NASA is planning a year-long manned mission to orbit the Moon in 2027 as a part of its preparations to send humans to Mars in the 2030s.
The US space agency is building a "deep-space gateway" around the Moon to test for operations and technology required for NASA's journey to the red planet.
Eventually, the lunar presence would also serve as a launching point for the spacecraft that will carry humans to Mars, said Greg Williams, deputy associate administrator for policy and plans at NASA's Human Exploration and Operations Mission Directorate.
Williams provided a detailed look at the first two phases of NASA's current plan to send humans to Mars at the Humans to Mars Summit in Washington DC.
The year-long lunar mission will be preceded by at least five missions - four of them crewed - which will deliver hardware such as a crew habitat, Williams said.
The last piece of delivered hardware would be the Deep Space Transport vehicle that would later be used to carry a crew to Mars, he said.
"If we could conduct a yearlong crewed mission on this Deep Space Transport in cislunar space, we believe we will know enough that we could then send this thing, crewed, on a 1,000-day mission to the Mars system and back," Williams was quoted as saying by the 'Space.com'.
Currently, the lunar stages of the plan to get humans to Mars rely heavily on NASA's Space Launch System (SLS) rocket to send the necessary payloads and crews to cislunar space - the region between Earth and the Moon.