work in sync.
“Valves in particular are very small, fiddly things that have to work very precisely, over a wide range of temperatures and under demanding conditions.
“You can simulate them all you want, but you can never be sure how they will perform until you actually put them out in the field.”
Should the Starliner experience further delays, the ISS has months of food supplies, with the craft able to remain docked for up to 45 days.
Even though the craft has been gradually leaking helium, it still has enough for 70 hours of flight – and only seven to return home.
At least NASA insists its astronauts have confidence in Boeing and hopes its next flight can take place in early 2025. Starliner.”
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