Boeing's Starliner spacecraft, part of NASA's Commercial Crew Program, is facing a moment of uncertainty as two veteran astronauts onboard have extended their stay at the International Space Station (ISS) for a second time. The spacecraft encountered several issues during its first leg of the journey, raising concerns about the remainder of the mission.

Spaceflight veterans Suni Williams and Butch Wilmore arrived at the ISS aboard the Starliner on June 6, with an initial projection of a week-long stay. However, problems such as helium leaks and sudden thruster malfunctions have prompted engineers to analyze the spacecraft's issues while it remains attached to the space station.

To gain a better understanding of the problems, Williams and Wilmore will return no earlier than June 26, extending their mission to at least 20 days. NASA officials believe there is no reason to doubt the Starliner's ability to bring the astronauts back safely, but they want to thoroughly assess the data before making any decisions.

Boeing is attempting to view the mission as a learning opportunity, despite the "unplanned" nature of the challenges faced. A delay in returning astronauts to Earth is not uncommon, and the Starliner can spend up to 45 days at the ISS if needed. However, this situation adds to a string of setbacks for the Boeing Starliner program, which has already been plagued by delays and cost overruns.

The decision to extend the mission is primarily driven by the need for additional analysis. The helium leaks and thruster issues occurred on a part of the spacecraft not intended to survive the journey back to Earth. Mission teams hope to gather as much information as possible and investigate what went wrong.

Returning to Earth from orbit is always a perilous part of any space mission. The Starliner will have to endure extreme temperatures as it enters Earth's atmosphere at over 22 times the speed of sound. Following this, a set of redesigned parachutes will slow the capsule down before it touches the ground, as opposed to the traditional ocean splashdown.

Boeing and SpaceX were both chosen by NASA in 2014 to develop spacecraft capable of transporting astronauts to the ISS. While Boeing was initially seen as the frontrunner, SpaceX's Crew Dragon has since proved successful, completing a crewed mission in 2020 without major issues. The astronauts on that mission also stayed longer than expected, but this was unrelated to any software or hardware problems.

In contrast, Boeing's Starliner program has faced significant challenges throughout its development. Delays, setbacks, and additional expenses have cost the company over $1 billion. Previous uncrewed test missions in 2019 and 2022 highlighted software and thruster problems, some of which may still persist.

As Boeing continues to troubleshoot these issues, the success of the Starliner's current test mission cannot be compared directly to SpaceX's Crew Dragon. SpaceX had the advantage of years of uncrewed cargo missions to the ISS with its Dragon capsule before launching Crew Dragon. Boeing, on the other hand, had to build its crew vehicle from scratch.

If the Starliner encounters further setbacks, it may have to rely on its rival, SpaceX, to bring the astronauts back home. The mission remains a crucial test for Boeing, as it aims to demonstrate its capabilities and rectify the challenges that have plagued the Starliner program.