When humanity finally sets foot on Mars, the astronauts won't just be thanking the engineers who built the rockets; they will be thanking Susan Schuh for the fact that they can sleep, eat, and stay sane during the nine-month journey. As the lead of NASA’s Flight Crew Integration Operational Habitability (OpsHab) team, Schuh is the guardian of the "human factor" in the most hostile environment known to man.

Based at the Johnson Space Center in Houston, Schuh manages a unique and critical asset: the Crew Comments Database. This repository contains over 115,000 debrief comments from astronauts who have lived on the International Space Station (ISS) over the last 25 years. It is a catalogue of grievances, triumphs, and mundane details that are shaping the design of the Artemis moon base and the Mars transit vehicle.

The "Small" Things That Matter

"Spaceflight is glamorous in the movies, but in reality, it is about survival," Schuh explains. Her work focuses on the friction points of life in zero-g. How do you design a sleeping bag that doesn't feel like a coffin? How do you organize 10,000 items of inventory so a crew member doesn't spend 4 hours looking for a wrench? These "habitability" issues, if ignored, can lead to crew fatigue and mission failure.

• The Data of Comfort: Schuh’s team analyzes feedback on everything from the noise levels of ventilation fans to the texture of space food. "We learned that crew members need a 'private' visual space," she notes. "Just seeing a photo of Earth or a plant can lower cortisol levels significantly."
• From Chernobyl to Houston: Schuh’s journey to NASA began with a study on the psychological effects of the Chernobyl nuclear disaster. This sparked her interest in how humans function in extreme, high-stress environments. After an internship in 2000, she dedicated her career to "supporting the humans in human spaceflight."

Designing for Mars

The stakes are rising. On the ISS, if a toilet breaks, replacement parts can be sent on the next cargo ship. On a mission to Mars, there is no resupply. Schuh’s team is currently using the ISS as a testbed for "Mars-class" logistics, simulating the autonomy crews will need when communication delays with Earth reach 20 minutes.

"The Crew Comments Database is my pride and joy," Schuh says. It ensures that the mistakes of the past—like the cramped quarters of the early Shuttle era—are not repeated. As NASA prepares to launch Artemis II, Susan Schuh’s invisible hand will be there, ensuring that the Orion capsule feels a little bit more like home.