Diego Escorial, the Spaniard who will prevent an asteroid from colliding with Earth at the helm of the Hera mission

More than 7,500 kilometers away, at the European Space Agency’s Space Operations Center in Darmstadt (Germany), Diego Escorial Olmos held his breath with his ESA colleagues. This 50-year-old Madrilenian, who now looks like a 21st century Valle-Inclán, Since 2020, he has devoted himself body and soul to Hera as a systems engineer.

“I am the person who coordinates the technical part of all the different subsystemsboth in the design phase and in the testing and integration phase of the mission”, he says as if it were the most normal thing in the world during a video conference with EL ESPAÑOL – Omicrono.

In the videos of the launch shared by the space agency, you can see the spectacular liftoff and the moment when Hera detaches from the second stage of the rocket, but also the overwhelming emotion of the team responsible for the missionincluding Escorial himself. “It’s been very exciting,” he explains, with a lower heart rate, but still very aware that everything is going well.

“We’ve been working tirelessly on Hera for four years. We’ve done all the testing and preparation necessary to launch the 7 and it hasn’t been easy getting here. We knew we were launching during hurricane season, so it He was a very big stranger. You watch the news and see that the hurricane continues to grow, you become very nervous. But still, on Monday morning, we were all optimistic that it would launch…and finally, it launched.”

From Don Quixote to Hera

The launch of Hera is a key milestone in the Asteroid Impact and Deflection Assessment (AIDA) project, a collaboration between NASA and ESA aimed at testing the effectiveness of the planetary defense formula composed of crash a spaceship into the heart of a potentially threatening asteroid. DART was responsible for the first part of the mission on November 26, 2022, when this device successfully collided with the asteroid Dimorphos.

Hera is now going to the same place, 11 million kilometers from our planet, to study the composition of the asteroid and verify the consequences of the impact. “For this, we had to develop very interesting technologies, which will allow us to go on site and investigate in detail what happened. Even if it is not new, it comes from a long time ago. a long time…”, explains Escorial.

It all started more than twenty years ago, when The all-European mission was first proposed under the Cervantine name of Don Quixote.. Instead of gigantic windmills, the ships Hidalgo and Sancho would be confronted with potential meteorites. “We were going to take care of both the ship that was going to collide with the asteroid and the orbital probe that was going to study the impact. But we didn’t have the money and the mission disappeared. Then it disappeared. was reborn in 2014 in cooperation with NASA and that’s how we got here”, recalls the aerospace engineer without any nostalgia, even if he was also part of this team with other Spaniards.

Is playing this kind of cosmic billiards the best way to defend our planet from a possible asteroid impact? “It depends on several factors. First you need to know which asteroid is arriving and its characteristicsthis is why a ship like Hera is needed to act as an observer. “The method we use and test is kinetic impact, which is most appropriate for some asteroids, not all.”

In the case of larger stellar objects, things get complicated. “It’s pure physics. If it’s very big, like the one that wiped out the dinosaurs, what it would take to crash into it must be huge too, and today we can’t launch a 300,000 ton device But for “For small asteroids like Dimorphos (160 meters in diameter), which can still cause quite a bit of damage locally, this method is perfect.”

The most important part of planetary defense, Escorial recalls, “is when you detect the asteroid. If you do it 20 years in advance, provided you move it a little, It will disintegrate over time and eventually move apart a little. If we detect it three months before arriving, it’s much more difficult and we have to deal it a very big blow.”

In fact, recent scientific studies support using nuclear devices to deflect asteroids as the only viable option when there is little reaction time or when its dimensions are much more threatening than those of Dimorphos. “Launching a nuclear bomb on a rocket, as you can imagine, has some risks and a lot of people would say that maybe it’s not a good idea. I also wouldn’t rule it out completely, because I don’t We haven’t studied it in detail, but our method is much safer, provided that the collision trajectory is discovered well in advance.

To Mars and beyond

From time to time, at the Escorial it is difficult for him to find the precise word in Spanish. The working language at ESA is English and its team includes people from many countries, “from Finland to Spain”. For him, this “healthy and interesting” multicultural environment has only one problem: “getting used to eating at 12 in the morning,” he says with a slight smile.

Immediately after this conversation, Hera’s systems engineer is scheduled to begin his satellite monitoring duty, just at the end of LEO (low Earth orbit), which is equivalent to the first three days of the mission’s life. “So far we have deployed the solar panels, we have pointed them towards the sun, we have pointed them towards the Earth and we are using the inertia wheels. We are all very happy, because the mission is complex. This n satellite is not simple, several technologies had to be developed and. so far everything is working as expected“.

Until a few days ago, and in the two periods during which he worked at ESA —from 2002 to 2009 and from 2016 to today— Escorial developed most of his work at the European Center for Space Research and Technology, in Noordwijk (Netherlands).

This is where all the necessary tests were carried out to prepare Hera and its nanosatellites, Juventas and Milani, for withstand the extreme conditions of space and a journey of 11 million kilometers“The further you go from Earth, the more communication capabilities you need to have. And the further you go from the Sun, the colder the satellite becomes, so you have to heat it and the less energy you produce with your solar panels,” explains Escorial. “This is why you have to design your satellite according to these situations and give it the appropriate autonomy.”

Beyond the design, a task completed in 2022, ESA engineers led by Escorial were responsible for the integration, “something similar to Screw all the things together and connect them“Finally, the spacecraft underwent an extensive testing phase, to “demonstrate here on the ground that the satellite will be able to do whatever you want it to do under the conditions it will have upon launch.”

“We are on top of a ‘bomb’ and it is going to vibrate a lot, so we have to prove that it will survive this phase. Next in orbit, it will be subjected to different thermal and electromagnetic environments…Here we place the satellite in these conditions, to show that everything will work the way we think it will,” he says.

Despite the intensive testing carried out at ESTEC, problems or failures may occur in the measurements, the accuracy of which is essential. “The software part is what gives us some flexibility,” as demonstrated by the longevity of Voyager 2, which continues to receive updates 47 years after its launch. “If an instrument communicates late with the computer, We can always put a plan in place to adapt and resolve the situation.. Just in case, we have also introduced redundancy into the satellite, so that in the event of a failure, there is a backup to continue operating. »

If all goes well, forecasts estimate that Hera will reach her destination in the fall of 2026, where she will spend 6 months studying the celestial bodies. However, the first interesting scientific data will be sent to Earth in mid-March 2025, when The ESA is expected to be able to calibrate the probe’s instruments during its flyby to Mars where, in addition to taking advantage of its gravitational field to propel itself, it will obtain images of the planet and its moon Deimos.

For this, the systems designed and developed by Spanish companies, of which Escorial is proud, will be fundamental. “The Spanish contribution to Hera was quite significant. We had GMV who took care of the GNC (guidance, control and navigation), Thales Alenia Spain took care of the telecommunications and Sener supplied the low gain antenna” , to which must be added the participation of Alter and EMXYS. “Actually, The GNC subsystem is one of the most critical in the missionsince Hera must be able to target the asteroid autonomously.”

When there are a few minutes left to finish the interview, Escorial says: “Sorry, I have to leave you, they need me.” It is the work of one of the monitoring managers who a mission of 363 million euros which will be key to defending the Earth from the impact of asteroids, carrying out its long odyssey in the depths of the solar system.