Martian Spacesuits Must Be 40% Lighter Than Lunar Models

Current advanced spacesuits being developed for lunar missions are too heavy for effective use on Mars, according to a presentation by NASA and industry engineers. The Exploration Extravehicular Mobility Unit (xEMU), designed for the Artemis program, weighs approximately 170 kg (376 lbs). While manageable on the Moon's one-sixth gravity, where it would feel like 28 kg (61 lbs), the same suit would impose a substantial 64 kg (141 lbs) burden on an astronaut in Mars' three-eighths gravity.

To determine a suitable weight for a Martian suit, engineers established a baseline astronaut weight of 50 kg (108 lbs) and considered a reduced aerobic capacity due to the long transit to Mars. Accounting for the internal pressure of the suit, which offsets some perceived weight, the maximum acceptable mass for a Martian Exploration Extravehicular Mobility Unit (MxEMU) was calculated to be 104 kg (229 lbs). This represents a critical 40% reduction from the current xEMU design.

The need for this lighter suit is underscored by scenarios like a "walkback" to a habitat if a rover malfunctions. The energy expenditure and oxygen consumption associated with carrying a heavy suit limit an astronaut's operational radius. Even with the proposed weight reduction, a safe walkback distance is estimated at only 1.8 km (1.1 miles) at a typical walking speed.

Achieving this 40% weight cut requires significant design changes. Engineers suggest re-evaluating the current suit's modularity, which contributes heavily to its mass. A potential solution involves returning to a more integrated design philosophy, similar to the Apollo-era suits, where components served multiple structural and functional roles to save weight. This approach, however, necessitates trade-offs in safety, as older designs were less tolerant of single system failures compared to modern multi-fault tolerant suits.