NASA's leaders say an overly aggressive timeline from the Trump administration and a legal fight over a contract are two reasons why it's altering plans for the Artemis lunar program.

NASA is counting down to what should be the final major test of the massive rocket it is building to put the first woman and the next man on the moon.

The two countries' space agencies say the proposal, which sets no time frame, could include an orbiting station, a base on the surface, or both.