File photo: SpaceX CRS-24 prepared for rollout to the launch pad. (Dec. 19, 2021)

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.

Astrorad: The crew gathered the appropriate items and prepared for the upcoming science activities. Comfort and Human Factors AstroRad Radiation Garment Evaluation (CHARGE) tests a special vest designed to protect astronauts from radiation caused by unpredictable Solar Particle Events (SPEs). Astronauts provide input on the garment as they wear it while performing daily tasks, including how easy it is to put on, how it fits and feels, and the range of motion it allows. Garment developers can use this input to improve design. The use of the vest will protect crew members on missions to the Moon and Mars.

Combustion Integrated Rack/Advanced Combustion via Microgravity Experiments (CIR/ACME): In a continuation of the activity started last week, obsolete ACME hardware was located, consolidated, and prepared for return or trash. The ACME series of experiments have been performed, and the ACME insert previously removed from the CIR to make room for the currently installed experiment insert known as the Solid Fuel Ignition and Extinction (SoFIE). CIR includes an optics bench, combustion chamber, fuel and oxidizer control, and five different cameras for performing combustion investigations in microgravity.

Cold Atom Lab (CAL): A crewmember performed a visual inspection of the CAL Moderate Temperature Loop (MTL) Jumper to check for leaks and reported leakage. The MTL Jumper has been susceptible to a small leak and periodic crew monitoring has been implemented while the ground assesses future remediation options. The CAL produces clouds of atoms that are chilled to about one ten billionth of a degree above absolute zero (much colder than the average temperature of deep space). At these low temperatures, atoms have almost no motion, allowing scientists to study fundamental behaviors and quantum characteristics that are difficult or impossible to probe at higher temperatures. In microgravity, researchers may be able to achieve even colder temperatures than what is possible on the ground and observe these cold atom clouds for longer periods of time.

eXposed Root On-Orbit Test System (XROOTS): In support of the current growout, the crew performed the manual water recovery activity in Root Modules (RM) 1 and 2. The XROOTS investigation uses hydroponic and aeroponic techniques to grow plants without soil or other growth media. Video and still images enable evaluation of multiple independent growth chambers for the entire plant life cycle from seed germination through maturity. Results could identify suitable methods to produce crops on a larger scale for future space missions.

ISS HAM pass: The crew participated in an ISS Ham event with Scuola media S.Pietro, Nuoro, Sardegna, Italy. Some of the questions asked by the students included if the crew believes there are other solar systems with life, if the crew listens to music and what kind of music is preferred, and if the crew would like to live or visit another planet if possible. ISS Ham Radio provides opportunities to engage and educate students, teachers, parents and members of the STEM community by providing a means to communicate between astronauts and the ground Ham radio units.

Light Ions Detector for ALTEA (LIDAL): LIDAL was moved to its second operational location. The capability of Anomalous Long-Term Effects in Astronauts (ALTEA) to measure the linear energy transfer (LET) of protons and helium and the kinetic energy of protons and heavy ions was upgraded by the addition of a new time of flight (TOF) system detector called LIDAL. LIDAL upgrades the ability of ALTEA to make measurements that can be converted, by dedicated software in real-time, into radiation risk coefficients - effectively enabling ALTEA to become the first ever dosimetric (risk meter) aboard the ISS.

Nutrition Monitoring for the International Space Station (NutrISS): In support of the NutrISS investigation, an European Space Agency (ESA) Nutritional Assessment (ENA) was performed. In the NutrISS investigation, a periodic assessment of body composition (body weight, fat mass, and fat-free mass) during spaceflight aboard the ISS is carried out using a dedicated bio-impedance analysis device to allow for the measurement of long-term energy balance modification over time. It is hypothesized that an adjusted diet maintaining a near-neutral energy balance, and/or increasing protein, intake can limit microgravity-induced bone and muscle loss.

Extravehicular Mobility Units (EMU) 3004/3015 Loop Scrub and Iodination: The crew performed EMU water loop scrubs and then acquired and tested water samples for conductivity on units 3004 and 3015. EMU Loop Scrubs are required preventive maintenance needed to remove any chemical and biological contaminants from the EMU transport loop.

Optical Coherence Tomography (OCT2) Exam: The crew completed routine OCT eye exams today. OCT is an imaging technique analogous to ultrasound imaging that uses light instead of sound to capture micrometer-resolution, two- and three-dimensional images of tissue; in this case, the objects of interest are the crewmembers' eyes. Eye exams are performed regularly on-board to monitor crewmembers' eye health. Eyesight is one of the many aspects of the human body that may be affected by long-duration stays in a microgravity environment.

SpaceX-25 Dragon Rendezvous Review: Today, crew completed a self-study familiarization training for Cargo Dragon rendezvous operations in preparation for the upcoming SpaceX-25 mission.

WPA Catalytic (Cat) Reactor Inspection and Preparation for Stowage: Today, the crew prepared the degraded Cat Reactor for stowage. The crew inspected the bottom cover of the Cat Reactor lid and cleaned the small amount of water found.

Fluidics restow in Starboard Endcone 81P USOS Unpack Today's Ground Activities: All activities are complete unless otherwise noted.

SSC XOI Service Pack Checkout PRO MELFI 1 Dewar Timeliner Configuration Commanding Laptop Preparation for OCT2 Exam Look Ahead Plan

AstroPi Vis Configuration AstroRad Vest Acoustic Diagnostics CBEF-L NutrISS XROOTS Systems:

Nitrogen Oxygen Recharge System (NORS) Oxygen Transfer Initiation Short Extravehicular Mobility Unit (SEMU) Launch Enclosure (SLE) Return Preparation SpaceX-25 Dragon Rendezvous Review PPE Audit Wednesday, June 8 (GMT 159) Payloads:

Astrobee Prep AstroRad Vest KUBIK MSG/Transparent Alloys Stow NutrISS Wanted Poster - Temp Logger Wireless Compose-2 Systems:

ARED Slider Assembly R&R Temperature and Humidity Control (THC) Intermodule Ventilation (IMV) Flow Measurement Survey Hatch Seal Inspection Cupola Window #7 Scratch Pane Installation Thursday, June 9 (GMT 160) Payloads:

Astrobee Astrorad Vest CBEF-L GHF Checkout NutrISS Rodent Research-22 Prep Systems:

SpaceX-25 Dragon review Node 3 Endcone Stowage Cleanout Dragon Cargo Operations Review Today's Planned Activities: All activities are complete unless otherwise noted.

ACME Hardware Consolidate AstroRad Vest Hardware Gather and Familiarization Cold Atom Lab MTL Jumper Leak Check Radiation Environment Monitor 2 (REM2) Reseat EMU Cooling Loop Scrub Deconfiguration EVA Hard Upper Torso Gather EMU Cooling Loop Maintenance Iodination EMU Cooling Loop Maintenance Scrub Initiation EMU Hard Upper Torso (HUT) Scrubber Deconfiguration and Install EMU Water Sample OCT2 Exam Operation Lab Dzus Fastener Repair [ABORTED] ORU Prep for Stowage ISS HAM Columbus Pass Kenwood JEM Mesh Cover Return Grille Cleaning Light Ions Detector Move 2 LSG LLC Power R&R MERLIN 1 Desiccant Swap Nitrogen/Oxygen Recharge System O2 Repress Part 1 and 2 NutrISS - ESA Nutritional Assessment Power Cycle LAB EWC Port BelAir WAP Public Affairs Office (PAO) Event in JEM Regenerative Environmental Control and Life Support System (ECLSS) Recycle Tank Drain and Fill SpaceX-25 Dragon Rendezvous Review Transfer Cygnus Cargo Operations Urine Transfer System Offload EDV Swap XROOTS Water Refill

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