"Hera" launches in October How the ESA wants to protect the Earth from asteroid collisions

Humanity is no longer as helpless against asteroids from space as it was decades ago. "Hera" is now supposed to protect the Earth.

What was action-packed science fiction in Hollywood blockbusters such as "Armageddon" could become a realistic possibility. The European Space Agency Esa's "Hera" mission, named after a Greek goddess, is intended to contribute to this - it is due to be launched in October.

"Hera" is to investigate what the impact of the US space agency NASA's "Dart" probe on Dimorphos, the smaller part of a double asteroid, has caused. What does the 160-metre-long lump look like now? Does it have a crater, has it been deformed? How heavy is it? "Hera" will answer these questions," says asteroid expert Detlef Koschny, Professor of Lunar and Planetary Exploration at the Technical University of Munich. The mission is therefore an important contribution to the topic of planetary defense.

"Dart" (Double Asteroid Redirection Test) was launched in November 2021 and crashed into the asteroid in September 2022 at a speed of around 6.6 kilometers per second. The impact measurably changed the orbit of Dimorphos - a kind of moon of the larger asteroid Didymos. "This showed that we can change the orbit of an asteroid that may be on a collision course," says Koschny.

"We are now entering a new era of humanity in which we could have the possibility of protecting ourselves against the impact of an asteroid," said NASA after the impact.

Arming ourselves against the great danger

Impacts have shown several times in the history of our planet just how devastating larger asteroids can be. For example, a hit around 66 million years ago is considered to be the main cause of the extinction of the dinosaurs.

Nasa and Esa want to be better armed against such dangers in future. "Hera" is to be launched from the Kennedy Space Center in Florida on board a Falcon 9 rocket from the private space company SpaceX on October 7 at the earliest. 26 months later, the space probe will begin its scientific investigation.

"We have been preparing for months," says the head of the Esa Control Center, Simon Plum, about the upcoming launch. "We are making good progress and are confident that we will be as well prepared as possible." Like most Esa missions, "Hera" will be controlled from the control center in the German city of Darmstadt.

"Hera" has various cameras as well as laser and radar-based measuring systems on board, some of which are on small satellites called CubeSats, one of which is also due to land. These will be used to investigate the dimensions of the impact crater as well as the mass and density, surface, mineral composition and structure of Dimorphos.

Next mission already in preparation

Esa's space safety program in Darmstadt is already preparing another asteroid mission: "Ramses" (Rapid Apophis Mission for Space Safety) is to study the asteroid Apophis during its flyby of Earth in 2029. According to Esa, the lump, which is around 375 meters in size, will fly past Earth on 13 April 2029 at a distance of just 32,000 kilometers. This is very close by space standards - the moon is on average around 380,000 kilometers away from Earth.

According to experts, the impact of an asteroid of this size on Earth would probably have catastrophic consequences. For comparison: in February 2013, an asteroid only around 20 meters in size exploded over the Russian city of Chelyabinsk. Around 1500 people were injured by the blast wave, mostly by shattering window glass.