HERA Mission: The Portuguese Contribution to Planetary Defense

In Armageddon, a 1998 film that became a classic, a team races against time to prevent an asteroid from destroying Earth. To ensure that fiction does not become a reality, the proper response to the threat of an asteroid lies not in explosions or improvised heroism but in science and innovation. This is where the HERA mission by the European Space Agency (ESA), comes into play. Representing the European component of an international effort to defend the planet, it will be launched this Monday, October 7th, aboard SpaceX’s Falcon 9 rocket from Cape Canaveral, Florida.

Portugal plays a prominent role in this pioneering mission, designed to analyse a binary asteroid system: Didymos and Dimorphos – one of over 1.3 million known asteroids in the Solar System – through the technological innovation of the companies Tekever, FHP, and GMV, which developed crucial solutions for the mission’s success. This European mission will assess the impact of NASA’s DART probe, which collided with the asteroid Dimorphos in 2022. The HERA probe will make the first detailed analysis of the crater created by the DART impact and the orbital change that the smaller of the two asteroids – which orbits the main asteroid Didymos – underwent at that time.

The first asteroid deflection test in history aimed to alter the orbit of Dimorphos, a 160-meter diameter asteroid orbiting Didymos, the main body of the system with a 780-meter diameter. The test was considered a success, but to ensure that the lessons learned can effectively deflect asteroids of different sizes and structures that might one day threaten Earth, scientists need more information on the impact and on Dimorphos itself.

Equipped with high-resolution cameras, laser altimeters, and infrared spectrometers, the HERA probe will map the surface and internal structure of Dimorphos, allowing for the study of the efficiency of kinetic impact as a planetary defense method. This international collaboration turns fiction into a real strategy for planetary defense, paving the way for a new era of space safety.

The Portuguese participation was made possible after Portugal subscribed to the mission’s envelope at the ESA Space19+ Ministerial Summit and later reinforced it at the 2022 Ministerial Summit.

“The HERA mission is a landmark not only for planetary defense but also for Europe and Portugal. The analysis of the DART probe impact will provide crucial data to understand the effectiveness of this method and its replication to deflect asteroids that may threaten Earth. The Portuguese participation in the mission demonstrates the capacity and talent of our ecosystem to contribute with cutting-edge technologies to this kind of space security project,” says Inês d’Ávila, space security program manager at the Portuguese Space Agency.

Communication, Navigation, and Protection

To closely analyse Dimorphos, the HERA probe will launch two CubeSats capable of mapping the surface in detail, characterising the dust, and assessing the asteroid’s internal structure. The HERA mission will then attempt to land on the asteroid system and carry out further measurements.

This mission is only possible thanks to the contribution of the Portuguese company TEKEVER, which developed an innovative inter-satellite communication system (ISL – Inter-Satellite Link) capable of enabling the three satellites to communicate with each other and determine their relative distance. “The ISL solution was based on GAMALINK, which had already been developed for previous missions, notably for Proba-3,” explains Pedro Rodrigues, Commercial Development Director at TEKEVER Space.

Even though it builds upon developments made in previous space missions, the HERA mission brought two major technological challenges to the company: the miniaturization and requalification for CubeSat platforms, and the adaptation of the communications protocol to support a network of three satellites. “The first challenge was overcome, on one hand, by working closely with the teams that developed the CubeSats to achieve a compatible design, and on the other hand, by using TEKEVER’s capability to perform environmental tests (vibration and thermal vacuum) to validate and mitigate the risk of the design itself,” he explains. Furthermore, to address the second challenge, “it was necessary to develop a testing system that recreated the mission’s topology and validated the software development even after the delivery of the flight models.”

In parallel, GMV was responsible for developing the autonomous Attitude, Orbit Control, and Navigation system (GNC in English) for the mission, which allows the HERA probe to approach up to 1 kilometer from the asteroid Dimorphos. “The development of a GNC system for asteroids is a huge challenge – not just technologically, but also humanly,” explained Francisco Cabral, AOCS Technical Leader at GMV Portugal. One of the main difficulties was navigation in conditions of extremely reduced gravity. “Any manoeuvre error can have devastating consequences, and we had to design and verify a system capable of performing manoeuvres with millimeters per second precision,” detailed Francisco Cabral, highlighting the need for precision in each manoeuvre. The large distance from Earth requires that some of these manoeuvres be autonomously calculated on board, using images captured by onboard cameras.

“Being so close to the asteroid, it fills the images taken (thus robbing us of the perception of its center), and it was necessary to develop an innovative system that we called ‘feature tracking,’ which will allow us to navigate very close distances.”

The HERA mission would not be possible without effective thermal protection, and it was exactly this that the FHP provided for the mission. The company supplied the multilayer thermal protection (MLI) for the probe, fundamental for its performance throughout the mission, as it protects the probe from the extreme temperatures of space and ensures its proper functioning. “The thermal protection covers practically all the external (and some internal) elements of the probe, so its good performance is fundamental for the probe’s success,” said Miguel Santos of FHP, emphasizing that this contract strengthened the company’s ties with OHB, the main contractor, with whom they have “been collaborating for more than a decade,” and also provided “the opportunity to work directly with ESA on a planetary defense mission, of great relevance to Humanity.”

Miguel Santos emphasizes the need for meticulous design and assembly to ensure the thermal stability of the probe, particularly in a space environment with extreme temperatures. In addition, the tight deadline for assembly presented an additional challenge: “FHP worked from the beginning against the clock, both in design and production and assembly phases.”

Innovations and Impact on the Future of Space

The integration of these technologies represents a unique approach in the HERA mission and demonstrates the innovative capacity of national companies. Indeed, the mission is only possible thanks to the ISL system developed by Tekever: “The innovative configuration of the HERA mission, with two smaller satellites responding to a main satellite, is only possible with an ISL that allows them to communicate with each other,” says Pedro Rodrigues, adding that TEKEVER’s GAMALINK is a “technology enabler for this type of mission.”

Moreover, with pioneering radio science experiments that could initiate a new wave of scientific missions, TEKEVER expects to be involved in future “planetary defense missions that will follow HERA, contributing with all the knowledge gathered and technology developed in this mission.”

This sentiment is shared by FHP, which hopes that the experience accumulated in this mission will serve as a basis for participation in future missions. “Although the mission’s objective is exploratory and to demonstrate the ability to deflect the course of an asteroid, we end up being actors and having the knowledge to repeat this type of mission should a real threat arise in the future,” says the FHP representative, also stating that this was an opportunity to improve internal processes. “FHP implemented improvements in its processes to increase the degree of automation and reduce errors, using internal automation tools.” Furthermore, “FHP tested and plans to continue using augmented reality to improve the efficiency of its processes, particularly in design, production, and assembly phases.”

Finally, GMV’s GNC technology, inspired by approaches used in autonomous land vehicles, paves the way for future planetary defense missions in which the company is already working. “Starting from such an advanced base, GMV will be able to develop faster and with greater confidence in its quality,” concluded Francisco Cabral, signaling the potential application of the autonomous navigation system beyond planetary defense.

“The HERA mission is not just an opportunity to test new space technologies but also to demonstrate the excellence of Portuguese engineering,” says Inês d’Ávila, who believes that “the contribution of companies like TEKEVER, GMV, and FHP shows how Portugal is at the forefront of innovation in critical areas such as space communications, autonomous navigation, and thermal protection.” “Each of these solutions is essential to ensuring the success of the HERA mission and, consequently, to preparing humanity to respond to potential space threats in the future.”

The HERA mission is an example of how science, innovation, and international collaboration, with Portugal at the forefront, are preparing humanity to respond to potential space threats, turning the unknown into opportunities for knowledge and planetary protection. If all goes well, the HERA probe will pass by Mars in March next year and reach the asteroid, more than 177 million kilometers from Earth, in December 2026.