A United Launch Alliance Atlas V rocket with Boeing’s Starliner spacecraft atop illuminated by spotlights on the launch pad of Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida is photographed ahead of the NASA’s Boeing Crew Flight Test, the first Starliner mission to send astronauts to the International Space Station as part of the agency’s Commercial Crew Program. Photo credit: NASA/ Joel Kowsky
NASA’s Boeing Crew Flight Test now is targeted to launch no earlier than 6:16 p.m. EDT Friday, May 17, to the International Space Station. Following a thorough data review completed on Tuesday, ULA (United Launch Alliance) decided to replace a pressure regulation valve on the liquid oxygen tank on the Atlas V rocket’s Centaur upper stage.
ULA plans to roll the rocket, with Boeing’s Starliner spacecraft, back to its Vertical Integration Facility at Cape Canaveral Space Force Station in Florida on Wednesday, May 8, to begin the replacement. The ULA team will perform leak checks and functional checkouts in support of the next launch attempt.
The oscillating behavior of the valve during prelaunch operations, ultimately resulted in mission teams calling a launch scrub on May 6. After the ground crews and astronauts Butch Wilmore and Suni Williams safely exited from Space Launch Complex-41, the ULA team successfully commanded the valve closed and the oscillations were temporarily dampened. The oscillations then re-occurred twice during fuel removal operations. After evaluating the valve history, data signatures from the launch attempt, and assessing the risks relative to continued use, the ULA team determined the valve exceeded its qualification and mission managers agreed to remove and replace the valve.
Mission managers discussed the details leading to the decision to scrub the May 6 launch opportunity during a news conference shortly after the scrub call at NASA’s Kennedy Space Center in Florida.
Wilmore and Williams will remain in crew quarters at NASA Kennedy in quarantine until the next launch opportunity. The duo will be the first to launch aboard Starliner to the space station as part of the agency’s Commercial Crew Program.
Starliner technicians work on the Orbital Flight Test-2 spacecraft in the high bay of Boeing’s Commercial Crew and Cargo Processing Facility at NASA’s Kennedy Space Center in Florida on Jan. 13, 2022.
NASA and Boeing continue making progress toward the agency’s upcoming Starliner Orbital Flight Test-2 (OFT-2) mission to the International Space Station as part of NASA’s Commercial Crew Program.
Teams recently completed offloading fuel from the OFT-2 spacecraft inside Starliner’s production factory at NASA’s Kennedy Space Center in Florida in preparation for separating and replacing the current service module (SM2) from the crew module.
“The Starliner team and successful completion of the spacecraft’s development phase are critical to sustaining International Space Station operations through 2030,” said Steve Stich, manager, NASA Commercial Crew Program. “The team’s dedication to developing effective remedies and corrective action after our first OFT-2 launch attempt demonstrates their continued commitment to safely flying NASA crews for years to come.”
In December, Boeing decided to move up service modules currently in production for its upcoming uncrewed and crewed flight tests. The service module originally planned for the Crew Flight Test (CFT) is now being used for OFT-2, and the service module originally planned for Starliner’s first post-certification mission, Starliner-1, now will be used for CFT.
With fuel offload complete, the spacecraft was moved out of the hazardous processing area and into the production factory high bay.
“Because this is not an operation that we normally perform, our team took the time to fully coordinate and assess the proper spacecraft and ground support equipment configurations, and then execute to plan to ensure the safety of our team,” said John Vollmer, vice president and program manager, Boeing’s Commercial Crew Program.
Once separated in the coming weeks from the OFT-2 crew module, SM2 will be sent to NASA’s White Sands Test Facility in New Mexico for additional testing related to the issue affecting the spacecraft’s oxidizer isolation valves.
The investigation into the valve issue continues to substantiate that the most probable cause is interaction of moisture with nitrogen tetroxide that permeates through the Teflon seal in the valve, leading to corrosion. Testing continues to fully understand how this occurrence affects the valves in various environments.
Tests include environmental seal evaluation and exposing valves, in a controlled setting, to temperatures and conditions similar to those the spacecraft experienced prior to the planned launch of OFT-2. The results of these tests will help in the ongoing development of remediation efforts to prevent similar issues on future service modules.
For example, the team designed a purging system that will be integrated into the spacecraft to protect the valves from potential exposure to moisture at the factory, launch complex, and launch pad.
Progress also continues with production of the new service module (SM4) that will go onto the OFT-2 crew module. That service module was recently moved from the low bay production area to the factory’s hazardous processing area for high pressure leak testing. Remaining tasks before mating this service module with the OFT-2 crew module include acceptance testing, final wire harness mating, installation of solar array panels, and final closeouts.
NASA and Boeing continue to work toward an opening in United Launch Alliance’s launch window availability in May for OFT-2. An actual launch date will be determined closer to spacecraft readiness, and with consideration of Eastern Range and International Space Station availability. Potential launch windows for CFT are under review and will be determined after a safe and successful OFT-2.
A United Launch Alliance Atlas V rocket with Boeing’s CST-100 Starliner spacecraft onboard is seen on the launch pad on Thursday, July 29, 2021, at Space Launch Complex 41 in preparation for the Orbital Flight Test-2 (OFT-2) mission at Cape Canaveral Space Force Station in Florida. Photo Credit: (NASA/Aubrey Gemignani)
NASA and Boeing are continuing to work through steps to determine what caused the unexpected valve position indications on the CST-100 Starliner propulsion system.
The United Launch Alliance Atlas V with the Starliner spacecraft on top will be returned to its Vertical Integration Facility (VIF) at Launch Complex-41 on Cape Canaveral Space Force Station Thursday where engineers will have direct access to Starliner for continued troubleshooting.
The data will drive any corrective measures that may be necessary to ensure Starliner is ready for launch. When NASA’s Commercial Crew Program and Boeing Space agree the issue is resolved, a new launch opportunity will be selected, taking into account the readiness of all parties involved.
“The Boeing and NASA teams are working methodically to understand what caused the valve indications on the Starliner service module propulsion system,” Steve Stich, manager of the Commercial Crew Program, said. “The troubleshooting in the Vertical Integration Facility will help focus on potential causes and next steps before we fly the OFT-2 mission.”
Early in the launch countdown for the Tuesday, Aug. 3 launch attempt, engineers detected indications that not all of Starliner’s propulsion system valves were in the proper configuration needed for launch of the company’s second uncrewed orbital flight test to the International Space Station, a mission designed to test the end-to-end capabilities of the crew-capable system as part of NASA’s Commercial Crew Program.
Mission teams decided to halt the countdown to further analyze the issue, which was conducted later Tuesday via several steps to troubleshoot the incorrect valve indications, including cycling the service module propulsion system valves.
After presenting the data to NASA and Boeing managers, it was decided to relocate the Atlas V and Starliner to the VIF for further inspection and testing where access to the spacecraft is available. Engineering teams have ruled out a number of potential causes, including software, and the direct access is required to continue the assessment.
“This mission is extremely important for the Commercial Crew Program on the path to the Boeing Crewed Flight Test,” Stich said. “We will fly the mission when we are ready. I am extremely proud of the NASA and Boeing teams for their professionalism, perseverance, and methodical approach to solving complex problems.”
NASA and Boeing will take whatever time is necessary to ensure Starliner is ready for its important uncrewed flight test to the space station and will look for the next available opportunity after resolution of the issue.
