The schedule didn't provide additional details about the event or the document, but a White House official later confirmed that the directive is linked to human space exploration policy.
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Harrison Schmitt, the most recent living human to walk on Earth's satellite, was present at the signing, which happened 45 years to the minute after he landed on the Moon. Yesterday, he signed Space Policy Directive 1, calling for a United States-led program with private sector partners to do just that, and then send humans to Mars.
Trump's plans, which are a part of the Space Policy Directive 1, intend to prioritise the exploration of space, something he has been stressing on for a while now.
'We will establish a foundation for an eventual mission to Mars, and perhaps someday, to many worlds beyond'.
NASA says work toward the new directive will be reflected in NASA's 2019 budget.
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Technology website Ars Technica noted that under a status quo situation, "it is hard to see NASA or its partner astronauts landing on the moon before 2030, presuming the next president sticks with this plan".
"Today, the same spirit beckons us to begin new journeys of exploration and discovery, to lift our eyes all of the way up to the heavens and once again imagine the possibilities waiting in those big, handsome stars if we dare to dream big and that's what our country is doing again", he said.
Lunar sample 70215 was retrieved from the Moon's surface and returned by Mr Schmitt's Apollo 17 crew.
Trump's announcement essentially revives goals that former President George W. Bush announced in 2004.
"Imagine the possibilities waiting in those big, lovely stars if we dare to dream big, and that's what our country is doing again".
Neil Armstrong became the first man to walk on the Moon - on July 20, 1969.
Under the directive, the US Government is also expected to work closely with other nations and private industry.