NASA and SpaceX halt launch of Dragon to study hydrazine issue

NASA and SpaceX have postponed the launch of the Cargo Dragon spacecraft by at least two weeks due to a problem while preloading the high-powered thrusters.

The space agency had been planning to launch the spacecraft on June 12, but announced the delay in an email Monday night to reporters.

“During the thrust loading of the Cargo Dragon spacecraft, elevated vapor readings of monomethyl hydrazine were measured in an isolated region of the Draco thruster system,” the space agency said in a statement. “The propellant and oxidizer were discharged from that area to support further inspections and testing.”

Draco engines provide thrust to maneuver in orbit for the Dragon spacecraft. NASA said it is working with SpaceX to identify the source of the elevated readings and take any corrective actions. On Tuesday morning, Mission Control in Houston notified astronauts aboard the International Space Station that the launch date would be pushed back until at least June 28.

This is not the new Dragon vehicle. Designated as the “C208” Dragon, this vehicle previously performed two supply missions, both in 2021. It is an upgraded version of the original Cargo Dragon spacecraft, known as “Cargo Dragon 2.”

NASA will want to study this issue carefully, because the propulsion system in this Cargo Dragon version has much in common with the Crew Dragon, which also uses Draco thrusters and the same propellant. There should be plenty of time for this to work, however, as the launch of the upcoming Crew Dragon, which bears the “Crew 5 mission,” isn’t scheduled until September.

These Draco thrusters have much less thrust than the SuperDraco thrusters that are used to power the Crew Dragon’s launch escape system. During a test conducted in April 2019, an oxidizing agent leak occurred just before the ignition of the SuperDraco thrusters. led to an explosion that destroyed a spacecraft. No one is hurt.

The Cargo Dragon doesn’t have these SuperDraco engines, but nevertheless, NASA and SpaceX will want to understand all the issues with the latest leak before they release supplies or people.