Why Not Use the Space Station as a Mars Mission Simulator?

The ISS4Mars project would help astronauts get ready to venture farther from home.

Some day the planet outside the window will be red. Might as well start practicing now.

You’ve read about those long-duration simulations, where adventurers inside sealed habitats pretend to be on a voyage to Mars? A group of Italian researchers wants to turn the realism up a notch.

They propose using part of the International Space Station as a dedicated facility for Mars mission simulation. Initiated by a group of advanced planners from the Italian Space Agency and Thales Alenia Space, the project— called ISS4Mars— would have part of the crew living and working in isolation from the rest of the station’s activities for at least some of their time in orbit.

The astronauts would still exercise and perform experiments, but they’d be confined to certain space station modules. Their communications with the ground would incorporate an (artificial) multi-minute time delay, just as a Mars crew would experience. That simple switch would push them to operate more autonomously than space crews do today, since they couldn’t confer with Mission Control as easily. The time delay could be lifted in case of emergency.

“[This will] not be a collection of individual experiments, but a fully-fledged simulation where all the gathered knowledge will come together for the first complete simulated Mars voyage,” said Cesare Lobascio, a space infrastructure systems lead at Thales. The advantage of such an exercise, he added, is that, in the event something went wrong, the astronauts could break simulation and return home safely within hours. That won’t be an option on a Mars expedition.

Mars-bound astronauts are likely to follow different schedules than do the crews in Earth orbit. For example, while station astronauts typically exercise for two hours a day to fight the debilitating effects of microgravity, they may need more treadmill time on a Mars mission. Station astronauts typically have some difficulty walking when they re-enter normal gravity after long missions. On Mars, where the gravity is one third that of Earth, they’d likely have to start working immediately upon arrival.

The ISS4Mars concept is being reviewed by the international station partners for possible inclusion late in the orbiting lab’s lifetime. It was first proposed at a meeting of the International Space Exploration Coordination Group, and was discussed further at the International Astronautical Conference in Australia in September. The space station is expected to operate in its current form until 2024, and ISS4Mars would start no earlier than 2022. There are other ideas for when and where to simulate Mars missions, however, and NASA hasn’t said whether it’s behind this particular concept.

ISS4Mars proponents suggest using the station’s Tranquility node as the hub for a simulated Mars mission, along with some of the connecting modules. These could include the cupola, a storage space called the Permanent Multipurpose Module (PMM), or the Bigelow Expandable Airlock Module that is testing an inflatable structure in space. While not all of these segments are connected to each other, Thales is open to modifying the modules for a simulated Mars mission. The company built several of the ISS modules, representing more than half the station’s overall habitable volume.

For now, it’s just an idea. “We are at a rather conceptual stage at the moment, with basic needs defined and a first proposal on a possible architecture utilizing the key ISS elements around [Tranquility],” Lobascio said, emphasizing that more study is needed. Key questions include how to simulate the time delay, and whether other modules would need to be relocated for the Mars simulation.