NASA astronauts Butch Wilmore and Suni Williams are facing potential stranding on the International Space Station (ISS) due to technical issues with the malfunctioning Boeing Starliner capsule. The return of the two astronauts has been delayed for the third time, raising concerns among experts about their safety.

Initially scheduled for a nine-day stay, the astronauts' departure has now been pushed back to an undetermined date. The extended stay is necessary to allow for a thorough review of the technical issues encountered by the Starliner during its journey to the ISS. These issues include thruster failures and leaking valves, as confirmed by Boeing.

Experts have suggested that NASA might have to launch a rescue mission to bring the astronauts back to Earth safely, and in this scenario, Elon Musk's SpaceX could potentially be tapped to carry out the mission. Katsuo Kurabayashi, a professor of aerospace engineering at New York University, explained that if serious hardware defects were found with the Starliner, a rescue mission would become a necessity.

The scheduled return of the astronauts was first pushed back to June 14, and later rescheduled to June 26. NASA is currently evaluating return dates after planned spacewalks on June 24 and July 2, with the aim of bringing the astronauts back no later than early July. The agency is following a meticulous process, considering factors such as small helium system leaks and thruster performance.

The Starliner capsule has encountered multiple issues, including five failures of its maneuvering thrusters, leaks of helium gas used for pressurization, and a slow-moving propellant valve. These problems delayed the docking process, but Boeing made necessary fixes and successfully proceeded with the docking.

Boeing has faced significant cost overruns in the development of the Starliner, exceeding its $4.5 billion NASA contract by $1.5 billion. Understanding the causes of the thruster failures, valve issues, and helium leaks is crucial before the spacecraft can begin its return journey. Although only one thruster remains nonfunctional in the current flight, four thruster problems were encountered during the Starliner's uncrewed return from space in 2022.

The recent leak during the June launch raised concerns among a NASA contractor, who recommended double-checking safety protocols to ensure the Starliner's reliability. Experts have also expressed concerns about potential manufacturing issues that may have contributed to the repeated problems faced by the Starliner.

In light of these issues, some experts believe that SpaceX may be better positioned to provide an additional launch in the near future to bring the stranded astronauts back home safely.

In addition to the Starliner's technical problems, Boeing faced another incident last month when one of its planes experienced a rare Dutch roll during a flight. This incident further highlights the importance of thorough investigations and safety protocols for Boeing's aerospace technologies.

The fate of the stranded NASA astronauts remains uncertain as NASA continues to evaluate the situation and potential options for their safe return.