Asteroid Updates: Hera Mission, NASA’s DART & Planetary Defense

The European Space Agency’s (ESA) Hera spacecraft has completed its largest maneuver to date, placing it firmly on course for a November 2026 rendezvous with the Didymos binary asteroid system, according to ESA officials.

The maneuver, executed on March 22, 2026, involved firing Hera’s chemical thruster for approximately five minutes, altering the spacecraft’s velocity by 377 meters per second. This course correction is critical for achieving a stable orbit around Didymos, a near-Earth asteroid system consisting of the main asteroid Didymos and its smaller moon, Dimorphos.

Hera’s mission is to conduct a detailed post-impact analysis of Dimorphos, which was intentionally collided with by NASA’s Double Asteroid Redirection Test (DART) spacecraft in September 2022. The DART mission successfully altered Dimorphos’ orbit, demonstrating the feasibility of using kinetic impact as a method of asteroid deflection. Hera will measure the crater formed by the impact, assess the momentum transfer, and characterize the physical properties of both asteroids.

The mission aims to validate the kinetic impact technique as a viable planetary defense strategy. Data gathered by Hera will be crucial for refining models and predicting the effectiveness of future asteroid deflection efforts. The spacecraft carries a suite of instruments, including the Asteroid Framing Camera (AFCA), the Thermal Infra Red Imager (TIRI), and the Planetary Altimeter (PALT), to achieve these objectives.

Launched on October 7, 2024, aboard a SpaceX Falcon 9 rocket from Cape Canaveral, Hera too deployed two CubeSats, Milani and Juventas, which will conduct their own independent investigations of Didymos and Dimorphos. Juventas is designed to attempt a landing on Dimorphos, a first for planetary defense missions.

Interestingly, NASA inadvertently altered the orbit of Dimorphos more than initially anticipated. Even as the DART mission successfully demonstrated the kinetic impactor technique, the change in Dimorphos’ orbital period was greater than predicted, prompting further study by Hera. The precise measurement of the impact’s effects is a key goal of the mission.

Hera represents the first mission of ESA’s Space Safety Programme and is a collaborative effort with NASA under the AIDA (Asteroid Impact & Deflection Assessment) international collaboration. Orbital insertion around Didymos is currently scheduled for November 2026, with scientific observations expected to continue for approximately two years and nine months.