Members of the House Committee on Science, Space, and Technology repeatedly questioned the feasibility of NASA's strategy to get to the Red Planet by the 2030s at a special hearing today. Representatives cited financial concerns and some even suggested that NASA's efforts should be redirected toward cleaning up space debris and protecting Earth from possible asteroid impacts.

The chief concern was cost, since the entire mission could require over a trillion dollars. Much of the money will be spent to develop new technologies — like a system to protect astronauts from space radiation — that are needed to ensure deep-space travel is even possible. Rep. Dana Rohrabacher (R-CA) and others said that the money might be better spent for other space projects, like cleaning up the space debris surrounding Earth, and creating a system to protect our planet in case of a potential asteroid impact. "There are a lot of things we could be doing in space," Rohrabacher said. "I hope that we make sure that we don’t waste dollars on things that we don’t accomplish anything with."

"I hope that we make sure that we don’t waste dollars on things that we don’t accomplish anything with."

Rep. Jim Bridenstine (R-OK) talked about the 2014 National Research Council report, which was mandated by Congress and concluded that NASA's current strategy won't accomplish sending humans to Mars. Bridenstine questioned whether NASA's strategy improved at all. "We need to make sure that Congress is aware and understands what the objective here is and ultimately the direction we’re going to go," Bridenstine said, "because I don’t want to get another report in 10 years that says, under no circumstances will we ever get to Mars and between now and 10 years from now we will have made all these investments believing one thing and being told later something else."

The hearing was meant to discuss NASA's efforts to build a habitat for astronauts on their way to Mars. It comes five months after Congress granted NASA $19.3 billion in its latest spending bill. A report attached to the bill also ordered the space agency to spend at least $55 million to develop a deep-space habitat module and to have a prototype completed by 2018.

NASA plans to transport astronauts to Mars with a rocket called the Space Launch System (SLS) and a crew capsule called Orion. The space agency is currently building both; a test flight for the whole system is scheduled for 2018. But if NASA is serious about deep-space exploration, the agency has to develop a craft that can give astronauts enough space to live relatively comfortably during the months-long journey to the Red Planet.

NASA needs to develop habitat modules if it's serious about deep-space exploration

These habitats will also have to provide clean air, water recovery systems, and on-board medical services, as well as areas for the astronauts to exercise and make food. Most important, the habitat modules will have to protect humans from space radiation. Jason Cursan, the director of the human exploration and operations mission directorate at NASA, said that space radiation and cosmic rays, which increase the risk of getting cancer for astronauts, represent challenges that NASA still doesn't know how to fully solve. "There isn’t any current technology to adjust the high energy of [cosmic galactic rays]," Cursan said.

Despite that, Cursan reassured the members of Congress at the meeting that, along with its commercial partners, NASA will be able to achieve a prototype of a deep-space habitat by the 2018 deadline. The habitat will most likely consist of not just one big part, but multiple parts that will be assembled in space, first in a test flight around the Moon in the 2020s, Cursan said. That will allow NASA manage the space station in case of emergency, like a fire or depressurization event.

To meet the 2018 deadline, NASA announced last month that it was seeking proposals for the development of habitat prototypes from private companies, as well as US universities and nonprofits. The winning concepts will be announced in August. In March 2015, NASA had already awarded up to $1 million to seven companies — including Boeing, Lockheed Martin, Bigelow Aerospace, and Orbital ATK — to study and develop habitats.

The prototype of a deep-space habitat will be completed by the 2018 deadline, Cursan said

This is not the first time that NASA’s Mars mission was criticized in Congress. In February, witnesses said that NASA was in need of a much clearer plan to reach the Red Planet. Just like in that hearing, some witnesses today criticized the NASA's Asteroid Redirect Mission (ARM) and questioned its function in the larger mission of sending humans to Mars. ARM will send a robotic spacecraft to capture a small piece of an asteroid and bring it into lunar orbit, where humans on the SLS can visit it. Many planetary experts have claimed ARM won't advance scientific knowledge that much. But NASA says ARM's main goal is to test new solar electric propulsion technology that the agency says will be necessary to reach the Red Planet. At the hearing, Cursan repeated that position.

"That’s the experience we will need to send cargo into Mars and eventually our crew into Mars as well," Cursan said, adding that it "could be interpreted as an essential part of going to Mars."