How Much Space Do Astronauts Need?

The answer could help design spacecraft for one day taking people on the months-long trip to Mars

Astronauts on ISS
NASA astronauts Scott Kelly (left) and Terry Virts (right) work on a day’s task on board the International Space Station NASA

Crewed missions to Mars have long been the purview of science fiction, but NASA keeps taking steps toward making a human colony on the Red Planet a reality. The feat demands attention to every detail, from where to land to how to deal with the boredom of the journey. It also includes calculating exactly how much space each pioneering astronaut will need during that long ride.

The Orion space capsule can carry Martian astronauts from Earth’s surface to orbit, but they’ll need a larger habitat to survive the months-long trip to the neighboring planet. That habitat’s design is still in the works, reports Sarah Fecht for Popular Science. Figuring out the optimal layout for the astronauts to live, exercise, eat and work requires taking a very close look at how astronauts already do those things on the International Space Station.

The ISS carries a crew of six people and has a habitable volume of 13,696 cubic feet, NASA reports. In more approachable terms, it’s larger than a six-bedroom house. However, any craft headed to Mars will be much more cramped, as weight will be tightly controlled because every pound needs to be propelled for the journey of around 140 million miles.

A company called Draper thinks they have the way to figure out just how much room Mars explorers will need during their trek, by putting specially designed trackers on the men and women on board the ISS.

"There's a lot that we can learn from how they're using the space station," Draper's Kevin Duda told Popular Science. "If you were to design a spacecraft to go to Mars, and you know they're going to be doing these tasks which are similar to what they're doing on the space station, you can design something that's most efficient for their time." For example, toolboxes should be easily accessible to aid repairs in any part of the habitat. 

Draper’s tracking system, originally developed for the military, uses an accelerometer to measure an astronaut’s speed, a gyroscope to measure rotation and a camera to keep the system accurate. Occasionally the first two devices can suggest movement, but the camera can verify if a person is really moving by visually tracking their surroundings.

The tests so far have sent the device on a 550-foot walk through a mock-up of the ISS. At the end of that walk at the Johnson Space Center last month, the tracking system was off by less than a yard, Fecht writes. Further tests, including runs in the microgravity of a parabolic flight, should allow the team to improve their algorithms and lessen that difference.

Testing Navigation and Tracking Technology at Johnson Space Center

Later this winter, the company plans to imitate a typical day’s work in the ISS using the Johnson Space Center’s mockup, according to a press release from Draper.

The tracking system is just one proposal on the table for NASA to consider. Eventually, the agency will chose a set-up to fly to space and use on the ISS. They still have plenty of time: NASA’s plan would not send a crewed mission to Mars until the 2030s or 2040s.

Get the latest stories in your inbox every weekday.