NASA has pushed the launch of the SpaceX Crew-1 mission to no sooner than early-to-mid November citing off-nominal behaviour of a Falcon 9 first stage during a recent non-NASA launch attempt.
The launch of the first operational SpaceX Crew Dragon mission had initially been scheduled for the end of the month. On October 10, Associate Administrator of NASA’s Human Exploration and Operations Mission Directorate, Kathy Lueders confirmed on Twitter that the agency was now targeting early-to-mid November.
In a statement published on the NASA Commercial Crew blog, the agency identified the reason for the delay as off-nominal behaviour of a Falcon 9 first stage engine gas generator during a recent non-NASA mission launch attempt. The mission in question is the GPS III-4 flight for the US Space Force that was automatically aborted just two seconds before liftoff on October 3.
Although there was no official statement from SpaceX following the last-minute abort, answering a question on Twitter, SpaceX founder and CEO Elon Musk revealed that there had been an “unexpected pressure rise in the turbomachinery gas generator.”
In order to pressurize its fuel (RP-1) and oxidiser (LOX), a SpaceX Merlin rocket engine utilises a turbopump that ramps the pressure from 50psi in the tanks to around 1000psi by the time they reach the combustion chamber. The engine uses a turbine to power the turbopumps which in turn relies on a gas generator for power.
The gas generator utilises small amounts of fuel and oxidiser which it burns separately from the main combustion chamber to power the turbine. The cause of the abort that the SpaceX GPS III-4 mission suffered has been narrowed down to this component in at least one of the nine Merlin 1D+ engines that power the Falcon 9 first stage.
According to Lueders, SpaceX is working closely with NASA to narrow down the problem and ensure the rocket is safe for crewed flight.
“We have a strong working relationship with our SpaceX partner,” Lueders said. “The teams are actively working this finding on the engines, and we should be a lot smarter within the coming week.”
Despite the off-nominal Falcon 9 first stage engine performance pushing back the launch of the Crew-1 mission, NASA has confirmed that several of its other missions that are scheduled to be launched aboard the Falcon 9 have not been affected.
SpaceX is set to launch the Sentinel-6 Michael Freilich mission on November 10, and the CRS-21 International Space Station resupply mission in late November. In an October 10 statement, NASA confirmed that it was working closely with SpaceX to review hardware testing data to “ensure these critical missions are carried out with the highest level of safety.”
The NASA SpaceX Crew-1 mission will carry NASA astronauts Michael Hopkins, Victor Glover, and Shannon Walker, and JAXA mission specialist Soichi Noguchi aboard the Crew Dragon Resilience. The spacecraft will rendezvous with the International Space Station and autonomously dock with the orbiting laboratory. The four-person crew will become part of Expedition 64 joining fellow NASA astronaut Kate Rubins and Roscosmos cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov.