Why is NASA's Boeing Starliner stuck in space?

NASA's Boeing Starliner spacecraft, currently docked at the International Space Station (ISS), is facing a series of technical issues that have significantly delayed its return to Earth. This unexpected situation has extended the stay of NASA astronauts Butch Wilmore and Suni Williams, who were scheduled to return on June 26. The updated return date of the spacecraft has not yet been announced by NASA.

What happened?

Wilmore and Williams launched on June 5 aboard Starliner's first crewed mission, a demonstration intended to secure routine flight certification from NASA. However, the Starliner spacecraft has encountered multiple technical difficulties since docking at the ISS. The spacecraft was meant to return on June 14, but issues aboard pushed back the return date to June 26 - which again, has been pushed back by NASA.

As for what issues caused the return pushback, official information states that five out of Starliner's 28 manoeuvring thrusters failed, hindering its ability to perform necessary orbital manoeuvres. The spacecraft experienced five leaks of helium gas, which is essential for pressurising the thrusters. Additionally, a slow-moving propellant valve highlighted issues from past test flights.

Some of these issues were apparent during the docking, states a report by Reuters. Boeing managed to address the issue by rewriting the necessary software and adjusting procedures, reviving four of the thrusters to allow for successful docking at the ISS.

Issues with the delay

The delay has extended Wilmore and Williams' mission well beyond the planned one week, turning it into a minimum three-week stay aboard the ISS. NASA and Boeing, according to official statements, are using the additional time to conduct further assessments for future missions. 

According to Steve Stich, NASA's commercial crew program manager, "Starliner is performing well in orbit while docked to the space station," and the extra time will offer "valuable insight" into system upgrades. As per a CNN report, he had stated in a prior news conference that the Starline can spend up to 45 days docked at the ISS, if the requirement ever arises.

A report by Reuters adds that the spacecraft's successful certification would make it the second US vehicle capable of carrying astronauts to the ISS, alongside SpaceX's Crew Dragon, which has been NASA's primary ride since 2020. However, the issues with Starline so far have contributed to significant cost overruns, with Boeing spending $1.5 billion beyond its $4.5-billion NASA development contract, further adds the report.