Souza finds 153-day Mars route from asteroid data
Marcelo de Oliveira Souza has found a way to cut a mars round trip to 153 days. The researcher at the State University of Northern Rio de Janeiro used early asteroid orbit data to test faster Earth-Mars paths.
The study, published in Acta Astronautica, says hundreds of days could come off a return mission. It also lays out complete 2031 Earth-Mars-Earth profiles with a 33-day outbound leg and a 90-day return, or a 56-day outbound leg and a 135-day return.
2001 CA21 and five degrees
Souza built the analysis around asteroid 2001 CA21 because its early predicted path crossed both Earth and Mars. He searched for routes that stayed within five degrees of the asteroid’s tilt, which is a narrow enough band to make the geometry useful as a screening filter rather than a broad wish list.
That approach matters for mission planners because it looks for transfer opportunities before the orbit is fully pinned down. The paper says future missions do not have to follow 2001 CA21 itself, which turns the asteroid into a test case instead of a destination.
2031 wins the alignment test
Souza tested Mars oppositions in 2027, 2029, and 2031. The analysis found that 2031 was the only year when the Earth-Mars geometry lined up favorably with the asteroid’s orbital plane.
He wrote, "The 2031 Mars opposition supports two complete sub-year round-trip missions consistent with the CA21-anchored plane, illustrating how early small-body orbital data may contribute to the early identification of rapid interplanetary transfer opportunities." The paper also says, "This study illustrates how the well-defined plane geometry of a preliminary small-body orbit can be employed as a methodological screening tool for rapid interplanetary transfer identification."
What planners get next
Mars opposition comes roughly every 26 months, so the 2031 case is one specific window inside a recurring cycle. For planners, the practical change is not a fixed mission date but a narrower set of routes worth checking before they spend time and fuel on slower options.
The unresolved piece is whether this screening method is ready for actual mission design outside the 2031 geometry. The study says the shortcut logic can be applied beyond 2001 CA21, but it does not turn that into a launch plan.
