ESA Mission “Hera” to Explore Impact of Asteroid Collision

Much like NASA’s upcoming DART, or Double Asteroid Redirection Test, mission, to change the course of a heavenly body to see if it might be possible to protect the Earth from an asteroid collision, the European Space Agency’s “Hera” mission will check stats on how the earlier effort impacted the space rock.

At 1:20 AM EST on Wednesday, November 24, NASA will launch a  spacecraft from the SpaceX Falcon 9 Rocket in order that it can do its worst when it meets up with the asteroid on October 2, 2022.

There is no known threat at this time, but NASA wants to test their technology’s preparedness for the potential event that an asteroid seriously threatens the Earth. The preview briefing earlier this month featured members of DART’s team answering questions from the general public on its launch and mission.

SpaceX in California to launch DART on Wednesday

NASA will be sending the spacecraft out from Vandenberg Space Force Base in California.

DART aims to make impact with one of the asteroids, known as Dimorphos, at around 13,500 mph (21,726 kmh) almost an entire year after launching.

Dimorphos, which is over 500 feet wide, orbits a gigantic space rock called Didymos. Didymos is roughly five times the size of Dimorphos.

Within two years after the intentional collision, the ESA will see just how much Dimorphos was affected — and even possibly take a look inside the two asteroids for the very first time.

Two “cubesats” that are part of the Hera mission will measure the interior of the asteroid, if all goes as planned.

Intentional asteroid collision will give astronomers invaluable information on asteroid deflection

Initially, the plan was for Hera to witness the DART collision, but funding issues within the EU led to a series of delays. Arriving approximately two years after the collision, Hera will now be tasked with what astronomers say is the “final outcome” of the impact, after all is said and done.

By then it will be known by Earth-based observation whether or not DART reached its goal of changing its orbit around the larger Didymos.

As it is, there is much that is currently unknown about the two heavily objects and how they interact with each other. In addition, the EDA states, any information Hera can glean will help researchers target future missions that will be sent to deflect asteroid paths.

Michael Kueppers, Hera project scientist at the ESA, told Space.com “Hera is currently on track to launch in October, 2024. It will arrive in late 2026 or early 2027.

“Although we originally wanted to observe the impact directly, there are certain advantages to arriving later. We will be able to see the final outcome, which may be the most relevant point from the planetary defense point of view.”

NASA will photograph impact of collision first, ESA craft will map subsequent aftermath

NASA states that DART will photograph the two asteroids with the high-resolution DRACO (Didymos Reconnaissance and Asteroid Camera for Optical Navigation) camera before it slams into Dimorphos.

The NASA craft will be able to stand in for the ESA spacecraft that would have been on hand to photograph the event by launching a cubesat, which will take what the agency says are “basic images” of the aftermath of the collision.

Hera will eventually make it to the site of the crash and use a more advanced suite of instruments which will allow it to analyze not only the outcome of the collision, but the structure of Didymos and Dimorphos and their chemical makeup as well.

“Right now, we know quite well how the two asteroids orbit each other and how they together orbit the sun,” Kueppers explains, adding “We know that the larger Didymos is about 800 meters (2,600 feet) across and the smaller Dimorphos about 170 meters (560 feet) across. But we don’t know their shapes, we don’t know the mass of Dimorphos and we have no information about their composition and chemistry.”

Astronomers believe it is likely that Didymos is not a single rock but rather a “rubble pile,” a collection of boulders and pebbles the tis only held together by gravity in a loose formation; the same might be true of its smaller brother, Dimorphos.

First time in history crater with observed, real-time impact can be measured

If the bodies are solid, there will be minimal damage, while if they are just loose collections of rocky fragments, they will likely fly off into space.

“The more detail we learn, the better we will be able to scale up the mission to achieve a desired outcome if it was ever needed one day to protect Earth,” Kueppers says, noting “We would need to be better able to much better predict the outcome of such an impact if it’s ever needed in a real case.”

One of the cubesats which will be aboard Hera, called Juventas, will carry a new radar instrument which will allow it to analyze the interiors of the two asteroids. This would be a first for astronomy if it is successful, Kueppers states.

“The cubesat carries a radar instrument that will send radio waves into the asteroids and measure the reflection,” said Kueppers. “These waves will penetrate the asteroids and reveal the subsurface structure.”

The other cubesat, called APEX (or Asteroid Prospection Explorer) will measure the impact crater that was made by the DART collision.

Both cubesats will even attempt to land on Dimorphos at the end of their respective missions, the ESA says.

Because the ESA will launch later than originally intended, this means that there will be a much clearer view of what happens after the DART mission.

“We have many craters on the moon and asteroids in the solar system,” Kueppers explains.

“But this is a unique case where we can investigate a crater where we know exactly the properties of the impacting object. That will help us to significantly advance our understanding of the physics of cratering and the scaling of craters, which is a valuable piece of information for both, science and planetary defense.”