Why is NASA sending its astronauts to the bottom of the ocean?

To train for future missions to Mars, NASA is sending a group of scientists, engineers, and astronauts to the bottom of the ocean.

Pictured at the end of Mission Day 1 are the NEEMO 21 aquanauts, clockwise from top: Matthias Maurer (ESA), Marc O Griofa (Teloregen/VEGA/AirDocs), NASA astronaut Megan McArthur, NASA astronaut Reid Wiseman, Dawn Kernagis (Institute for Human & Machine Cognition), and Noel Du Toit (Naval Postgraduate School). Inside the Aquarius habitat are Florida International University Habitat Technicians Hank Stark (left) and Sean Moore (right).

Karl Shreeves/NASA

July 26, 2016

To prepare for space, astronauts are heading to the other final frontier: the ocean floor.

On Thursday, NASA sent a team of astronauts and scientists more than 60 feet below sea level for a 16-day underwater expedition. NASA Extreme Environment Mission Operations 21, or NEEMO, is designed to simulate scenarios that may arise in future Mars missions.

“Equipment can fail, communication can be challenging, and tasks can take longer than expected. Other tasks go just as planned. All cases are equally beneficial,” NEEMO Project Lead Bill Todd said in a statement. “It’s how we learn and how we are able to assemble all of this together so that someday we’re prepared for the unexpected when we are living on and traversing the Martian surface.”

In Aquarius, NASA’s undersea habitat, the NEEMO crew will live in spacecraft-like conditions while testing new software and technologies, such as a mini-DNA sequencer. On simulated spacewalks, astronauts will collect biological and geological samples. The mission will report back to NASA regularly, in preparation for deep-space communication delays.

The first half of the NEEMO mission will be led by NASA astronaut Reid Wiseman, an ISS veteran who was a naval aviator and test pilot before joining the agency. The second half of the expedition will be led by NASA astronaut Megan McArthur, a PhD oceanographer who was also involved in the 2009 STS-125 shuttle mission.

NASA has set its sights on the red planet in recent months, announcing plans to send a crewed mission to Mars sometime in the 2030s. In July, the agency commissioned five domestic aerospace companies to design new Mars orbiters.

“We’re excited to continue planning for the next decade of Mars exploration,” said Geoffrey Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington, in a NASA press release.

In the meantime, NASA is preparing for the 2020 launch of a new Mars rover. The successor to Curiosity will hunt for signs of ancient Martian life, meanwhile laying the groundwork for future human exploration. Among other technologies, the rover will test a device that converts CO2 to pure oxygen.

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But there may be one snag for future Mars missions: a shoestring budget. NASA’s budget for the new Rover was $1 billion less than its predecessor, The Christian Science Monitor reported in May.