On August 29th, NASA made a significant decision to bring its astronauts back to Earth aboard a SpaceX Crew Dragon spacecraft rather than Boeing’s Starliner. This follows a rocky start to Boeing’s first Crew Flight Test (CFT) spaceflight mission, which launched on June 5th with two NASA astronauts bound for the ISS on an 8-day mission. However, things haven’t gone as planned. Starliner will now return to Earth uncrewed on September 6th, marking a substantial commercial and reputational setback for Boeing. Should a catastrophic failure occur during reentry or landing, it could spell the end of Boeing’s Starliner program altogether.

Boeing has provided abundant assurance that Starliner is safe for a crewed return. After all, they have already returned Starliner from LEO to a safe, soft landing in New Mexico twice, once in 2019 and again in 2022. Why does NASA not feel assured?

There are four critical contributory factors. Perhaps the most visceral is NASA’s 2003 experience with the loss of a crew of seven during the ill-fated space shuttle Columbia’s return to Earth. If there are fatalities, it will be seen as NASA’s failure, not Boeing’s. Secondly, this NASA-Boeing commercial contract is a fixed-price one. Boeing, not NASA, will have to pick up the additional cost necessary to certify Starliner as operational. Thirdly, NASA has an alternative option, something that was not available in 2003: SpaceX. Why should NASA take the risk if it doesn’t have to? Lastly, with a comprehensive understanding of all the intricate and interconnected technical details, NASA knows more than we do and feels it has no other choice.

Multiple Failures

NASA and Boeing have acknowledged “multiple failures,” which is not unusual in a test flight. The previous Starliner flights (in 2019 and 2022) were not without failures. The two main problems with Starliner in this CFT have made it to the public domain: five helium leaks and thruster malfunctions. The helium leaks, known about before launch, were not deemed significant. Starliner arrived and docked successfully with the ISS on June 6th. Boeing engineers assessed the leak rates and concluded that the remaining helium could support 70 hours of free flight, but only seven were required. Starliner had sufficient margin for a safe return trip from the ISS. 

Helium pressures the 20 Reaction Control Systems (RCS) for fine attitude control and 28 more powerful Orbital Manoeuvring and Attitude Control (OMAC) thrusters. All 48 are located in 4 units (each with 5 RCS and 7 OMAC) known as doghouses on the Service Module. The thruster malfunctions, specifically understanding their root causes, are the primary concern. When the OMAC thrusters are activated, they generate much more heat than expected. In the confined space of the doghouses, that heat is absorbed by the Teflon seals in the RCS, causing the seals to bulge and potentially disintegrate. The resulting debris can block the oxidizer supply to the RCS, resulting in lower thrust. Boeing engineers have replicated some of these symptoms in their ground tests. The uncertainty associated with repeated bulging of the seals during reentry appears to have motivated NASA to throw in the towel with Starliner. Starliner will return uncrewed on September 6th, and NASA astronauts Barry Wilmore and Suni Williams will return with SpaceX in February 2025.

This is perhaps NASA’s most consequential decision. NASA wanted two independent routes for crewed flights to LEO from the outset. Since the Space Shuttle was retired, NASA has spent about $11 billion on its replacement—the Commercial Crew Development Contracts. The lion’s share is almost equally split (SpaceX $5.5 billion and Boeing $5.1 billion). This includes 6 Boeing missions to the ISS and 14 SpaceX crewed missions to the ISS. SpaceX has completed 13 crewed return missions to the ISS, and Boeing has yet to complete its first.

Corporate Decline?

Following NASA’s decision, SpaceX will exploit Boeing’s uncomfortable reputational and commercial predicament. NASA did not take it lightly, and it was probably not informed solely by the quality of Boeing’s work on Starliner but by a broader recognition of Boeing’s performance over decades.

The first stage of the mighty Saturn V, which powered eight crewed Apollo missions to the Moon, was developed by Boeing engineers. From the same decade, the 1960s, Boeing has been a byword for safe aviation. The Boeing 737 and the 747 Jumbo have impressive safety records, not just in the US but globally. Perhaps the 1997 merger between Boeing and McDonnell Douglas shifted the company culture from safety and quality to profit and dividends. Confidence in the integrity of Boeing’s engineering declined further, with two fatal crashes in 2018 and 2019 of its new 737 Max aircraft, resulting in the loss of 346 lives.

Boeing’s difficulties are not restricted to aviation or Starliner. In early August, NASA’s Office of Inspector General published a report on the status of the Space Launch System (SLS) Block 1B. Boeing is the prime contractor for the SLS Exploration Upper Stage (EUS), where the cost has grown from $962 million to over $2 billion. The report found that Boeing’s quality assurance program is not compliant with NASA’s Quality Management System standard AS9100. Between September 2021 and September 2023, Boeing received 71 Corrective Action Requests and is now facing the prospect of financial penalties for non-compliance with quality control standards.

Critical Reentry

Despite media reports, NASA’s astronauts are not stuck, stranded, or abandoned. As the mission designation, Crew Flight Test, indicates, this is a test flight. Barry Wilmore and Suni Williams are space shuttle veterans. They are in no immediate danger and probably welcome their extended stay in space. It is very rare for a spacecraft that took people to space to return empty. In March 2023, the Soyuz MS-22 spacecraft returned to Earth uncrewed following safety concerns with an external cooling radiator on its service module.

The Service Module does not survive reentry, so Boeing engineers will not be able to investigate it further after it has returned to Earth. Firing all 28 thrusters during the uncrewed return will be essential for Boeing to collect additional data to inform the necessary modifications. That step may also result in unpredictable and potentially catastrophic failure. That unlikely event could vindicate NASA’s decision and mark the demise of the Starliner program.

I think Boeing engineers will succeed in returning the CFT safely to Earth. On the current schedule, on September 6th, Starliner will undock from the ISS at 6:04 and land on the 7th at 12:03 EDT.  Space is hard for Boeing right now, but it will have moved on in a few years. These profound difficulties will be interesting footnotes in Boeing’s developmental history.