HERA, an Eye on DART’s Mission Results

In the realm of space exploration, asteroids have long been a topic of interest. These rocky objects, some of which are the remnants of the early solar system, can tell us a great deal about the formation and evolution of our planet. But they can also pose a threat, potentially colliding with Earth. That’s why the European Space Agency (ESA) is planning to launch the HERA mission, which aims to explore and understand the composition, structure, and behavior of asteroids.

Aim the target

The HERA mission aims to study the effects of a high-velocity impact on the near-Earth binary asteroid system, Didymos, and its satellite, Dimorphos, which has already been impacted by the DART mission on Sept. 26, 2022.

 These missions are part of a larger international collaboration called the Asteroid Impact and Deflection Assessment (AIDA). AIDA is a joint undertaking between NASA and ESA. The mission’s primary goal is to study the effects of the DART impact on Dimorphos and develop methods for deflecting or mitigating such a catastrophic event which could be the effect of the asteroid on our planet.

En route to the twins

The HERA spacecraft will perform a series of experiments and observations to achieve this goal. The spacecraft itself will be launched on a Falcon 9 block 5 rocket in 2024 and will journey to the target. Didymos is an Apollo-class near-Earth asteroid (this class of asteroids includes objects that are potentially dangerous to the Earth). Discovered in 1996 is a binary asteroid, meaning it consists of two celestial bodies, one larger and one smaller. The smaller object is known as Dimorphos.

Hunger for information

When the HERA spacecraft arrives at Didymos, it will spend several months studying the asteroid and its little twin. This will include a detailed analysis of the asteroid’s composition, surface characteristics, internal porosity, and internal structure. In particular, Hera will be the first mission to measure the subsurface and internal structures of an asteroid. Also, the entire moon, Dimorphos, will be mapped. 

Looking at the impact area of DART the probe will measure how much momentum transfer depends on the density, porosity, and characteristics of the asteroid’s surface, crossing the data elaborated by the observation of the internal structure, and what proportion of the kinetic energy is transferred in the fragmentation and restructuring of the asteroid or the kinetic energy of the ejected materials as dust or micro fragment.

Tons of tools on board 

HERA is equipped with a suite of advanced scientific instruments designed to collect detailed information about the Didymos system. These instruments include:

• Asteroid Framing Cameras (AFC). The main instruments of Hera are the two AFC cameras (Asteroid Framing Cameras), developed by the company JenaOptronik.
• Thermal Infrared Imager (TIRI). TIRI is a thermal infrared imager provided by JAXA, the Japanese Space Agency.
• PALT (Laser Range Finder). PALT is a micro-Lidar planetary altimeter using a laser emitting an infrared light beam, PALT also supports spacecraft navigation, from fly-by to landing operations.
• Hyperspectral imager – HyperScout. HyperScout will contribute to the geological and compositional investigation of the asteroid. Developed by Cosine Research in the Netherlands, this is a specific version developed for Hera, different from the standard version.
• Radio Science Experiment (RSE).  The experiment will measure the mass of the two asteroids making up the binary system. The characteristics of their gravity field, their rotational speed, and their orbits will be measured using radio wave disturbances caused by the Doppler effect.
• CubeSat

Two little companions

HERA will also carry two CubeSats, which are small satellites that will be deployed in proximity to the asteroid to support the main spacecraft’s observations and gather additional data. Two CubeSat-type nano-satellites, named Milani and Juventas, will be essential to the RSE experiment by contributing to both surface measurements and observations. Milani is dedicated to the visual inspection and dust detection of the Didymos asteroid monitoring DART impact area. Juventas built by GomSpace is projected to study the geophysical characterization of Dimorphos as a gravity field, interior structure, and surface properties.  

A shield for humanity 

Overall, the HERA mission represents a significant step forward in our understanding of asteroids and their potential impact on Earth. Both this mission and DART contribute to studying the behavior of these objects and developing new strategies for planetary defense, we can better protect our planet and potentially even prevent a catastrophic event. With the collaboration of multiple international organizations and cutting-edge technology, HERA has the potential to make significant contributions to the field of planetary defense and advance our knowledge of the universe.