The International Space Station is facing a $1 billion budget shortfall – separate from President Donald Trump's plans to further cut funding – that will require dropping the number of NASA astronauts on the orbiting platform.

The release of NASA's latest budget reveals the Orion spacecraft and Lunar Gateway space station are getting the chop. The US$18.8-billion total figure decreases spending by $6 billion, or 24%, as the space agency increases funding for crewed Moon and Mars missions.

U.S. President Donald Trump's administration is seeking to axe key parts of NASA's moon program in favour of commercial alternatives and his Mars-focused agenda. It also proposes cuts to Gateway, a lunar space station in which Canada has already invested.