Sunita Williams on Her Return Home After a Month in Space

After spending an unexpected month aboard the International Space Station (ISS), two US astronauts, Butch Wilmore and Sunita Williams, have expressed optimism about their return journey despite the challenges faced by their Boeing Starliner spacecraft.

Wilmore and Williams embarked on their mission on June 5 aboard the new Starliner, which NASA aims to certify for future crew transport to the ISS. They docked at station the following day, anticipating a stay of about one week. Although, their return was delayed due to thruster issues and helium leaks discovered during the mission.

While an exact return date has not been set, NASA officials indicated that “late July” is the target.

During a live press call from the ISS, Wilmore was asked about his confidence in the Starliner team and the spacecraft. He responded, “We’re absolutely confident.” Williams added, “I have a real good feeling in my heart that the spacecraft will bring us home, no problem.”

Williams also shared that they are making the most of their extended stay aboard the ISS. They have been involved in various tasks, such as replacing a pump in a urine-to-drinking-water processing machine and conducting scientific experiments, including gene sequencing in microgravity. Additionally, they have tested Starliner as a “safe haven” vehicle in case of ISS emergencies and evaluated its life support systems with four crew members aboard.

Remaining Challenges
Before Wilmore and Williams can safely return, engineers need to conduct additional simulations on the ground to understand the root causes of the technical issues encountered by Starliner, particularly with its thrusters and helium seals. Adjustments to the descent plan may be necessary based on these findings.

The spacecraft had known helium leaks before launch, but additional leaks were discovered during the flight. Helium, while non-combustible, is essential for pressurizing the propulsion system. Some of Starliner’s thrusters, which are crucial for precise maneuvering, initially failed during the approach to the ISS, causing a delay in docking. The cause of the thruster malfunctions remains unclear, although engineers managed to restart all but one.

Boeing executive Mark Nappi suggested that the thruster issues might have been due to overheating from excessive use. Possible causes for the helium leaks include debris in the propulsion system or improperly sized seals installed by Boeing.

Despite these issues, NASA and Boeing maintain that Starliner is capable of returning in an emergency, as the problems have only affected certain orientation control thrusters, not the main thrusters required for the “deorbit burn” to bring the spacecraft back to Earth. However, questions remain about the condition of the malfunctioning thrusters and whether they have degraded, which could necessitate the use of other thrusters during descent.

NASA official Steve Stich stated that the preferred plan is to bring Wilmore and Williams back on Starliner, although a return on a SpaceX Crew Dragon remains a possibility. This would be a significant setback for Boeing, which has faced scrutiny over safety issues with its commercial jets in recent years.

In 2014, NASA awarded contracts to both SpaceX and Boeing to develop crewed spacecraft following the retirement of the Space Shuttle program. SpaceX successfully conducted a crewed test in 2020 and has since transported dozens of astronauts to the ISS.