ALT CHAPEA mission 2 commander Ross Elder in protective suit collecting geological samples inside a controlled sandy environment during a simulated extravehicular activity. (c) NASA

ALT CHAPEA crew member James Spicer seated with arm extended for blood draw, Matthew Montgomery standing nearby to perform blood collections to monitor their health. (c) NASA

ALT CHAPEA mission 2 medical officer Ellen Ellis wearing a protective helmet and gloves holding a small blue and white object against a textured reddish rock background. She collects samples during an extravehicular activity. (c) NASA

ALT Four individuals in NASA flight suits stand with arms crossed inside a spacecraft module near a door labeled 'TO SURFACE'. Members of NASA’s CHAPEA (Crew Health and Performance Exploration Analog) mission in NASA flight suits pose for a group photo inside their habitat. (From left to right: Ellen Ellis, Ross Elder, James Spicer, and Matthew Montgomery) (c) NASA

ALT Golden astronaut figurines mounted on black bases labeled 'EXPLORE' for the 1st Explore Analog Mission, lined up on a reflective surface.

ALT Explore1 group photo with students, teachers and Explore project partners inside the Alqueva Mars habitat in Portugal