Tag: SpaceX

With no consensus on the safety of the Starliner crew capsule, NASA officials said Wednesday they need another week or two before deciding whether to bring two astronauts back to Earth on Boeing’s spacecraft or extend their stay on the International Space Station until next year.

Boeing’s Starliner spacecraft, stricken by suspect thrusters and helium leaks, is taking up a valuable parking spot at the space station. It needs to depart the orbiting research complex, with or without its two-person crew, before the launch of SpaceX’s next Dragon crew mission to the station, scheduled for September 24.

“We can juggle things and make things work if we need to extend, but it’s getting a lot harder,” said Ken Bowersox, associate administrator of NASA’s spaceflight operations directorate. “With the consumables we’re using, with the need for the use of the ports for cargo missions, those types of things, we’re reaching a point where that last week in August, we really should be making a call, if not sooner.”

Last week, NASA officials said they expected to make a decision in mid-August—presumably this week—but Bowersox said Wednesday NASA probably won’t make the final call on what to do with the Starliner spacecraft until the end of next week, or the beginning of the week of August 26.

“We’ve got time available before we bring Starliner home and we want to use that time wisely,” Bowersox said.

NASA astronauts Butch Wilmore and Suni Williams launched inside Boeing’s Starliner spacecraft on June 5. Their mission is the first crew test flight on Boeing’s capsule before NASA clears Starliner for regular crew rotation flights to the space station. But after software setbacks, parachute concerns, and previous problems with its propulsion system, Boeing’s Starliner program is running more than four years behind SpaceX’s Dragon crew spacecraft, which flew astronauts to the station for the first time in 2020.

And now, there’s a significant chance the Starliner crew won’t come home in the spacecraft they launched in. Bowersox, a former astronaut, said NASA brought in propulsion experts from other programs to take a fresh look at the thruster issue.

Engineers are still investigating the root cause of why five of Starliner’s 28 reaction control system thrusters, supplied by Aerojet Rocketdyne, failed during approach to the space station the day after launch. The thrusters overheated as they pulsed over and over again to fine-tune the ship’s rendezvous with the station. Tests of a similar control jet on the ground suggested a Teflon seal in an internal valve could swell at higher temperatures, restricting the flow of propellant to the thruster.

Four of the five thrusters that failed before Starliner docked at the station have recovered and generated near-normal thrust levels during test-firings last month. But many engineers at NASA aren’t convinced the thrusters will work normally on Starliner’s journey from the space station back to Earth. These control jets are needed to keep the spacecraft pointed in the right direction when four larger rocket engines fire for the deorbit burn to steer the capsule on a trajectory back into the atmosphere for landing.

Rapid pulses of the thrusters, coupled with a long firing of the four larger engines, could raise temperatures inside four doghouse-shaped propulsion pods around the perimeter of Starliner’s service module. Once the deorbit burn is complete, Starliner will jettison the service module to burn up in the atmosphere, and its crew module will use a different set of thrusters to guide its reentry. Then, it will deploy parachutes to slow for landing, likely at White Sands, New Mexico.

Elevated risk

Bowersox said the outside engineers brought in from other NASA centers have, so far, largely agreed with the assessments made by the team working full time on Starliner.

“There are a lot of folks out there that have worked with similar thrusters, and have seen similar issues,” he said. “So we’ve gotten feedback on what we’re seeing, and a lot of it is confirming what we thought was causing the signatures that we were observing on orbit. It’s really tough when you don’t have the actual hardware to look at, when it’s up in space.”

During a news conference on Wednesday, NASA officials for the first time publicly discussed divisions within the agency about whether the Starliner spacecraft is really reliable enough to return two veteran astronauts—Butch Wilmore and Suni Williams—back to Earth from the International Space Station.

The space agency also confirmed key elements exclusively reported by Ars over the past week, chiefly that NASA has quietly been working for weeks with SpaceX on a potential rescue mission for Wilmore and Williams, that the Crew-9 mission launch has been delayed to September 24 to account for this possibility, and that Starliner is unable to undock autonomously with the current software configuration on the vehicle.

The chief of space human spaceflight operations for NASA, former astronaut Ken Bowersox, said no final decisions have been made on how Wilmore and Williams return to Earth. He said there were reasonable disagreements among engineers at NASA, which is the customer for the spaceflight, and Boeing, which developed and operates Starliner, about the viability of the 28 reaction control system thrusters that are used for delicate maneuvering and pointing of the vehicle.

“I think it’s been very healthy,” Bowersox said of these internal discussions during a call with reporters on Wednesday. “I have to admit that sometimes when we get disagreement, it’s not fun. It can be painful having those discussions, but it’s what makes us a good organization.”

NASA has been studying various contingencies, but officials appear to have settled on two different options for bringing the two astronauts back to Earth. They could still fly back on Starliner if NASA engineers become more comfortable with the uncertainty about the thruster performance, and if so, they would do so during the second half of this month or the first part of September. Alternatively, NASA could launch the Crew-9 mission with a complement of two rather than four astronauts, and Wilmore and Williams would join that “increment” on the space station and fly back to Earth in February 2025.

Asked if he thought one of the two scenarios was more likely than the other, Bowersox said he could not say. However, a final decision will be made fairly soon. Bowersox said NASA needs to choose the astronauts’ return path by mid-August.

Thruster Issues

NASA’s concern about Starliner’s thrusters boils down to the failure of five of them during the vehicle’s ascent to the space station. Starliner’s flight computer shut off five thrusters, provided by Aerojet Rocketdyne, in flight. Four of the five thrusters were recovered after overheating.

Since then Boeing and NASA have conducted ground- and space-based tests of the small thrusters to try to replicate the failure and better understand, fundamentally, what is occurring. By getting to the root cause, the engineers will feel confident in their ability to address the problem for Starliner’s flight back to Earth.

In ground tests, the engineers were able to demonstrate similar failures. Subsequent inspections showed bulging in a Teflon seal in an oxidizer valve known as a “poppet,” which could restrict the flow of nitrogen tetroxide propellant. The thrusters consume the nitrogen tetroxide and mix it with hydrazine fuel for combustion. Despite the tests, however, engineers still don’t understand precisely why the bulging is occurring and whether it will manifest on Starliner’s flight back to Earth.

“People really want to understand the physics of what’s going on relative to the physics of the Teflon, what’s causing it to heat up, and what’s causing it to contract,” said Steve Stich, who manages the Commercial Crew program for NASA. “That’s really what the team is off trying to understand. I think the NASA community in general would like to understand a little bit more of the root cause.”

It has now been eight weeks since Boeing’s Starliner spacecraft launched into orbit on an Atlas V rocket, bound for the International Space Station. At the time NASA officials said the two crew members, Butch Wilmore and Suni Williams, could return to Earth as soon as June 14, just eight days later.

Yes, there had been some problems on Starliner’s ride to the space station that involved helium leaks and failing thrusters. But officials said they were relatively minor and sought to downplay them. “Those are pretty small, really, issues to deal with,” Mark Nappi, vice president and manager of Boeing’s Commercial Crew Program, said during a post-docking news conference. “We’ll figure them out for the next mission. I don’t see these as significant at all.”

But days turned to weeks, and weeks turned to months as NASA and Boeing continued to study the two technical problems. Of these issues, the more pressing concern was the failure of multiple reaction control system thrusters that are essential to steering Starliner during its departure from the space station and setting up a critical engine burn to enter Earth’s atmosphere.

In the last few weeks, ground teams from NASA and Boeing completed testing of a thruster on a test stand at White Sands, New Mexico. Then, last weekend, Boeing and NASA fired the spacecraft’s thrusters in orbit to check their performance while docked at the space station. NASA has said preliminary results from these tests were helpful.

Dragon Becomes a Real Option

One week ago, the last time NASA officials spoke to the media, the agency’s program manager for commercial crew, Steve Stich, would not be drawn into discussing what would happen should NASA conclude that Starliner’s thrusters were not reliable enough for the return journey to Earth.

“Our prime option is to complete the mission,” Stich said one week ago. “There are a lot of good reasons to complete this mission and bring Butch and Suni home on Starliner. Starliner was designed, as a spacecraft, to have the crew in the cockpit.”

For a long time, it seemed almost certain that the astronauts would return to Earth inside Starliner.

However, there has been a lot of recent activity at NASA, Boeing, and SpaceX that suggests that Wilmore and Williams could come home aboard a Crew Dragon spacecraft rather than Starliner. Due to the critical importance of this mission, Ars is sharing what we know as of Thursday afternoon.

One informed source said it was greater than a 50-50 chance that the crew would come back on Dragon. Another source said it was significantly more likely than not they would. To be clear, NASA has not made a final decision. This probably will not happen until at least next week. It is likely that Jim Free, NASA’s associate administrator, will make the call.

Asked if it was now more likely than not that Starliner’s crew would return on Dragon, NASA spokesperson Josh Finch told Ars on Thursday evening, “NASA is evaluating all options for the return of agency astronauts Butch Wilmore and Suni Williams from the International Space Station as safely as possible. No decisions have been made, and the agency will continue to provide updates on its planning.”

Putting Together Puzzle Pieces

What follows are some data points that Ars can confidently report based on multiple sources:

• NASA keeps delaying a decision. A Flight Readiness Review meeting had been scheduled for today, August 1, several days in advance. However, it was canceled. Instead, NASA put out a vague blog update on Thursday stating, “Following the completion of Starliner’s return planning, which is expected to continue into next week, more information will be shared about the agency’s return readiness review preparations and subsequent media briefing.” So maybe the meeting will take place next week.
• NASA issued a $266,678 task award to SpaceX on July 14 for a “special study for emergency response.” NASA said this study was not directly related to Starliner’s problems, but two sources told Ars it really was. Although the study entailed work on flying more than four crew members home on Crew Dragon—a scenario related to Frank Rubio and the Soyuz MS-22 leaks—it also allowed SpaceX to study flying Dragon home with six passengers, a regular crew complement in addition to Wilmore and Williams.
• SpaceX has been actively working on a scenario in which two or four astronauts launch on board Crew 9. (A normal crew is four) This mission has a nominal launch date of August 18, but it could well be delayed. SpaceX has already identified flight suits that would fit Wilmore and Williams, allowing them to fly home on the Crew-8 spacecraft (presently docked to the space station) or the Crew-9 vehicle. It is unclear how crews would be assigned to the two Dragon return flights. It is possible, if four astronauts launch on Crew 9, that five people could fly home on each of the two Dragons.
• Two sources told Ars that in meetings this week at NASA field centers, there have been vigorous discussions about whether or not to fly crew home on Starliner. Multiple groups remain “no” on Starliner as of Wednesday. It is unclear how this will be resolved. Some engineers believe that if there are questions about Starliner, then NASA should opt for the safe course—flying on Crew Dragon, which has safely launched 13 times and landed 12 times.

The Toughest of Calls

NASA officials face a difficult decision. Because there is still at least a small risk to flying Starliner in its present condition, the space agency and Boeing have tested the thrusters as thoroughly as possible while the spacecraft is docked to the space station. This testing was intended to “buy down” these risks. But while the data is good, it has not addressed all of NASA’s concerns.

So what will the space agency do? Starliner probably could make it back to Earth safely. But there appears to be some reasonable doubt that Starliner will come back safely. If NASA defers to its fallback plan, flying on Dragon, it may spell the end of the Starliner program. During the development and testing of Starliner, the company has already lost $1.6 billion. Reflying a crew test flight mission, which likely would be necessary should Starliner return autonomously, would cost much more. Boeing might opt to cancel Starliner and leave NASA with just a single provider of crew transportation. That would be painful for both NASA and Boeing.

But the alternative—Starliner not coming home safely with the crew inside—is far, far worse. This is the risk-reward decision that Free, Stich, and other NASA officials ultimately must balance in the coming days.

This story originally appeared on Ars Technica.