NASA and SpaceX are standing down from this week’s Falcon 9 launch of the CRS-25 cargo mission to the International Space Station.
Officials from NASA and SpaceX met today to discuss an issue identified over the weekend and the best path forward.

During propellant loading of the Dragon spacecraft, elevated vapor readings of mono-methyl hydrazine (MMH) were measured in an isolated region of the Draco thruster propulsion system. The propellant and oxidizer have been offloaded from that region to support further inspections and testing. Once the exact source of the elevated readings is identified and cause is determined, the joint NASA and SpaceX teams will determine and announce a new target launch date.

In the meantime, Flight Engineers Jessica Watkins of NASA and Samantha Cristoforetti of ESA (European Space Agency) are getting up to speed with the Dragon cargo craft’s rendezvous and docking procedures. The duo trained on a computer on Monday to prepare for their roles when they monitor Dragon’s automated arrival and docking.

Eye exams were on the schedule with NASA Flight Engineer Kjell Lindgren taking charge as Crew Medical Officer today. He operated medical imaging gear, using standard optical coherence tomography techniques, and scanned the eyes and retinas of Cristoforetti and NASA Flight Engineer Bob Hines.

Before beginning his eye exam, Hines cleaned up and stowed obsolete combustion research hardware to make room for newer science gear being delivered on upcoming resupply missions. The first time space-flyer also worked on light orbital plumbing duties and recirculated fluids to support plants growing for the XROOTS space botany study.

Lindgren started his day in the Quest airlock servicing U.S spacesuits. The first time space-flyer collected water samples from the suit cooling loops and cleaned their water lines before installing new components. Watkins completed the spacesuit work in the afternoon following her Dragon rendezvous training.

In the station’s Russian segment, Commander Oleg Artemyev and Flight Engineer Sergey Korsakov took turns exploring ways to maximize and monitor the effectiveness of physical exercise in space. Artemyev also updated cargo inventory systems as Korsakov unpacked supplies from inside the new Progress 81 resupply ship. Flight Engineer Denis Matveev installed Earth observation gear before photographing the inside of the Nauka multipurpose laboratory module4 for inspection purposes.