SpaceX CEO Elon Musk welcomed the launching of Space Force, the newest US military service, with a “Star Trek”-themed tweet: “Starfleet begins.”

On Friday, President Donald Trump signed the National Defense Authorization Act (NDAA) a $$738 billion bipartisan defense spending bill.

Part of the NDAA authorizes the Space Force as a military service under the Department of the Air Force. It is the first military service introduced since the US Air Force spun off from the US Army in 1947. Trump first floated a Space Force initiative in March 2018 speech. (A similar bipartisan proposal for a Space Corps was introduced in the House in 2017 was cut from a previous NDAA.)