What was originally planned to be around a week-long stay at the ISS has now been pushed back to an indefinite date. Late last night the agency made the decision to move off the June 26th departure date and are now working to figure out a possible return opportunity. Specifically, they want more time to review data related to the Helium leaks and thruster failures that occurred earlier in the mission.
While this helps teams gather data, Starliner only is rated for a total of 45 days docked to the station. That means that within the next few weeks, they either gather necessary data, deem the spacecraft safe, and send crew back to Earth on Starliner, or other options would be needed. As of right now, the agency is adamant that Starliner is safe and will soon bring the astronauts back home. Here I will go more in-depth into the new delay, what data the agency and Boeing are looking at, future departure opportunities, and more.
Unknown Return Date
Starliner launched on June 5th and docked to the ISS on the 6th. There was one helium leak before the launch, and then 4 more were found in orbit. In addition, 5 thrusters failed around the time of docking delaying an initial approach. Since then they have been testing and trying to figure out what caused these different issues. In a new statement, the agency said, “NASA and Boeing leadership are adjusting the return to Earth of the Starliner Crew Flight Test spacecraft with agency astronauts Butch Wilmore and Suni Williams from the International Space Station.” As far as why they did this they went on to say, “The move off Wednesday, June 26, deconflicts Starliner’s undocking and landing from a series of planned International Space Station spacewalks while allowing mission teams time to review propulsion system data.”
In other words, it’s presented more as there simply is a conflicting timeline with a few planned spacewalks and within that time we might as well continue to investigate some of the spacecraft’s data. “We are taking our time and following our standard mission management team process,” said Steve Stich, manager of NASA’s Commercial Crew Program. Interestingly, he then was quoted saying, “We are letting the data drive our decision making relative to managing the small helium system leaks and thruster performance we observed during rendezvous and docking. Additionally, given the duration of the mission, it is appropriate for us to complete an agency-level review, similar to what was done ahead of the NASA’s SpaceX Demo-2 return after two months on orbit, to document the agency’s formal acceptance on proceeding as planned” he said.
In terms of a new departure and landing date, there isn’t one yet. The original plan was for Starliner to dock to the station for about a week and then return likely around the middle of this month. Specifically, when Starliner first launched on the 5th, a specific return date wasn’t set. Instead, the agency commented that the mission was expected to last about one week. In other words, going into it, once Starliner had docked to the station, they had options in terms of how long they could stay, when they would depart, and even the exact landing location after reentry. With this in mind, the first real date we were provided came on June 9th. Here NASA said in a statement that “NASA and Boeing Space teams set a return date of no earlier than Tuesday, June 18, for the agency’s Boeing Crew Flight Test. This was eventually pushed back to the 22nd, then the 26th, and now indefinitely.
Based on NASA’s new statement from last night, it seems that the earliest we would see Starliner undock could be around early July. They were quoted saying, “Mission managers are evaluating future return opportunities following the station’s two planned spacewalks on Monday, June 24, and Tuesday, July 2.” This sounds as if the July 2nd spacewalk and its following days would be one of the earliest opportunities.
Despite this push back, Stich said, “Starliner is performing well in orbit while docked to the space station. We are strategically using the extra time to clear a path for some critical station activities while completing readiness for Butch and Suni’s return on Starliner and gaining valuable insight into the system upgrades we will want to make for post-certification missions” he said.
It’s important to point out that a lot of the issues Starliner has experienced up to this point have been within the service module. This is relevant because not long after undocking from the station, and soon before Earth reentry, the service module is jettisoned and burns up in the atmosphere. This means the only chance for NASA and Boeing to gather valuable data on this system and find out what’s going wrong, is now.
While all of this has been happening, the crew has been busy on the station. Mark Nappi, vice president and program manager, Boeing’s Starliner Program said, “The crew’s feedback has been overwhelmingly positive, and they know that every bit of learning we do on the Crew Flight Test will improve and sharpen our experience for future crews,” They also clarified that the crew is not pressed for time to leave the station since there are plenty of supplies in orbit, and the station’s schedule is relatively open through mid-August.
Focusing back on the current mission extension, Starliner has a 45-day limit at the ISS. That is, this vehicle is only rated for a 45-day stay at the space station. It’s worth noting that with it docking on the 6th, it has already been there for around 16 days. A departure around July 4 would have it close to 30. Based on what NASA and Boeing teams are saying, there should be very little chance of the vehicle not departing within the next few weeks.
At the same time, there seems to still be quite a bit of information related to the various issues that they need a better understanding of to prevent issues in the future. In total there were 5 helium leaks and 5 thruster failures. In the time since these popped up teams were able to hot fire the thruster and reactivate 4 of them. 1 however has been left off based on abnormal data. In regard to this Stich said, “Thruster B1A3 when we looked at that hot fire data we saw that it had 11% thrust on one of the firings and then 0% on another. These were the two firings that we did on the rendezvous day. That thruster we decided we are not going to hot fire that thruster anymore. We didn’t hot fire it on Saturday, we are just going to leave that thruster alone, because it shows a very strange signature where we’re getting almost no thrust out of that. So we are going to leave that thruster de-selected and are not going to use it for the rest of the flight” he said.
That thruster in particular is likely a strong point of focus for teams right now to find out exactly why its not working properly. It’s worth noting that they performed a hot fire last Saturday, which featured a short pulse on all 7 of the thrusters including 3 of the good thrusters that showed nominal behavior on rendevous day. Stich mentioned that during this test they saw very good chamber pressure when they fired. Specifically, they were around the 300 PSI mark, some were a little bit lower but for the most part they were good. He then said, “So coming out of that we feel very confident in the thrusters and the team is just making sure to look at the thrusters in detail and compare them to what happened on OFT-2. If you remember on OFT-2 during the rendezvous sequence, we had 2 thrusters fail. Both of those thrusters at the end of the flight and the team is looking at all that data and comparing it to OFT-2” he mentioned.
At this point, Starliner has definitely had a more eventful first-crewed flight than likely hoped for. While it is still a test flight, it could hurt the time between now and future crewed missions. This mission is hoping to certify the Starliner vehicle which would facilitate much more frequent crewed missions to and from the ISS. Boeing Starliner-1, also called Post Certification Mission-1, is planned to be the first operational crewed mission of the Boeing Starliner to the International Space Station as part of the Commercial Crew Program. This is scheduled to happen not long from now in 2025. However, with some of the complications during this flight, it could easily be delayed by quite a bit.
A few days ago Stich was asked about the Starliner-1 mission and he said, “I would say the whole team has been focused on understanding what’s happening with this vehicle for the crew flight test and our plan for return, so we haven’t looked ahead too much for Starliner 1. As Mark said we know we have to address the helium leaks. Were not going to go fly another mission like this with the helium leaks. We gotta go understand what the rendezvous profile is doing that is causing the thruster to have low thrust and then be de-selected by the flight control temps. So we got some of the work to do after this flight” he said.
When Starlienr does eventually undock from the station, there are a few mission milestones leading up to reentry that require the use of thrusters. The goal between now and the next return date is to ensure these systems are not only safe but find out exactly what’s wrong and prevent a similar issue from happening in the future.
Conclusion
Boeing and NASA have pushed back Starliner’s return to an indefinite date. What was recently changed to the 26th of this month now likely won’t be until early July. This is supposed to give them more time for research and tests before the service module is destroyed on Earth entry. We will have to wait and see how it progresses and the impact it has on the space industry.