On September 15, 2020, the first major industrial contract for Hera - ESA's new planetary defense/asteroid exploration mission - was officially signed at the ESA/ESOC (European Space Operations Centre) in Darmstadt (Germany). The 130 Mio EUR industrial contract (Hera overall budget: 300 Mio EUR) was signed with OHB System AG and includes the detailed design, manufacturing and testing of Hera. Delegations from ESA member states were present at the signing during a (semi-virtual) seminar dedicated to the project.
Hera – named after the Greek goddess of marriage – will be humankind’s first probe to rendezvous with a binary asteroid system, a little understood class making up around 15% of all known asteroids.
HERA is Europe’s contribution to AIDA (Asteroid Impact & Deflection Assessment), an international global defense collaboration between European and American scientists. NASA's DART (Double Asteroid Redirect Test) spacecraft, scheduled to launch in July 2021, will perform a kinetic impact on the smaller of the two asteroids. Hera will follow up with a detailed post-impact study to transform this large-scale experiment into a controlled and reproducible asteroid deflection technique.
In doing so, Hera - a desk-sized probe - will demonstrate several innovative technologies, including autonomous navigation around an asteroid (like autonomous cars on Earth), while collecting scientific data crucial to our understanding of the history of our Solar System, in particular the collision process that is at the heart of the formation of planets. This data will also help scientists and future mission designers to better understand the structures and compositions of asteroids, thereby optimising the design of instruments dedicated to interacting with them, whether to collect samples, exploit their resources or deflect them.
Hera will also deploy Europe's first deep-space CubeSats (miniature satellites made from 10-cm boxes) to study the asteroid closely, including the first-ever radar sounding of the interior of an asteroid using an enhanced version of the on-board radar system on ESA's Rosetta comet study mission.
First mission to a two-asteroid system
Scheduled for launch in October 2024, Hera will travel to a two-asteroid system, a pair of near-Earth asteroids called Didymos. The main celestial body is an asteroid the size of a mountain (780m in diametre), around which orbits a small moon of 160 metres, roughly similar in size to the Great Pyramid of Giza. This one was officially named "Dimorphos" in June 2020.
DART's kinetic impact on Dimorphos in September 2022 is expected to modify its orbit around Didymos and create a substantial crater. This small moon will become the first celestial body whose orbital trajectory and physical characteristics have been deliberately altered as a result of human intervention. Hera will arrive in the vicinity of the Didymos system at the end of 2026 and will study it closely for at least six months.
The signing of this contract covers the entire development, integration and testing of Hera, including its sophisticated guidance, navigation and control (GNC) system. The contracts for the two CubeSats hosted on Hera and the related technological developments are already underway.
Hera's European partners
The contract was awarded to a consortium led in Bremen (Germany) by the prime contractor OHB System AG. Among the seventeen ESA Member States contributing to the HERA mission, Germany is at the forefront. Germany is responsible for the complete design and integration of Hera, its main navigation cameras, tanks, thrusters, high-gain antenna, reaction wheels and mass storage unit.
Italy is working on the mission's power supply subsystems, deep space transponder, propulsion subsystems and solar panels, as well as the CubeSat mining exploration system. It is also contributing to the on-board radio science experiment on Hera and the two CubeSats.
Belgium is developing Hera's on-board computer and software, the brains of the spacecraft, as well as its power conditioning and distribution unit, the heart of its electrical subsystem. It is also contributing to the Hera thermal imager (developed by Japan) and the CubeSats Operations Center at ESA/ESEC.
France is providing the Juventas low-frequency radar and star trackers, and supports the planning of CubeSats payload operations and close proximity trajectories. It is also heavily involved in the mission's scientific operations. French researchers Benoît Carry (Observatoire de la Côte d'Azur), Sébastien Charnoz (Institut de Physique du Globe de Paris), Alain Hérique (Institut de Planétologie et d'Astrophysique de Grenoble), Naomi Murdoch (ISAE-SUPAERO) and Jean-Baptiste Vincent (DLR Institute of Planetary Research) are part of Hera's international investigation team, which is coordinated by Patrick Michel, research director at the CNRS.
Luxembourg leads the CubeSat "Juventas" which embarks the radar and the inter-satellite communication system that will allow Hera's two CubeSats to communicate with Earth through an innovative network that will use Hera as a data relay.