Space and Physics
PUBLISHED
An astronomer using the early orbital predictions of near-Earth asteroids has found a shortcut to Mars, identifying a course that could allow for round-trips to the Red Planet which take under a year.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.Astronomers, including those at NASA's Near-Earth Object (NEO) Observations Program, have been scouring the skies for decades in search of potentially hazardous objects that might do significant damage to our planet. Thus far, we haven't really found any, with all known asteroids posing no threat for at least 100 years in the future, according to NASA.
That may sound like a bit of a waste of time. All those hours spent observing the sky, and not one single apocalypse-threatening asteroid we have to Bruce Willis into oblivion? Well, of course beyond planetary safety, we also learn a lot about our Solar System and the objects themselves through this constant monitoring. A new study from Marcelo de Oliveira Souza of the State University of Northern Rio de Janeiro suggests there may be another benefit to the effort: identifying shortcuts to planets we may wish to visit.
When asteroids are first detected, their orbits can be pretty uncertain. For an obvious example, asteroid 2024 YR4 caused a bit of unnecessary alarm when early observations gave it a 3.1 percent chance of impacting the Earth, before that was downgraded to close to zero. Then, it was given a 4.3 percent chance of hitting the Moon, before refinement of its orbit put that close to zero as well. The problem is that there are uncertainties in the observations. Astronomers model the orbits of the objects as they are spotted, but these orbits become much more refined with further observations, revealing its true path.
When near-Earth asteroid 2001 CA21 was first spotted, and its trajectory reconstructed, it was found to be on quite a fun journey, were space rocks sentient enough to enjoy astronomy. As well as taking it through the region Earth inhabits, it would cross Mars's path as well. Though this path has been significantly refined, Oliveira Souza found that this early work may be quite useful indeed.
"The analysis intentionally adopts this early-epoch solution because that preliminary osculating orbit exhibits a dual-node intersection geometry, in which the resulting heliocentric path intersects, or closely approaches, the heliocentric distance ranges of both Earth and Mars," Oliveira Souza explains in the paper.
Souza was interested in whether this predicted path of the asteroid could be useful as a way to design missions to the Red Planet, looking at three possible windows in 2027, 2029, and 2031. These are times when Mars is in opposition, meaning that the Earth is between the Sun and Mars, and the two planets are at their closest, occurring roughly once every 26 months.
"Among the examined alignments, only the 2031 configuration satisfies both the energetic and geometric requirements under the adopted anchoring criteria," Oliveira Souza explains. "Within that window, two complete and dynamically closed Earth–Mars–Earth architectures are identified: a 153-day rapid configuration (33 + 30 + 90 days) and a 226-day feasible configuration (56 + 35 + 135 days)."
In short, there are two potential mission trajectories, both of which would take a spacecraft to the Red Planet and back again well within a year. Whilst very cool, Oliveira Souza's main goal was to see whether early asteroid data and predicted paths could be used to guide mission design.
"[E]arly small-body orbital solutions may encode natural heliocentric geometries that help structure and highlight rapid interplanetary pathways within conventional trajectory search spaces," Oliveira Souza concludes. "The plane-anchoring approach developed here provides an innovative and generalizable framework for exploring whether similar geometric templates exist within other NEO [near-Earth object] orbital configurations."
The study is published in Acta Astronautica.
