For decades, Mars has been a centerpiece of the United States’ space exploration agenda. But a dramatic shift is taking place.

As the Trump administration has slashed science spending and as NASA’s Artemis moon program has taken priority, the future of Mars exploration has become a question mark.

In budget proposals, the White House has suggested canceling some existing and future red planet missions. Elon Musk, one of the most vocal champions of the need to “occupy Mars,” announced recently that SpaceX is concentrating first on “building a self-growing city on the Moon.”

Taken together, these changes could leave Mars — located more than 140 million miles from Earth — even farther out of America’s reach.