ESA’s Hera Mission on Track for Early Arrival at Didymos Asteroid System
The European Space Agency’s (ESA) Hera mission, launched on October 7, 2024, is currently halfway to its destination – the Didymos binary asteroid system. The mission is designed to study the aftermath of NASA’s DART mission, which intentionally impacted the asteroid Dimorphos in 2022, and gather crucial data on asteroid deflection techniques. This work is vital as humanity seeks to improve planetary defense capabilities.
Thanks to the spacecraft’s strong performance and careful planning by ESA’s mission control team, Hera is now expected to arrive at Didymos in November 2026 – a month earlier than originally scheduled. The early arrival allows for more time to prepare for orbital insertion and data collection.
Following its launch, Hera executed a significant engine burn to accelerate towards Mars. A successful flyby of Mars in March 2025 adjusted the spacecraft’s trajectory towards Didymos and provided an opportunity to test Hera’s instruments on a planetary body. Shortly after the Mars flyby, the team began imaging faint asteroids to calibrate the spacecraft’s main camera in preparation for observing Didymos next year.
“Hera is proving to be a flexible and dynamic spacecraft,” said Sylvain Lodiot, Head of Outer Solar System and Planetary Defence Missions Operations at ESA. “We are also benefiting greatly from the support of ESOC veterans with decades of experience flying missions to challenging destinations across the Solar System, such as Rosetta.”
Hera, the first interplanetary mission for some team members, carries a suite of instruments including the Asteroid Framing Camera (AFCA), the Thermal Infra Red Imager (TIR), the Planetary Altimeter (PALT), and the Radio Science Experiment (RSE). It also carries two CubeSat spacecraft, Milani and Juventas. The spacecraft has a mass of 1,128 kg (2,487 lb) and a dry mass of 350 kg (770 lb), with dimensions of 1.6 x 1.6 x 1.7 meters (5.2 x 5.2 x 5.6 ft).
The mission’s primary objective is to measure the size and morphology of the crater created by the DART impact, as well as the momentum transferred to the asteroid. This data will support validate the kinetic impact method as a viable strategy for deflecting near-Earth asteroids. Hera is the first mission of ESA’s Space Safety Programme, marking a significant step forward in planetary defense efforts.
The Hera mission builds upon earlier studies, including the Don Quijote concept, which involved a hyper-velocity impactor and an orbiter to measure the impact’s effects. It’s being developed in collaboration with NASA under the Asteroid Impact and Deflection Assessment (AIDA) international collaboration.
