President Donald Trump has signed into law a bill that adds exploration of Mars as a NASA goal.

The new law also authorizes $19.5 billion in space agency funding for the 2017 budget year, which began Oct. 1. Trump recently sent Congress a budget proposal that authorizes $19.1 billion for the space agency next year.

The measure amends current law to add human exploration of Mars as one of NASA's objectives. It also directs NASA to manage human space flight programs to help humans explore Mars and other destinations.

Trump signed the bill Tuesday in the Oval Office surrounded by astronauts and bill sponsors, including Sens. Ted Cruz, R-Texas, and Marco Rubio, R-Fla.

Both senators challenged Trump during the presidential campaign.