NASA is considering Boeing or SpaceX as the option to bring back Starliner astronauts.

• This week, NASA management has been debating whether to bring the agency's astronauts back on board the malfunctioning Boeing Starliner capsule or to send the spacecraft back empty.
• The Crew Dragon spacecraft from SpaceX is likely to be the replacement for bringing the crew back from the ISS.
• No decision has been made yet, and Boeing is still confident that Starliner can safely return the astronauts.
• Despite the agency's public confidence in Starliner, internal concerns suggest less confidence in the spacecraft.

This week, NASA officials have been debating whether to bring the agency's astronauts back to Earth using the malfunctioning Starliner capsule or to opt for a SpaceX rescue mission.

NASA's concern with Starliner, which carried astronauts Butch Wilmore and Suni Williams to the International Space Station in early June, stems from the failure of multiple thrusters during docking, a source close to the situation revealed to CNBC.

NASA is considering returning Starliner empty and using SpaceX's Crew Dragon spacecraft to bring back its astronauts. However, there is no agreement among those responsible for the decision, and the outcome of NASA's ongoing discussions is uncertain due to the many factors involved.

The "Calypso" Starliner capsule has been in space for 59 days and counting, serving as the final step to prove Boeing's long-delayed spacecraft is safe for crew missions to and from the ISS.

The Boeing crew flight, initially scheduled for a minimum of nine days, has been extended multiple times as the company and NASA conduct testing on the ground and in space to resolve the thruster issue.

Recent concerns indicate that NASA and Boeing leadership's characterization of the Starliner extensions as a data-gathering exercise may not accurately reflect the level of confidence within the agency regarding the safety of returning astronauts.

NASA has expressed mixed opinions about the status of Starliner, with SpaceX serving as a backup but Boeing's spacecraft being considered the "primary option" for return.

Boeing claims it has the "justification" to send astronauts back on Starliner, indicating the company believes the spacecraft can safely return without significant risk.

A Boeing spokesperson stated on Friday that the company remains confident in the Starliner spacecraft's ability to safely return with crew and is supporting NASA's requests for additional data, analysis, and data reviews to confirm the spacecraft's safe undocking and landing capabilities.

If Starliner fails to return with any cargo, the best option would be to retrieve the astronauts using SpaceX's Crew Dragon, allowing for the addition of Wilmore and Williams to the Crew-9 mission, which is scheduled to launch four people in the near future.

NASA did not respond to CNBC's request for comment on the ongoing Starliner discussions, but told Ars Technica that the agency is considering all options for the return.

NASA stated that no decisions have been made and the agency will keep updating on its planning.

Trusting the thrust

NASA reported that 27 out of 28 Starliner thrusters are functioning properly, aiding the spacecraft's movement in orbit.

The lack of a root cause for the failure of five thrusters during the flight to the ISS increases the risk of more thrusters malfunctioning during the return flight from an engineering perspective.

Despite "very significant" findings from thruster testing, Boeing's Mark Nappi, vice president of the Starliner program, has not yet identified the root cause during a press conference on July 25.

Nappi stated at the time, "We will continue to disassemble the hardware in order to definitively prove this."

NASA must now decide whether to trust that the issue with Starliner's thrusters will not recur and potentially lead to other problems.

An unpredictable outcome

The Commercial Crew Program Control Board met earlier this week to discuss Starliner's return, and NASA's lack of consensus arose due to the PCBs being a standard part of NASA's decision-making process, dating back to the Space Shuttle era, and being an effort to ensure any risks can be elevated to the highest levels of the agency's authority.

The PCB, led by Commercial Crew program manager Steve Stich, has not yet decided whether to proceed with a flight readiness review, which is the next significant step toward establishing a date for Starliner's return. The next PCB meeting is anticipated in the near future, and NASA has stated in a blog post on Thursday that return planning will continue into the following week.

If any members of the PCB disagree with the decision to return Starliner with a crew, the decision will be escalated to higher authorities until the dissent is resolved. Currently, the discussions within the PCB are unpredictable as NASA personnel debate the level of risk associated with returning crew on Starliner.

Making a choice

Astronaut safety is always the top priority for NASA when making decisions about human spaceflight, which is an inherently risky endeavor.

The decision NASA makes will have consequences that could impact Boeing's role in the Commercial Crew Program. Currently, Boeing's Starliner losses exceed $1.5 billion due to multiple setbacks and prolonged development timelines.

If NASA supports Boeing and reinstates Wilmore and Williams on Starliner, the agency will be taking on an unknown level of risk. A significant setback during the return, with the astronauts' safety in jeopardy, could force NASA to terminate Boeing's contract and withdraw from the program.

If NASA chooses to return Starliner without any payload, it could signal a lack of trust in Boeing, potentially prompting the company to abandon the project.

If NASA chooses the SpaceX alternative and Starliner returns safely, the agency may face criticism for overreacting to a perceived minor risk.