Moon first, then Mars? Congress moves to shift space priorities.

As President Barack Obama's second term comes to an end, Congress is reconsidering the country's space priorities. The idea of a return trip to the moon is increasing in popularity. 

The Obama administration's space policy has long favored an asteroid mission by 2025 followed by a mission to Mars in the 2030s, as Ars Technica reported. But during the appropriations process, the House instructed NASA to cease the asteroid mission and instead "develop plans to return to the Moon to test capabilities that will be needed for Mars, including habitation modules, lunar prospecting, and landing and ascent vehicles," as Ars reported. The moon-before-Mars plan has seen bipartisan support in the House. 

"There is no better proving ground than the Moon for NASA to test the technologies and techniques needed to successfully meet the goal of sending humans to Mars by the mid 2030s," Rep. Mike Honda (D) of Calif., a major proponent of the new approach, told Ars. 

Prioritizing the moon over the asteroid program would represent a major shift in NASA's priorities. NASA says the asteroid mission will give them experience in human spaceflight beyond low-Earth orbit and allow them to test technologies that would be necessary in a Mars mission. NASA said a human mission to Mars could help address the question of whether life exists beyond Earth. 

"Mars is a rich destination for scientific discovery and robotic and human exploration as we expand our presence into the solar system," NASA said on its website. "Its formation and evolution are comparable to Earth, helping us learn more about our own planet's history and future." 

The administration's asteroid program has come under increased scrutiny in recent years, as it has drastically lessened in scope, with the current plan to obtain a small boulder off an asteroid's surface and return it to a location near the moon where astronauts can visit it to fulfill the president's goal, Ars reported. 

NASA asked for $66.7 million to work on the mission this year, but the House legislation would deny that request and insist on lunar exploration. The House legislation needs to go to conference with the Senate, but Ars reports it is unlikely to be challenged there. Even if vetoed by Obama, the legislation would show the next president Congress' space preferences. 

Prioritizing a return trip to the moon before the trip to Mars has gained popularity in recent years. In an op-ed for Space.com, Leroy Chiao, a former NASA astronaut and ISS commander, wrote that the Apollo program is now a distant memory and a return trip to the moon is necessary before a mission to Mars. 

"What we really need is a new generation of explorers who can handle the moon, before biting off the enormous costs and risks of sending people to Mars," he wrote. 

Dr. Chiao wrote the asteroid retrieval mission is "somewhat vague" and interest in the mission is "tepid at best." The technology that NASA would test in the asteroid mission could more easily be tested in a trip to the moon, he wrote. Once a spacecraft performs a trans-Mars injection burn, there will not be enough fuel to turn around if the hardware fails, so it is essential to make sure it works. 

"Where better to test this hardware, off-Earth, than the nearby moon (three days away)?" he wrote. "We would wring out the hardware, develop operations and train crew. Then, we would be ready to mount an astronaut mission to Mars."