In late 2019, Boeing appeared to have a good chance of surpassing SpaceX to become the first private American company to carry astronauts into orbit.
In these four and a half years, many mistakes have been made. Here’s a timeline of the setbacks behind Boeing SpaceX in giving American astronauts a ride to low-Earth orbit.
December 2019: ‘A high-visibility close call.’
December 20, 2019 saw Boeing on the homestretch.
A Starliner capsule — the same spacecraft that will carry NASA astronauts Butch Wilmore and Suni Williams to the space station on Saturday — was on the launch pad of an Atlas V rocket.
The test flight to the space station does not have astronauts, and its mission is to evaluate the spacecraft’s navigation, propulsion and docking systems. If the flight passes this last technical hurdle, the trip will be carried by astronauts in a matter of months.
The Atlas V rocket launched flawlessly and released the Starliner.
Then the task crashed immediately.
The spacecraft’s clock is set to the wrong time, making the Starliner think it is in the wrong place. The capsule fired its thrusters to get to where it thought it should be. At the same time, a communication breakdown thwarted efforts by air traffic controllers in cruise control to diagnose and correct the problem.
The Starliner spacecraft used up too much propellant, and the planned docking with the space station was aborted.
During the fix, Boeing engineers discovered another software bug that could have ejected the wrong thrusters during a maneuver leading to re-entry. NASA called the incident a “high-visibility close call” that could have destroyed the spacecraft if bugs weren’t patched from the ground during flight.
An investigation revealed several failures in Boeing’s procedures that should have caught the mistakes before launch. A thorough audit reviewed one million lines of software code.
NASA officials admitted they had more confidence in Boeing, who has decades of experience working at NASA.
Summer 2021: Itching on the launch pad.
NASA and the company decided that a second test was needed before a flight with astronauts. The spacecraft was sent to the launch pad in July, but a problem with the space station prompted a delay in early August. Prior to the August 4 launch attempt, mission managers discovered corroded propellant valves on Starliner that were not opening. The test flight was aborted and another long round of troubleshooting followed.
May 2022: Another release, more issues.
A second unmanned test was launched on 19 May 2022.
During a maneuver to put the Starliner into a stable orbit, two thrusters failed, but the spacecraft managed to compensate. It docked at the space station and successfully returned to Earth.
July 2023: Parachute and tape.
Before the test flight with astronauts, later scheduled for July 2023, two more problems emerged. The protective tape wrapped around the wiring insulation became flammable, and a key component in the parachute system was weaker than designed and the Starliner’s three parachutes broke if not deployed properly.
About a mile of tape was replaced, and the parachute design improved and strengthened, then retested.
May 2024: Not yet ready to fly.
“This is a test flight so we’re taking our time to get everything going properly, and we want it to go well,” Steve Stich, program manager for NASA’s Commercial Group program, said during a May 3 news conference.
Mark Nappi, Boeing’s program manager for the Starliner, said, “We are ready to conduct a test flight. And I’ve never felt more prepared for any mission I’ve ever participated in.
But the Starliner wasn’t ready yet.
The countdown on May 6 was proceeding smoothly until a valve unrelated to the Starliner in the Atlas V rocket’s second stage began to operate, vibrating audibly at 40 times per second.
The launch was aborted, and the rocket had to be removed from the launch pad to replace the valve. The work was completed in a few days.
But a difficult problem emerged.
As the propellants were ejected from the tanks of the Atlas V rocket, engineers discovered a small helium leak in the Starliner’s propulsion system.
Helium, an inert gas, is used to push the propellants to the thrusters, and if too much helium is lost, the thrusters may not work properly.
A leak was detected in a seal in a helium line leading to one of the 28 small thrusters known as reaction control system engines.
During a telephone news conference on May 24, Mr. “There’s a seal that holds that interface tight, just like you’d have on your plumbing at home, a pipe or anything like that,” Stich says.
Tests showed no leaks in the seals leading to the other 27 reaction control system engines, and engineers believed a single leak could be dealt with. There are no plans to replace the seal needed to pull the Starliner from the Atlas V rocket, and the flight could lead to even longer delays.
“If that leak rate was 100 times higher, we could handle this particular leak,” said Mr. Stich said.
The helium leak led NASA and Boeing to take a closer look at the Starliner’s propulsion system, which revealed a “design vulnerability.” Mr. Stich said. If a series of failures occurs, the spacecraft will not be able to safely bring the astronauts back to Earth.
One of the backup plans is to use eight of the smaller thrusters if there are problems with the large engines fired for maneuvering the spacecraft out of orbit. However, analysis shows that additional failure means only four of the smaller motivations.
Engineers devised another backup plan to bring the Starliner out of orbit with four thrusters. NASA and Boeing officials said that after weeks of studying the problem, they believe they can overcome the problems that may arise from the leak.
And on Saturday, finally, perhaps, Mr. Wilmore and Mrs. Williams will fly on the Starliner.
