A report mandated by Congress found that NASA's goal to get humans to Mars in 2033 is probably not possible.

Instead, NASA should realistically aim for 2037, according to a recent report from the Institute for Defense Analysis's Science and Technology Policy Institute.

"Our analysis suggests that a Mars orbital mission could be carried out no earlier than the 2037 orbital window without accepting large technology development, schedule delay, cost overrun, and budget shortfall risks," it said.

NASA Administrator Jim Bridenstine told Congress earlier this month that the agency's accelerated plans to get humans back to the moon will also help it get people to Mars.

"We can move up the Mars landing by moving up the moon landing [to 2024]," Bridenstine told the House Committee on Science, Space and Technology. "We need to learn how to live and work in another world. The moon is the best place to prove those capabilities and technologies. The sooner we can achieve that objective, the sooner we can move on to Mars."

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Bridenstine promised lawmakers that he would present to them an amended fiscal 2020 budget to include more funding for the moon mission this month. The report, which was completed before the lunar mission's announcement , uses the original 2028 goal of getting back to the moon.

A trip to the moon will be easier – and cheaper – than the mission to Mars. Mars is at least 33 million miles from Earth depending on orbits, while the moon is about 239,000 miles away.

The report estimated that it would cost $120.6 billion to go to Mars in 2037.

Rep. Ed Perlmutter, D-Colo., said at a hearing this month that he was "really disappointed" about the report's conclusion but added that NASA's plan to move up the lunar landing could also move up the timeline for the Mars mission.

But some are still questioning the feasibility of a 2024 mission to the moon.