Boeing said Starliner can safely withstand up to five helium leaks. Just found the fifth one

The Boeing CST-100 Starliner spacecraft arrived at the International Space Station on June 6. It is scheduled to begin maneuvers to return to Earth on the 18th, but a new helium leak – the fifth since its takeoff – has Boeing and NASA engineers taking stock of the situation.

Helium leak. When the May 6 launch of the first crewed Starliner mission was delayed by a faulty valve on an Atlas V rocket, Boeing and NASA had time to discover a small helium leak in the spacecraft’s rubber seal.

Engineers determined that the leak did not pose any risk to the mission and gave the go-ahead for the spacecraft’s launch, which finally happened on June 5, after astronauts Butch Wilmore and Suni Williams had been in quarantine for a month.

Three helium leaks. During the flight to the International Space Station, mission engineers discovered two more leaks. There are only three leaks in the two helium manifolds of the propulsion system.

One was relatively large and caused a pressure loss of 395 psi per minute. NASA decided to close the helium collectors before docking with the space station. Upon opening, five of the 28 reaction control system (RCS) motors failed. One of them, directed backwards, did not work again.

Five helium leaks. After a brief delay to resolve an engine problem, astronauts Wilmore and Williams arrived in blazing rays at the International Space Station. At ages 61 and 58, this will likely be his last mission for NASA.

As for Starliner, Boeing engineers continue to discover new helium leaks. They discovered a fourth leak of 7.5 pounds per square inch per minute as soon as the craft docked at the space station’s docking port. Later that day, they discovered an even smaller fifth leak, measuring 1.5 psi per minute, which was only announced on Monday.

NASA is analyzing the situation. Boeing said before Starliner’s takeoff that fewer than five leaks would not jeopardize the integrity of the spacecraft. With the fifth leak confirmed, NASA is studying “what effects, if any, these five small leaks in the helium manifolds will have on the remainder of the mission.”

The helium collectors will remain closed until the return flight, but on that day they will have to be opened so that Starliner can use its RCS engines for undocking and deorbit maneuvers.

Although two lives are at stake, neither NASA nor Boeing are concerned about the results: the new leaks are very small compared to previous ones, and Starliner still has enough helium to last 70 hours of flight. The ship will take only seven hours to return to Earth.

Image | NASA/Robert Markowitz

In Hatak | Boeing’s Starliner spacecraft carried astronauts safely to the space station after five of its engines failed