Within days of splashing down in the Pacific Ocean on April 10, NASA's Artemis II crew—astronauts Reid Wiseman, Victor Glover, Christina Koch, and Canadian Space Agency astronaut Jeremy Hansen—began walking obstacle courses in spacesuits offloaded to lunar gravity, their bodies still adjusting from months in space. The data collected during those first hours, days, and weeks after landing represents something unprecedented: a detailed scientific record of how quickly human bodies can adapt to different gravitational environments and resume critical work on an alien world.
This groundbreaking research matters because future Moon and Mars missions will have no landing support personnel to assist crews. Understanding how fast astronauts can function after touching down determines how soon they can conduct vital surface operations. The Artemis II science investigations, now being processed at Johnson Space Center in Houston, will provide NASA with a blueprint for mission design and crew readiness for decades to come.
The crew underwent comprehensive health assessments within a day of splashdown as part of the Artemis II Spaceflight Standard Measures study, which collected baseline measurements of blood pressure, heart rate, eye health, and motor control. They also completed a mini obstacle course that tested real-world movements: lying down, standing up, unfurling a rope ladder, and ladder climbing. These early observations gave researchers crucial data about the body's immediate transition from microgravity to Earth's gravity.
Once back at Johnson Space Center, the work intensified. Over several days, crew members completed more obstacle courses while wearing spacesuits that were offloaded to lunar gravity—roughly one-sixth the force of Earth's gravity. Victor Glover, for instance, walked on a treadmill in a full space suit harnessed to NASA's Active Response Gravity Offload System, simulating a lunar surface walk while researchers carefully monitored how his body performed. These tests are now being analyzed to predict how crews will actually function on the Moon or Mars as they adapt to planetary gravity.
The Immune Biomarkers study took another angle, comparing blood and saliva samples collected after splashdown with preflight and in-flight samples to investigate how dormant viruses reawaken in astronauts' bodies during spaceflight. Crew members also completed cognition tests and simulated spacecraft docking tasks for the ARCHeR (Artemis Research for Crew Health & Readiness) study, while data from wrist-worn devices tracked their well-being and performance in space.
The organ chips that traveled around the Moon with the astronauts add yet another dimension to this research. Bone marrow cells from each crew member were cultured on AVATAR (A Virtual Astronaut Tissue Analog Response) chips and flew aboard Orion, experiencing the same spaceflight environment as the humans. Now being analyzed at Emulate's laboratory in Boston, these chips will help scientists understand how cells themselves respond to deep space, a molecular-level insight that could unlock new protective technologies.
Initial data collection concluded 45 days after splashdown, but medical teams will monitor the astronauts' health for life. Once processed and anonymized, the information will be available to the broader scientific community through NASA's Life Sciences Data Archive, accelerating research that could help predict crew adaptability for future missions and ultimately build the technologies that make sustained human presence on the Moon and Mars possible.