NASA has released a sweeping investigation report into the propulsion system failures that plagued Boeing’s CST-100 Starliner during its Crewed Flight Test (CFT) last year. The report finds a cascade of hardware failures, qualification gaps, organizational breakdowns, and a culture that prioritized schedule and provider success over engineering rigor in the program.
NASA announced today that Starliner will undock from the International Space Station September 6th and return to Earth September 7th.
Starliner launched on June 5th for what was originally planned to be an eight day mission. Since that time, Boeing, NASA and Aerojet Rocketdyne have been assessing issues with Starliner’s service module thrusters and working towards a decision whether to return with or without Butch Wilmore and Suni Williams, the two NASA astronauts who launched aboard the spacecraft.
The decision was made last week to return Starliner uncrewed and today’s announcement sets the stage for the end of Boeing’s part of the Starliner Crewed Flight Test. Williams and Wilmore remain aboard ISS, and will join Crew-9’s roster when it arrives at Station in late September. That mission will be flown using a SpaceX Crew Dragon.
NASA and Boeing concluded a detailed Delta-Flight Test Readiness Review on Thursday, polling “go” to process with undocking of the uncrewed Starliner spacecraft no earlier than 6:04 p.m. EDT of Friday, Sept. 6, from the International Space Station, pending weather and operational readiness.
After undocking, Starliner will take about six hours to reach the landing zone at White Sands Space Harbor in New Mexico. The spacecraft will touch down about 12:03 a.m. on Saturday, Sept. 7, descending under parachutes and with inflated airbags to cushion the impact. Recovery teams at the landing will safe and prepare the spacecraft for a return to Boeing’s Starliner factory at Kennedy Space Center in Florida.
NASA, August 29, 2024
The neverending story of the Boeing Starliner Test Flight continues, and NASA held a press briefing today to update the press and the public about progress toward resolving the troubled test flight. The news, in two words, is “no news.”
NASA is still studying Starliner data, still working to understand exactly what the current and future situation is with Starliner and whether it is safe to return the two astronauts aboard the spacecraft. Meanwhile, parallel work on other options continues: software changes are in process, and NASA and SpaceX are still determining the best way to return the Boeing CFT astronauts on Crew Dragon.
While there was decision announced today, the tone and tenor of NASA officials suggested that on may well be coming soon, as the port Starliner is currently docked at will soon be needed for other missions.
In parallel to data analysis and risk assessments of Starliner, NASA is working on testing and then updating Starliner’s software to fly autonomously, if needed, is continuing to develop plans to return the crew on Crew Dragon, and preparing for CFT astronauts to become Expedition Crew in the meantime. The astronauts are healthy and fine, are integrated into ISS activities and workloads, and say they are relying on ground controllers to make the right call.
While NASA continues their analysis and deliberations behind the scenes even though it looks like nothing much is going on from an outside perspective. That’s far from the case as mission managers, scientists and engineers from across the spectrum of NASA’s technology portfolio and from Boeing and associated contractors are working on this issue. In short, don’t be fooled by the quiet on the surface and any lack of announcements, NASA is conducting a thorough analysis as quickly as possible.
The press conference opened with Ken Bowersox, a former astronaut and the associate administrator for NASA’s Space Operations Mission Directorate stating plainly that, “We don’t have any major announcements today.” In other words, no decision on how and when Starliner Crewed Flight Test astronauts Butch Wilmore and Suni Williams will return to Earth.
Bowersox also said, “Our technical experts are all busy, diving deeply into all the data that’s been generated over the past few weeks, going through the feedback of new, propulsion system experts that have been brought in, looking at planning for our return options and, preparing for, some decision points that are ahead, at the program control board, and eventually a flight Readiness Review.”
That date of that Readiness Review has been shifted right, with Bowersox saying, “A flight readiness review around the end of next week, potentially beginning of the following week.” He added that NASA has the luxury of time on its side in order to come to a consensus, conclusion and a final decision, but that time is starting to run out.
When asked about the extended presence of Starliner on one of the very few docking ports at ISS, Bowersox said, “We can juggle things and make things work if we need to extend, but it’s getting a lot harder. With the consumables we’re using, with, the need for the use of the ports for cargo missions, we’re reaching a point where that last week in August, we really should be making a call, if not sooner.”
Joe Acabá gave the following remarks today: “We undergo rigorous training to prepare, both mentally and physically for the challenges that may arise during any given mission. This mission is a test flight, and as Butch and
Suni expressed ahead of their launch, they knew this mission might not be perfect. Human spaceflight is inherently risky, and as astronauts, we accept that as part of the job.”
He continued, “Right now, the agency has taken the time to ensure we are not putting the crew at a higher risk than is necessary. And as astronauts, that’s always something worth waiting for. As Starliner’s first flight with crew, Butch and Suni gave the ground teams feedback and data on the spacecraft, both during the write-up and now docked to the International Space Station.”
“That added human element continues to be extremely helpful for our teams on the ground. Butch and Suni have also contributed to countless hours of science and research, which I know our ISS program is very thankful for.”
“As most of you know, Butch and Suni are very familiar with life aboard the space station. This is their third station mission for both of them.”
“I do want to put this into perspective. If Butch and Suni do not come home on Starliner and they are kept aboard the station. They will have about eight months on orbit. We have done multiple successful long duration. Missions, even up to a year. Those missions have given us volumes of data about the effects of long duration spaceflight that we continue to use in space exploration.”
“As I assign crew members to a flight and before they launch, we discuss nominal and potential off nominal mission durations. They are always prepared. We are lucky to be in a time in human spaceflight where we have regular resupply missions, enabling the crews aboard the station to receive any extra supplies they may need, and where an eight month mission falls within our standard long duration mission timeframe.”
“I’ve talked to Butch and Suni a number of times throughout their stay, and they continue to be committed to the mission. They are proud to represent our nation, and they continue to show their readiness and resilience. We are proud of all of our current expedition crew aboard the International Space Station as we work through this process.”
“We are proud of the teams on the ground, and we know our CFT crew, Butch and Suni, will be ready to support the direction our agency chooses.”
NASA managers say they are close to a decision on when and how they plan to bring Boeing Starliner Crewed Flight test astronauts from the International Space Station. The mission was originally slated to run eight days, but the pair have been in orbit for sixty-three days since their June 5th launch from Cape Canaveral Space Force Station aboard an Atlas V.
“I don’t think we’re too far away from making that call,” Ken Bowersox, NASA’s Associate Administrator for Space Operations Mission Directorate said this afternoon. He added, “We know that at some point we need to bring Butch and Suni home [but] while they’re up there, we have extra crew, we have extra hands, they can do a lot more work, but they’re also using up more consumables, more supplies.”
“As we’ve said before, our prime option is to return Butch and Suni on Starliner, however, we have done the requisite planning to make sure we have other options open.”
Steve Stich, NASA’s Manager for the Commercial Crew Program, August 7, 2024
Bowersox added that Williams and Wilmore may not return on the Starliner spacecraft. “In the case that we have with the Starliner crew,” he said, “the option to either bring the crew home on the Starliner or to bring the crew home on another vehicle. We could take either path, and reasonable people could pick either path depending on where their view is on our position in the uncertainty bound that we have for the date.”
“We have been working with SpaceX to ensure that they are ready to respond on Crew 9 for a contingency of returning Butch and Suni on Crew 9,” Bowersox said. “If we need that we have set up the [Crew] Dragon for Crew 9 to have flexibility to have only two passengers fly up on that flight.”
One thing that NASA did not disclose is which two of the Crew 9 crew would potentially be taken off the mission should the need arise. “We’re not really ready to share the data on which crew members,” said Steve Stich. “I think we’ll do that at the appropriate time.”
The reason for the uncertainty is well-documented: Starliner has thruster problems on its Service Module, and engineers and mission managers within NASA are not unanimous that the spacecraft can be safely flown until such time as the Starliner capsule would separate from its troubled SM and then begin re-entry.
Bowersox said, “We’ve got on the thruster system, on the propulsion system. Moving forward, what we’re trying to do is reduce that uncertainty, see if we can drive some more consensus, amongst our team at the same time getting more serious about evaluating our other options. It’s been really great to watch our team working, our Boeing team, our NASA team, the way people are speaking up; the way we’re hearing different voices, different thoughts on how critical different factors are in the decision.”
“I think it’s been very healthy,” Bowersox said, speaking about the debate behind the scenes. “I have to admit that sometimes when we get this agreement, it’s not fun. It can be painful having those discussions, but it’s what makes us a good organization and it’s what will get us to a good decision as we approach that point here in the future.”
“And I don’t think we’re too far away from making that call.”
Steve Stich, NASA’s Manager for the Commercial Crew Program, gave an in-depth rundown of the technical aspects of Starliner’s issues:
“I’ll talk a little bit more about the manifest changes we’ve made and what we’ve done to give ourselves some flexibility in the near term relative to all the options that we’re looking at. So, if we start with Starliner last time we talked a lot about testing results at White Sands, we had completed the thruster testing, which was essentially two uphill [ascent to ISS after launch] profiles trying to get to the temps that we saw on this particular thruster.”
“And then we really have done five downhill [undocking and free flight to reentry] profiles with that particular thruster. We were able to replicate degradation in the thruster during. That testing, and we saw that continually on the downhill side with the thruster thrust levels degrading over time, which seems to mimic what we’re seeing in flight to some extent during those downhill profiles, as we talked about during that testing, we gained insight into what we think one of the contributing factors are for that thrust degradation.”
Stich continued: “And that would be this Teflon seal on the oxidizer line poppet. Now, this poppet’s really small. It’s about, if you hold up your little pinky finger, it’s about the size of that. A little bit smaller even than your pinky finger. So it’s a small poppet. But what we saw during that testing is the swelling of that Teflon seal.”
“It kind of extruded a little bit. And what happens with that seal is it blocks the flow into the thruster itself, down into the combustion chamber. So we know that’s happening. We know we can get vaporization when it gets hot in that line, bringing propellant into the thruster.”
“And also when that poppet is blocked by the Teflon seal, we see some cavitation, in other words, unsteady flow across that poppet. We have some animation that we hope to be able to release soon to you. So you can see what this is like. Boeing has been doing a lot of work on that animation.”
“Hopefully, we can have them share that soon so you can get a better idea of that mechanism as well. We also have this same theory that has some vaporization of the propellant, right, and it drops the thrust. So there’s really two key things that we think is happening. One, when the thruster gets really hot, the propellant can vaporize.”
“That’s where we saw the really low thrust readings on docking day. And then as the poppet swells, we can get some blockage there. Based on what we learned at White Sands, what we’re trying to do now is sort of understand what all that data means to us from the white sands testing and then what it means to the thrusters on orbit.”
“We did do a hot fire while we’re docked to the International Space Station on Saturday, July 11. we wanted to understand the performance of all the thrusters across the vehicle. So we hot fired all 27 thrusters. We did not hot fire one thruster in the bottom doghouse.”
“We call it the B1-A3 thruster. That one had really low thrust before, during the dock when we were docking back on July 6. And so we did not. Or June 6, and we did not hot fire that thruster. The interesting thing when we hot fired the thrusters is all the thrusters now across the whole vehicle are essentially at nominal thrust level.”
“So, for example, the one that we saw the most degradation in the two. A two was at about 80% before the hot fire, and now it’s about 98%. So somehow, if the poppet is the theory of what’s causing the thrust degradation, the blockage in that ox flow, somehow that piece of Teflon must have contracted and is now not blocking the flow like it was.”
“And so we have a nominal flow, essentially, into that. Thruster and nominal thrust. What we’re really trying to do now, that gives us a lot of confidence in the thrusters, but we can’t totally prove with certainty what we’re seeing on orbit is exactly what’s been replicated on the ground.”
“We’re trying to understand a little bit more about the conditions that cause the thruster fail-offs. It’s not always at the same temperature. It’s not always at the same number of pulses. And so we’re trying to understand that we are doing modeling on the ground to try to understand how this Teflon could extrude what the forces are on that Teflon.”
“And then trying to understand how it could contract over time. 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, what’s causing it to contract. And that’s really what the team is off trying to understand. And then look ahead toward the downhill phase and the heating on the downhill phase and seeing if we can model that on the downhill phase and ensure we have good thrusters.”
“Again, we have really good knowledge of what the downhill is. But how does that really help us out?”
“In combination with that, we have tried to buy ourselves a little bit of time to work various options for return. And so recently, this week at the Program Control Board, just yesterday, we approved moving the Crew 9 mission to no earlier than September 24. We took that to the Program Control Board, and it was approved.”
— Steve Stich, August 7, 2024
“We have been working with SpaceX to ensure that they are ready to respond on Crew 9 for a contingency of returning Butch and Suni on Crew 9 if we need that. We have set up the dragon for Crew 9 to have flexibility to have only two passengers fly up on that flight,” Stich said.
“And then we could return four crew members in the February 2025 timeframe. And Butch and Suni would remain on station and become part of that increment and return home with them on Crew 9. Now, we haven’t approved this plan. In other words, we’ve done all the work to make sure this plan is there.”
“We have the suits identified to fly up on Crew 9. We have the seats set up so that we can fly multiple complement of people. But we have not turned that on formally, as that’s the path that we’re going to go down. But we wanted to make sure we had all that flexibility in place.”
“We’ll fly up the supplies needed on that Crew 9 flight, including any suits needed for butch and Suni. You know, we’ve done previous work with that for other contingencies. And we’ll have the foam inserts to work on all the seats for the various crew members.”
“So we’ve done a lot of contingency work and a lot of contingency planning for a lot of scenarios, but we think now we would have the whole waterfront covered. As I said, we haven’t really implemented planning for the mission for these things, but we have all the items in place to keep all the options on the table.”
That said, it appears that NASA is keeping its options open by thoroughly investigating and completing at least preliminary plans for the option of returning the Boeing Starliner CFT astronauts on a SpaceX Crew Dragon.
At the end of the press conference several things were clear: first, that NASA is undecided on whether to return Wilmore and Williams to Earth using Starliner, second, that there are disagreements within NASA about doing that, and third, that returning on a SpaceX Crew Dragon is a very real possibility with planning already started for that option as a contingency.
I was not able to be present at Cape Canaveral for the actual launch of Starliner due to prior commitments and the two previous scrubs of the flight moving the schedule into the middle of another long-planned trip. Disappointing, but things happen. I was, however, able to capture a lot of the prelaunch activities:
After a day of speculation and probably leaks of the information on background, NASA, Boeing and United Launch Alliance have announced that they are pushing the schedule back another four days for the Crewed Flight Test of Starliner. The launching will be “no earlier than 3:09 p.m. EDT Saturday, May 25, for the flight test carrying NASA astronauts Butch Wilmore and Suni Williams to the International Space Station,” according to a release from NASA.
As to the reason for the new delay, NASA stated:
“The additional time allows teams to further assess a small helium leak in the Boeing Starliner spacecraft’s service module traced to a flange on a single reaction control system thruster. Pressure testing performed on May 15 on the spacecraft’s helium system showed the leak in the flange is stable and would not pose a risk at that level during the flight. The testing also indicated the rest of the thruster system is sealed effectively across the entire service module. Boeing teams are working to develop operational procedures to ensure the system retains sufficient performance capability and appropriate redundancy during the flight. As that work proceeds, NASA’s Commercial Crew Program and the International Space Station Program will take the next few days to review the data and procedures to make a final determination before proceeding to flight countdown.“
NASA, Boeing Now Working Toward May 25 Launch of Crew Flight Test
Reading between the lines, it seems that the leak has not been repaired but is instead “stable.” NASA and Boeing now have to “assess” whether this is an acceptable condition for flight. That decision will be made in the next few days and then everyone will have a better idea of when Starliner can launch with crew aboard for the first time.
It was all going well until it wasn’t. That’s often the story with launch attempts: tens of thousands of things must work perfectly, perform as planned, and operate normally, and only one thing has to go wrong for the attempt to be called off.
That was the case with United Launch Alliance’s attempt to launch Boeing’s CST-100 Starliner this evening, and with about two hours left in a smooth-running countdown with astronauts already aboard Starliner, the launch attempt was scrubbed. A faulty valve on the Centaur upper stage of Atlas V malfunctioned, and flight rules dictated that the launch attempt be called off.
UPDATE May 7th 7PM: ULA, Boeing and NASA are now targeting Friday May 17th at 6:16 PM EDT for the next launch attempt of Atlas V and Starliner:
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