Overview
- An Acta Astronautica paper identifies two fast Earth–Mars–Earth mission plans, one at roughly 153 days and another at about 226 days, by constraining routes to the early orbital plane of asteroid 2001 CA21.
- The method treats the asteroid’s preliminary orbit as a geometric guide and finds that only the 2031 Mars opposition yields closed round trips under a five-degree plane constraint.
- One option totals 226 days with a 56‑day trip to Mars, a 35‑day stay, and a 135‑day return, while the shorter 153‑day profile is labeled extreme due to far higher energy demands.
- The fast transfers call for departure speeds that leave Earth with about 16.9 km/s of extra velocity, with Mars arrival near 16.6 km/s and Earth reentry near 15.1 km/s, which outruns chemical rockets and strains heat-shield materials.
- The study provides trajectories only, with no vehicle mass or entry design, and it points to next steps such as surveying other asteroid-based templates and advancing European nuclear thermal work led by CEA with ArianeGroup and Framatome toward a mid‑2030s demonstrator.