Boeing’s beleaguered Starliner spacecraft bid farewell to the International Space Station (ISS) on Friday, embarking on its return journey to Earth without the astronauts who had initially boarded the vessel. This decision, made by NASA, came after concerns arose regarding unexpected thruster malfunctions and helium leaks that occurred during the mission’s ascent.
The Starliner mission, launched in June after years of delays, was intended to be a roughly weeklong test flight serving as a final evaluation before its certification for transporting crew to and from the orbital laboratory. However, the unforeseen technical hiccups forced NASA to prioritize astronaut safety, ultimately opting to bring astronauts Butch Wilmore and Suni Williams back to Earth aboard a rival SpaceX Crew Dragon. Their return, however, is slated for February 2025.
Starliner autonomously undocked from the space station at 6:04 pm Eastern Time (2204 GMT) and is projected to land at White Sands Space Harbor in New Mexico around 0403 GMT. As the spacecraft detached, Williams, referencing its nickname, radioed to mission control, “It is time to bring Calypso home.” A successful and uneventful return flight is paramount for Boeing, not only for reputational reasons but also for its future prospects of attaining certification.
The century-old aerospace giant had meticulously conducted extensive ground testing to replicate the technical challenges encountered during the spacecraft’s initial ascent, developing plans to prevent future occurrences. With its reputation already facing scrutiny due to safety concerns associated with its passenger jets, Boeing had assured the public and private stakeholders of its ability to safely bring the astronauts back to Earth – a reassurance that NASA did not share.
“Boeing believed in the model that they had created that tried to predict the thruster degradation for the rest of the flight,” Steve Stich, program manager for NASA’s Commercial Crew Program, informed reporters this week. However, he added, “the NASA team, due to the uncertainty in the modelling, could not get comfortable with that,” highlighting the tension-filled discussions during the decision-making process.
Shortly after undocking, Starliner executed a powerful “breakout burn” to quickly distance itself from the station, a maneuver deemed necessary to prevent a potential collision. This action would have been unnecessary if the crew had remained aboard, as they could have manually controlled the ship if required.
While the expectation is for Starliner to successfully execute its parachute- and airbag-assisted landing in the desert – as it has during two prior uncrewed tests in 2019 and 2022 – ground teams will meticulously scrutinize all aspects of its performance, particularly its problematic thrusters, leading up to the critical “deorbit burn.” This burn, scheduled for 0217 GMT, will guide the spacecraft back through Earth’s atmosphere.
A decade ago, NASA awarded multibillion-dollar contracts to Boeing and SpaceX to develop spacecraft for transporting astronauts to and from the ISS, a decision made following the termination of the Space Shuttle program. This program had left the US space agency reliant on Russian rockets for astronaut transportation. While SpaceX, led by Elon Musk, was initially considered the underdog, it ultimately outpaced Boeing and has successfully flown dozens of astronauts since 2020.
The Starliner program, on the other hand, has been plagued by setbacks. During its first uncrewed test flight in 2019, a software defect caused the capsule to miss its rendezvous with the ISS. A second software bug, detected and rectified just in time, could have resulted in a catastrophic collision between the modules. In 2021, blocked valves during a launchpad preparation for a new flight forced another postponement.
Finally, in May 2022, the spacecraft achieved its maiden journey to the ISS during a non-crewed launch. However, additional challenges arose, including weak parachutes and flammable tape within the cabin that required removal, further delaying the crewed test. For the current mission, Wilmore and Williams were strapped into their seats and ready for flight twice before late “scrubs” – cancellations due to technical difficulties – forced them back to their quarters.
