President Donald Trump's NASA budget request for the 2020 fiscal year includes funding for a Mars sample return mission that could launch as soon as 2026, the space agency's chief Jim Bridenstine said today (March 11).

The mission would fetch rock samples packed up by the agency's Mars 2020 rover and bring them back to Earth for study in terrestrial labs. Such a mission has frequently been discussed, but not typically included on a budget request for the agency; NASA's concrete timeline for Mars science missions to Mars has always fizzled out after the Mars 2020 rover mission.

This year's budget request was billed as "Moon to Mars" and highlights components necessary for human space exploration, first in the context of the moon and then of Mars. "The moon is the proving ground; Mars is the horizon goal, and it requires an all-of-the-above approach," Bridenstine said during a news conference held today to unveil the budget request.

According to the budget proposal, NASA aims to spend $109 million in 2020 on "future Mars activities," much of that centered on early development work on a sample-return project, NASA's Deputy Chief Financial Officer Andrew Hunter told reporters in a teleconference today. That funding level would increase by hundreds of millions of dollars in subsequent years to continue the mission's development, he added.

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The agency has yet to release many details about the Mars sample return mission, which is nestled within a $2.6 billion budget request for planetary science as a whole for fiscal year 2020, which begins in October 2019 and listed to potentially launch by 2026. (Mars mission launches are typically timed to match the point when the planets are closest together, so missing this window would likely cause a two-year delay .) The budget documents released so far do not include breakdowns for individual missions.

The budget also fully funds the Mars 2020 mission , Bridenstine said during the news conference. That mission is scheduled to launch in the summer of 2020 and land Feb. 18, 2021. It includes not just the sample-caching rover, but also a helicopter designed to navigate Mars' thin atmosphere.

That mission is easier to design than a sample-return mission , which must lift off Mars despite the planet's strong gravity and navigate back to Earth. No space agency has yet accomplished that feat at a planet — only at the moon and smaller bodies.

The president's budget request does not represent the funding NASA will actually receive; final appropriation amounts are determined by Congress.