Later today, NASA will attempt to autonomously undock Boeing's much-hyped Starliner spacecraft from the International Space Station and deorbit it for a soft landing in the New Mexico desert.
Serious technical problems with the spacecraft's propulsion systems led NASA to decide not to take the two astronauts it was carrying back home. Instead, NASA planned to have them return to Earth on a SpaceX mission in February.
But even without a crew on board, warns Don Nelson, a retired NASA Johnson Space Center engineer, there could still be risks.
"There is a high probability that the Boeing Starliner service module thrusters will exceed their design temperature limits and fail during deorbit," he wrote in an email to NASA's Commercial Crew Program leadership. "Therefore, there is also a high probability that debris from the service module and command module will land in a densely populated area...like downtown Houston?"
"The only safe way to handle the Starliner is to put it on a death dive deorbit trajectory in the Pacific Ocean," the email continued. "The NASA safety panel remains silent on this catastrophic issue. Will your silence cost someone their life?"
In an interview with Futurism Nelson warned that an imperfect deorbit burn for the troubled Starliner capsule could lead to disaster. A reentry at the wrong altitude could cause the capsule to break into pieces, which he said could crash over populated areas.
"If this thing isn't safe enough to bring the crew back, why is it safe enough to bring the vehicle back and risk it ending up in a populated area?" Nelson said. "That logic just doesn't make sense."
"Protect and save Boeing's money, but the people on the ground can go to hell," he added. "Let them duck and run."
Nelson was an aerospace engineer at NASA, working on missions ranging from Mercury and Gemini to Apollo and the International Space Station. He retired in 1999.
More recently, he has emerged as a critic of the space agency's safety practices - sometimes with ominous foresight. As detailed in his 2017 book "The NASA Letters," Nelson warned the White House in the early 2000s that there were too many crew assignments on NASA's Columbia space shuttle, noting that there was a "high probability of a system failure," as he told Futurism.
The shuttle Columbia crashed in February 2003 upon re-entry into the atmosphere, killing all seven astronauts on board.
"The vehicle just screamed that it had a lot of problems that needed to be solved," he added. "It was a really bad decision by NASA to put those people on that vehicle. We lost people that we shouldn't have lost."
Starliner's service module, which houses the failed thrusters, was always designed to burn up in Earth's atmosphere. However, the empty crew module is still scheduled to land in White Sands, New Mexico, delayed by a series of parachutes.
Earlier this summer, NASA engineers discovered that a Teflon seal in a valve, called a poppet, expanded while the Starliner's thrusters were firing, significantly degrading their performance.
NASA says it is playing it safe by performing a "breakout burn" maneuver to quickly get the spacecraft away from the ISS, in case it loses control and the space station is endangered.
However, Nelson fears that the combustion upon leaving orbit could still generate enough heat to swell the seals.
"And if that's the case, then you have a situation where, if that happens, you don't know where in the world the command module or the service module is going to go," he said. Futurism "What happens to them if we don't burn them all up is the question."
One alternative, Nelson said, is that Starliner could get stuck in orbit and continue to circle Earth for years before causing more potential problems down the road.
"If it stays in orbit, then you've got this thing up there flying around at low altitude, which will eventually de-orbit, and then break up again, and you don't know where it's going to go," he said. "That could happen a year from now, two years from now, even five years from now. It's a question of when they're going to come in if they don't complete this burn."
Nelson believes the Starliner would be better off not landing in New Mexico, but dumping it in one of the largest uninhabited areas on Earth: the Pacific Ocean.
"In the past, we've always planned our landings in the Pacific Ocean because the service module has components that are known to survive re-entry," he said. Flight controllers would have to "use short burn times" to slowly lower Starliner to the point where "atmospheric drag would bring it in."
"That would be my way of getting the damn thing down," he argued.
"The only reason to do this is to save Boeing money," Nelson added. "They could dump that thing in the Pacific Ocean and still have the ability to recover it."
Space debris falling on populated areas isn't a theoretical concern. Earlier this year, discarded batteries from the ISS crashed into a house in Florida, and SpaceX debris has landed in New South Wales, Australia, Saskatchewan, Canada and North Carolina in the past two years alone. In June, NASA and SpaceX announced they were investigating new ways to prevent similar incidents.
Nelson said the disastrous Starliner manned test flight was the result of a toxic "buddy-buddy" relationship between NASA and Boeing, and "incompetent" leadership.
Meanwhile, SpaceX's well-established Crew Dragon spacecraft is the "only viable option" NASA has right now, he argued. The spacecraft was developed under the same Commercial Crew program as Boeing's Starliner, but has completed just under a dozen crewed trips to the ISS without the same drama as Boeing's woeful Starliner.
In addition to Starliner, Boeing's other contributions to NASA have quickly become a multibillion-dollar headache for the agency. In a scathing report from NASA's inspector general last month, the watchdog found "a series of problems" with Boeing's Space Launch System (SLS). NASA hopes to use the massive rocket to send astronauts to the moon by the end of the decade.
The report cited "Boeing's inadequate quality management system, rising costs and schedules, and insufficient visibility into the expected costs of Block 1B."
"I think the people in Congress are finally going to realize that they're throwing money down a rat hole, and they're going to cancel it, hopefully before we kill the crew," Nelson said. Futurism referring to the sky-high cost of the SLS. "This thing is a monster disaster waiting to happen."
NASA did not respond to questions and Boeing issued the same statement it sent to media reporters about Starliner.
"Boeing remains focused, first and foremost, on the safety of the crew and the spacecraft," it said. "We are executing the mission as directed by NASA, and we are preparing the spacecraft for a safe and successful unmanned reentry."
NASA will attempt to undock Starliner from the space station tonight, and many in space at ground control will likely be keeping their fingers crossed.
More about Starliner: NASA admits there's 'tension in the room' after it said Boeing Starliner couldn't return astronauts to Earth
