Bridenstine said on Thursday the space agency was still exploring what organisational changes within NASA's existing structure were "necessary to maximise efficiencies and achieve the end state of landing the first woman and the next man on the moon by 2024".
Artemis 1 would be an uncrewed mission around the moon in 2020.
"But in the coming months, we're going to put together a cadre of people that we will select from for those lunar activities".
The U.S. space agency NASA has selected Maxar Technologies as the first of its commercial partner to build a lunar outpost that will transfer astronauts to lunar surface in 2024. But the Trump administration has directed the agency to move that schedule up by four years, setting 2024 as the new target date. "We will be able to get out of the (lander), walk around on the surface of the moon, do meaningful science, leave experiments, gather rocks or regolith and then get back on the spacecraft and head back to the Gateway".
Bridenstine has said NASA's return to the moon has been thwarted not by technical reasons but because of "political risks". It will be positioned near the balance point between Earth and Moon gravity, allowing it to switch between different positions with relatively little thrust.More news: Trump appeals ruling allowing banks to hand his financial records to Congress
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There will also be five additional launches between 2022 and 2024, which will build on the three major missions and carry the building blocks of the lunar mini station.
The Gateway's power and propulsion element is a high-power, 50-kW solar electric propulsion spacecraft section that will provide astronauts access to the entire surface of the Moon.
Even if the official naming of these companies is a late action, NASA had the basis for it ever since April, when they sent out what they call 'pre-solicitations.' The first pre-solicitation disclosed NASA's plan to ask for suggestions from companies to create the ascent element on the next lunar lander.
NASA faces a huge task to hit the 2024 target. Bridenstine admitted in March that "SLS is struggling to meet its schedule", and the agency has no lunar lander; only last week did it select 11 space technology firms to study various lander elements.