On Thursday, November 5th, SpaceX fruitfully launched its Falcon 9 mission with the fourth GPSII satellite at 23:24 UTC (18:24 EST). The launch came after a scrub on October 2nd when it was forced to abort two seconds before take-off. A fault with the gas generators on several first-stage engines was discovered as a consequence of the study, which resulted in several engine replacements across the Falcon 9 fleet and impacted multiple scheduled launches.
The flight took off from the Cape Canaveral Air Force Station in Florida’s Space Launch Complex 40 (SLC-40). The Falcon 9 first stage landed on of Course I Still Love You, one of SpaceX’s Autonomous Spaceport Drone Ships in the Atlantic Ocean, after the initial ascent. On October 31, the drone ship departed Port Canaveral and was stationed 635 kilometers downrange, northeast of Florida.
The GO Ms. Chief, one of SpaceX’s fairing salvage ships, deceased Port Canaveral on November 3 and is currently positioned downrange. Because there is only one ship backup this launch, at least one fairing portion will be recovered rather than collected after splashdown. The GO Ms. Tree, the other fairing retrieval ship, is still docked in Port Canaveral for maintenance. With the NROL-101 mission, the eastern range is directing both this launch and an Atlas V. On Wednesday, NROL-101 was canceled due to a problem with the ground system’s liquid oxygen valves. The launch has been pushed out until Sunday.
B1062, a brand new Falcon 9 core, is the first stage supporting this mission. Prior to the aborted launch attempt on October 2, the stage successfully passed a static fire test at SLC-40 on September 25. The T-2 second abort was caused by an “unexpected surge in the turbomachinery gas generator,” according to SpaceX CEO Elon Musk.
A problem with numerous first-stage engines on numerous new Falcon 9 boosters was discovered during SpaceX’s study. B1061, the first stage supporting the next B1063, and Crew-1 mission, which is scheduled to take off the Sentinel-6 satellite from Vandenberg, California, were also damaged. As the launch customer for both Crew-1 and Sentinel-6, also the future CRS-21 mission, NASA was intimately involved in the study.
During a Crew-1 mission briefing, Vice President of Build and Flight Reliability for SpaceX Hans Koenigsmann, went into greater detail on the problem. In the first stage, two of the Merlin 1D engines started early during the abort on October 2. A strong start, which could have destroyed the engines, was avoided thanks to an autonomous abort.
Both engines were delivered to SpaceX’s McGregor, Texas plant for testing. A relief valve was discovered to be congested by leftover masking material from the engine’s manufacturing process, according to the study. “It’s kind of like nail polish,” Koenigsmann said of the substance. Only a few of the most recent Merlin engines are affected by the problem.
The binary engines on B1062 that had difficulty during the abort have been changed for the next launch attempt as a result of the inquiry. On B1063, an engine was also changed, as were two engines on B1061. Following the launch of the GPS-III-SV04, a detailed data evaluation will be used in the Flight Readiness Review for the forthcoming Crew-1 mission, as well as future missions.
On October 31, Booster B1062 executed supplementary static fire at SLC-40 to verify the fix. Previous US Department of Defence flights, such as the GPS-III-SV04 mission, necessitated the use of upgraded Falcon 9 boosters. The US Air Force has now cleared the use of salvaged promoters on the SV06 and GPS-III-SV05 missions, marking the first time that SpaceX will be able to use flight-proven stages on a national security mission. Prior to this certification, the Department of Defence was the last major SpaceX client that required fresh boosters, as NASA allowed Crew Dragon assignments to launch on refurbished Falcon 9s. The US military’s decision may pave the way for similar tactics for other SpaceX national security missions.
The launch client asked that Falcon 9 fly in an expendable mode, without landing grid fins or legs, when SpaceX launched their first GPS III mission. After a successful launch without a first-stage recovery attempt, SpaceX was given permission to try stage one recoveries on upcoming GPS launches. After launching GPS-III-SV03, Falcon 9 B1060 was positively improved aboard Just Read the Instructions. On September 26, a similar drone ship departed Port Canaveral for supporting the launch of SV04. Just Read the Instructions will be stationed 635 kilometers downrange, northeast of Cape Canaveral, at the time of launch.