Asteroid-inspired trajectory could cut Mars round trip to months, study suggests

A researcher has outlined a potential shortcut to Mars that could compress a round trip to a matter of months rather than years—if spacecraft can one day fly fast enough to use it. In a study published in Acta Astronautica, Marcelo de Oliveira Souza, a cosmologist at the State University of Northern Rio de Janeiro, analyzed the early predicted trajectory of a near-Earth asteroid that crosses the orbits of both Earth and Mars.

By tracing the initial route of asteroid 2001 CA21 around the sun, he concluded a human-made spacecraft might follow a similar path on a more direct transfer between the planets. Today’s Mars missions are bound by orbital mechanics. On average, Mars sits about 140 million miles from Earth, but the distance varies widely as both worlds circle the sun.

The most favorable launch opportunities arrive about every 26 months, when the planets align on the same side of the sun. Even then, the journey typically takes seven to 10 months, and a crewed expedition would likely wait for another window to return—stretching a mission to nearly three years, according to NASA.

Souza’s modeling points to 2031 as a particularly promising year for a shorter trip. He identified two potential round-trip profiles with total durations of roughly 153 and 226 days. However, he emphasized that either option would demand spacecraft speeds—and landing capabilities—well beyond what current rockets and systems can achieve.

The concept remains largely theoretical but, he argues, could inform how agencies plan future Mars trajectories. The work arrives as NASA is stepping up plans for human exploration beyond the moon. A key objective of the agency’s Artemis program is to use a series of crewed lunar landings to refine technologies and operations for deeper-space travel, including eventual missions to Mars.

In the nearer term, NASA plans in 2028 to launch what it describes as the first nuclear-powered spacecraft to Mars. The Space Reactor-1 vehicle is expected to reach the planet in 2030 and deploy three helicopters similar to the retired Ingenuity aircraft to scout for potential human landing sites and use radar to search for underground water.

For now, the asteroid-inspired route is a provocative addition to mission design playbooks—one that depends on breakthroughs in propulsion and entry, descent and landing. As agencies chart possible timelines for the first human journeys to the red planet, studies like Souza’s lay out what might be possible when technology catches up.