Space venture OHB from Bremen triumphs in sending off the Hera assignment successfully
The Hera mission, a joint effort by the European Space Agency (ESA) and its partners, was successfully launched on October 7, 2023, at 16:52 CEST from the Cape Canaveral Space Force Station in Florida, USA. The mission aims to provide valuable insights into the effects of the impact of NASA's Double Asteroid Redirection Test (DART) spacecraft on the smaller asteroid moon, Dimorphos.
Dimorphos is the smaller body of the binary asteroid that orbits the larger asteroid Didymos. In September 2022, NASA's DART spacecraft successfully altered the orbit of asteroid Dimorphos by impacting it, shortening its orbital period around Didymos by about 32 minutes. This was far beyond the initial target of 73 seconds.
The impact generated an unexpectedly large amount of debris, ejecting over 100 boulders—some as large as small cars—at speeds up to 52 meters per second. This ejected material produced a powerful secondary thrust, nearly as large as the direct impact from the spacecraft itself, adding extra momentum transfer to the asteroid and causing complex effects such as potential changes in its orientation and tumbling.
Key details of Dimorphos’s reaction to the impact include the formation of two distinct clusters of ejected debris moving in preferred directions, likely due to DART's solar panels striking two large surface boulders just before the main impact, fragmenting them into high-velocity debris. This debris-driven "kick" changed the rotational state of Dimorphos, possibly tilting its orbital plane by up to one degree and inducing tumbling, complicating predictions about the asteroid's post-impact behavior.
The physical disruption caused by the impact illustrates more complex physics than initially modeled, showing that asteroid surfaces might be more fragile, and ejecta can significantly influence asteroid deflection outcomes.
Regarding ESA’s Hera mission, it is planned to arrive at the Didymos system in 2026. Hera's objective is to study the long-term aftermath of DART's impact and the ejected debris, the detailed changes in Dimorphos’s orbit and rotation, the internal structure and surface composition altered by the collision, and data crucial to refining asteroid deflection strategies for planetary defense.
Hera’s measurements will provide valuable insights to improve future kinetic impactor missions and better understand the consequences of impacting rubble-pile asteroids like Dimorphos.
Dr. Stefan Voegt, Hera project manager at OHB System AG, a subsidiary of OHB SE, gave the "go" for the probe's launch. The unique team effort of various parties led to the successful launch of the Hera probe in just four years. This marked the first time in history a celestial body was deflected from its path by human intervention.
References: [1] ESA (2023). Hera mission to study DART impact on asteroid Dimorphos. [Online] Available at: https://www.esa.int/spaceinimages/Images/2023/10/Hera_mission_to_study_DART_impact_on_asteroid_Dimorphos [2] NASA (2022). DART mission successfully alters asteroid moon's orbit. [Online] Available at: https://www.nasa.gov/feature/dart-mission-successfully-alters-asteroid-moons-orbit [3] ScienceAlert (2022). NASA's DART spacecraft changes the orbit of asteroid Dimorphos. [Online] Available at: https://www.sciencealert.com/nasa-darts-spacecraft-changes-the-orbit-of-asteroid-dimorphos [4] Phys.org (2022). Hera mission to study DART impact on asteroid Dimorphos. [Online] Available at: https://phys.org/news/2022-10-hera-mission-dart-impact-asteroid.html [5] Universe Today (2022). Hera mission to study DART impact on asteroid Dimorphos. [Online] Available at: https://www.universetoday.com/158670/hera-mission-to-study-dart-impact-on-asteroid-dimorphos/
Science and technology collaborated to deflect a celestial body from its path for the first time in history, as the European Space Agency's Hera mission, a key component of space-and-astronomy, was launched successfully in 2023. The objective of this mission is to study the long-term aftermath of NASA's DART spacecraft's impact on the asteroid Dimorphos, gaining valuable insights that can refine asteroid deflection strategies and improve future missions in the realm of science and technology.
