The Hera mission, part of the European Space Agency's (ESA) planetary defense program, is set to launch between October 7 and 27, 2024, from Cape Canaveral on a SpaceX Falcon 9 rocket. Hera will study the aftermath of NASA's 2022 DART mission, which successfully altered the trajectory of an asteroid through a direct impact.

By closely examining the effects of DART's impact, Hera aims to refine asteroid deflection strategies for future planetary defense initiatives.

Oliver Grassmann, Executive Vice President Satellites at Beyond Gravity, said, "Changing an asteroid's trajectory is an important planetary defense technique for humanity if a large asteroid is ever found to be on a collision course with Earth. We provided important components to this mission. Our solar wings make sure that Hera always receives enough electrical power for its operations, and our central tube acts as the backbone of the spacecraft." The German satellite manufacturer OHB in Bremen is the prime contractor for the Hera mission.

Solar wings for Hera
The Hera spacecraft, which is about the size of a van, is equipped with two solar wings provided by Beyond Gravity. These 5-meter-long wings consist of three hinged panels each, resulting in a total surface area of approximately 14 square meters. This marks the first time Beyond Gravity has developed complete solar arrays for a European mission. The company's mechanisms ensure that the solar arrays are always optimally aligned with the Sun.

The solar arrays are designed to operate in extreme conditions, functioning at temperatures between -100 C and +140 C. Even when Hera is beyond Mars, where sunlight is only 17% as strong as near Earth, the solar panels will generate around 800 watts-sufficient to power key systems like the onboard computer, navigational cameras, and communication systems.

Structural backbone
Beyond Gravity also supplied the central structure of the Hera spacecraft, made from carbon fiber reinforced polymer. This tube serves as the main structural element, comparable to the chassis of a car. It holds all the spacecraft components together and plays a crucial role in connecting Hera to its launcher during launch. The tube houses the propellant tanks, thrusters, and equipment decks, ensuring the spacecraft remains structurally sound throughout its journey.

Hera is set to follow up on NASA's DART mission, which impacted the asteroid Dimorphos in September 2022, marking the first successful planetary defense demonstration. After its launch in October 2024, Hera will reach the asteroid system two years later to examine the effects of the DART impact. Dimorphos, located about 181 million kilometers from Earth, will be studied in detail to improve the "kinetic impact" method as a viable planetary defense technique.

Hera will be the first spacecraft to carry cubesats to deep space, which will enhance its scientific capabilities. Besides refining asteroid deflection strategies, Hera will also help uncover more about the formation of the solar system.

The spacecraft itself is cube-shaped, with each side measuring 1.6 meters, and when fully deployed, the solar arrays will extend 11.5 meters. Weighing approximately 1150 kg when fully fueled, Hera will rely on its solar-powered arrays and a hydrazine propulsion system for its journey.

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