A SpaceX cargo mission to the International Space Station has been pushed back to no earlier than July 11 after teams discovered elevated vapour levels of propellant. The mission was originally scheduled for launch on June 10, but ground teams noticed a potential hydrazine leak while loading cargo.
On Monday, officials with NASA met with SpaceX to discuss the findings of an investigation into the problematic vapour leak. Following additional inspections and testing of the Dragon spacecraft, the investigators managed to identify the source of the leak as being a faulty Draco thruster valve inlet joint, which controls the flow of propellant. The Dragon spacecraft has 16 Draco thrusters that manoeuvre it in orbit, and each thruster has two valve inlet joints used for fuel.
“Teams will now remove the specific hardware to replace it ahead of flight,” NASA wrote. “NASA and SpaceX are now targeting no earlier than July 11 for launch of the CRS-25 cargo resupply mission.”
This marks the second delay for the cargo resupply mission, the first delay being announced on June 6. The first delay happened after ground teams detected elevated vapour readings of mono-methyl hydrazine while loading the propellant, forcing them to stand down from the launch attempt. Last week, NASA targeted June 28 for the rescheduled launch. The revised launch date of July 11 now means CRS-25 will have been delayed by a full month.
The CRS-25 mission is slated to be SpaceX’s 25th uncrewed resupply mission to the ISS, which is part of the ongoing partnership between NASA and the private space company to launch science payloads to the orbiting space lab. SpaceX is also working under a commercial crew contract to transport astronauts to the ISS, which it has now done on four occasions.
The NASA and SpaceX partnership continues to be a strong one. The space agency recently bought five additional Crew Dragon flights to the ISS after NASA’s other commercial partner, Boeing, failed to deliver its own crew vehicle on schedule. The recent glitch with Crew Dragon, it’s fair to say, likely won’t have much of a bearing on this fruitful working relationship.