The Boeing Starliner capsule, a cornerstone of Boeing's efforts to join the ranks of private companies ferrying astronauts to and from the International Space Station (ISS), has successfully returned to Earth. However, this journey was far from ordinary. The spacecraft, which was initially sent to the ISS with two NASA astronauts, returned alone, marking a unique chapter in its development saga. The empty cabin of the Starliner serves as a metaphor for the uncertainty and challenges that still lie ahead for this ambitious project. Hunter Woodhall Claims Paralympic Gold Month After Wife's Olympic Triumph
The Journey Back: An Empty Capsule
On Friday evening, the Boeing Starliner undocked from the ISS after nearly three months in orbit, beginning its return journey to Earth. This marked the end of a prolonged mission that was originally intended to last only about eight days. The Starliner capsule, affectionately named “Calypso” by astronaut Suni Williams, departed from its docking port just after 6 p.m. ET. The spacecraft spent approximately six hours free-flying through orbit, making its slow but steady descent toward its home planet.
During the undocking process, astronauts Butch Wilmore and Suni Williams, who had originally flown with the Starliner to the ISS, gave their well-wishes to the capsule from aboard the space station. Williams remarked to mission control, "It is time to bring Calypso home. You have got this. We have your backs, and you’ve got this. Bring her back to Earth." These words reflected both confidence and hope for the spacecraft's safe return, despite the unexpected turn of events that left the two astronauts behind on the ISS for an extended stay of five to six months.
Reentry: The Most Treacherous Leg of the Journey
As the capsule approached the most critical phase of its journey—reentry into Earth's atmosphere—close to midnight, tension was palpable among the ground control teams. Reentry is a complex and dangerous maneuver for any spacecraft, requiring precise alignment and timing. The Starliner had to orient itself correctly as it plummeted into the thick layers of Earth’s atmosphere at orbital speeds exceeding 17,000 miles per hour (27,400 kilometers per hour).
The immense pressure and friction generated during this phase could have heated the spacecraft's exterior to temperatures over 3,000 degrees Fahrenheit (1,649 degrees Celsius). Despite these intense conditions, the Starliner was able to withstand the heat, aided by a series of parachutes, which had been redesigned and rigorously tested by Boeing as recently as January. The parachutes slowed the capsule significantly before airbags were deployed to ensure a gentle touchdown at the White Sands Space Harbor in New Mexico, a site historically used for training NASA space shuttle pilots. At exactly 12:01 a.m. ET on Saturday, the capsule landed safely, bringing its nearly three-month-long mission to a successful conclusion.
A Groundbreaking Achievement with New Challenges
Mark Nappi, vice president and program manager of Boeing's Commercial Crew Program, praised the Starliner team for their meticulous work, which ensured a safe and successful undocking, deorbit, reentry, and landing. However, the mission's conclusion raises several questions about the future of the Starliner program. According to Steve Stich, NASA's Commercial Crew Program manager, it is not yet clear what the next steps for the Starliner will be or when the spacecraft could return to flight. He added, "That will take a little time."
Despite the uncertainties, the mission's successful entry and landing represent a significant achievement. Stich highlighted that the capsule's flawless entry and deorbit burn were impressive, noting, "The entry itself was just, and the deorbit burn was spot on." However, he also acknowledged that had the on-ground modeling been perfect, NASA might have opted to bring Wilmore and Williams home on the Starliner. "If we’d had a model that would have predicted what we saw tonight perfectly, yeah, it looks like an easy decision to go say we could have had a crewed flight — but we didn’t have that," he said.
An Unexpected Twist: The Starliner's Troubles and NASA's Caution
While the safe return of the Starliner capsule marks a significant milestone, the decision to fly the vehicle home without its crew was not made lightly. Initially, NASA officials were optimistic that they could resolve the Starliner's issues and plan a safe return with the astronauts on board. However, two major problems ultimately thwarted those plans: helium leaks and malfunctioning reaction control system (RCS) thrusters.
The helium leaks, which occurred during Starliner’s outbound flight in early June, raised concerns about the vehicle's ability to maintain precise orientation while reentering Earth’s atmosphere. Helium is used to pressurize some of the vehicle’s thrusters, which are essential for keeping the spacecraft oriented in space. The leakage issues were significant enough to delay the crewed test mission before launch.
Complicating matters further, five out of the Starliner's 28 RCS thrusters abruptly stopped working en route to the ISS. Although four of the malfunctioning thrusters were eventually recovered, one remained inoperable for the entire mission. These issues prompted NASA and Boeing to keep the Starliner in space for weeks longer than planned, extending the astronauts’ stay on the ISS from the expected eight days to several months.
The Complex Diagnosis: Understanding the Starliner’s Issues
NASA and Boeing worked tirelessly to identify the root causes of the Starliner's problems. They speculated that the "doghouses," structures containing propulsion equipment, were operating at higher temperatures than anticipated. This overheating caused some Teflon seals within the thruster systems to bulge, restricting the flow of propellant and leading to the RCS thruster outages. Additionally, officials suggested that the helium leaks might have been caused by seals that had degraded after exposure to propellant vapor.
However, determining the exact cause of the spacecraft’s issues is not an exact science. Even if the Starliner team had a clear understanding of the problems, inspecting the propulsion system on the actual vehicle in space was impossible. The Starliner was attached to the space station, making a thorough examination of the issues infeasible.
Furthermore, the service module—the section of the spacecraft housing the malfunctioning RCS thrusters and experiencing helium leaks—was designed to be discarded during the return trip to Earth. As planned, the module was jettisoned and did not survive the reentry process. This left the Starliner team without the ability to physically inspect the damaged components, creating ambiguity around what exactly went wrong.
Assessing the Risks and Moving Forward
The uncertainty surrounding the service module’s components and the thruster malfunctions was a critical factor in NASA’s decision to fly the Starliner home without its crew. As Steve Stich explained, "The bottom line relative to bringing Starliner back is — there was just too much uncertainty in the prediction of the thrusters. It was just too much risk with the crew, and so we decided to pursue the uncrewed path forward."
Despite these setbacks, the Starliner capsule was not entirely defenseless during its return. In addition to the 28 RCS thrusters, the spacecraft was equipped with 20 “Orbital Maneuvering and Attitude Control” (OMAC) thrusters, each delivering about 17 times the thrust of an RCS thruster. These OMAC thrusters played a vital role in keeping the vehicle oriented during its descent through space.
Nevertheless, NASA officials remained vigilant about the potential risks. During a previous news conference, Stich described a worst-case scenario involving a combined failure of the helium leaks and the RCS thrusters. Fortunately, this scenario did not unfold, and the capsule made it back safely.
Diverging Risk Assessments: NASA and Boeing
The return of the Starliner capsule also highlighted differences in risk assessments between NASA and Boeing. While Boeing maintained confidence in the Starliner's ability to bring the crew back safely, NASA opted for a more cautious approach. Stich noted, "There was just a little disagreement (between NASA and Boeing) in terms of the level of risk. It just depends on how you evaluate the risk. … We did it a little differently with our crew than Boeing did."
Ken Bowersox, NASA’s associate administrator for the Space Operations Mission Directorate, added that Boeing deferred the final decision to NASA due to the agency’s broader view of all the risks involved. Although Boeing remained optimistic as late as August 2, stating its high confidence in the Starliner’s ability to return with the crew, the company ultimately complied with NASA’s decision to proceed with an uncrewed return.
The Broader Implications for Boeing's Starliner Program
The performance of the Starliner on its uncrewed trip home will have significant implications for Boeing’s future in the commercial space sector. The company has already invested over a billion dollars in correcting issues with the vehicle, facing years of delays, development setbacks, and flight errors. The question now is whether NASA will require Boeing to repeat this test flight or consider certifying the spacecraft for regular missions following the safe landing.
This is not the first time Boeing has had to redo a test mission. In 2019, the company attempted an uncrewed test flight, but software issues prevented the vehicle from reaching the correct orbit and docking with the ISS. This prompted NASA to mandate a repeat mission in 2022. The company cannot afford many more setbacks if it hopes to compete with other players in the commercial space race.
The Path Ahead for Boeing’s Starliner
The Starliner capsule’s return to Earth without astronauts marks both a success and a challenge for Boeing and NASA. On the one hand, the safe landing demonstrates that the vehicle is capable of a precise and controlled descent. On the other hand, the issues encountered during the mission highlight the complexities and risks associated with human spaceflight.
As Boeing and NASA continue to analyze data from the recent flight, the future of the Starliner program remains uncertain. Will Boeing be able to resolve the issues and prove the reliability of its spacecraft? Or will it have to go back to the drawing board? One thing is clear: the journey of the Boeing Starliner is far from over, and its final destination is yet to be determined.
