Hera mission plans Mars flyby en route to asteroid study

Hera mission plans Mars flyby en route to asteroid study
by Erica Marchand
Paris, France (SPX) Apr 26, 2024

ESA's Hera mission, aimed at planetary defense, will utilize a Mars flyby in March next year to gain velocity as it heads towards the Didymos binary asteroid system. During this maneuver, Hera will approach Mars within 6,000 km-closer than Mars' moons' orbits-and adjust its trajectory to closely observe Mars' moon Deimos and the Martian surface itself.

The flyby details were discussed at the Hera Science Community Workshop at the ESTEC center in the Netherlands. "This swingby is part of the scheduled manoeuvres to get Hera to Didymos by the end of its two-year cruise phase," explains Michael Kueppers, ESA's Hera project scientist. He described the added velocity from Mars' gravitational pull as critical for the mission's trajectory towards Didymos.

Pablo Munoz, a Flight Dynamics engineer at ESA's European Space Operations Centre in Germany who is part of the Mission Analysis team, explained the trajectory planning: "It's truly fortunate that Mars happens to be at the right location and at the right time to give Hera a hand. This enabled us to design a trajectory that uses the gravity of Mars to push Hera towards its rendezvous with Didymos, resulting in great fuel savings for the mission. Part of the excess propellant can then be spent in advancing the arrival at the binary asteroid by a few months, thus maximising the mission's planetary defence and science return."

The mission follows NASA's DART spacecraft's successful demonstration of the kinetic impact technique for altering an asteroid's orbit in 2022. Hera will closely examine the impacted Dimorphos asteroid to gather essential data on its mass, composition, and structure.

Patrick Michel, Director of Research at CNRS at Observatoire de la Cote d'Azur in Nice and Hera's Principal Investigator, emphasized the mission's broader scientific potential: "Hera's instruments have been designed to observe Dimorphos of course, but the potential is there to turn up interesting insights about the distinctively asteroid-like Deimos as well," he noted.

The mission will also coordinate observations with other Mars missions like the Emirates Mars Mission 'Hope Probe' and possibly ESA's Mars Express and ExoMars Trace Gas Orbiter, as well as the upcoming MMX mission by Japan, which includes a rover landing on Phobos.

During the Mars swingby, Hera will use three instruments to gather data: the main Asteroid Framing Camera, the HyperScout-H for spectral analysis, and the Thermal Infrared Imager for temperature mapping.