Hera: European mission to investigate asteroid diverted by NASA takes off

A European spacecraft and two shoebox-sized satellites are about to be launched to examine the consequences of the DART mission (or Double Asteroid Redirection Test) by NASA, which intentionally collided with an asteroid called Dimorphos and altered its orbit two years ago.

THE Hera mission of the European Space Agency (ESA) took off aboard a SpaceX Falcon 9 rocket this Monday morning (7) from NASA’s Kennedy Space Center in Florida.

The spacecraft and its two companions, the CubeSat satellites, are scheduled to arrive at the asteroid Dimorphos and the larger asteroid it orbits, called Didymos, in late 2026. Together, the three spacecraft will conduct an “accident scene investigation” to resolve the remaining mysteries about the double asteroid system, according to ESA scientists.

NASA designed the DART mission to conduct a large-scale evaluation of asteroid deflection technology in the name of defending our planet. The agency wanted to see if a kinetic impact — like crashing a spacecraft into an asteroid moving at 6 km per second — would be enough to change the movement of a celestial object in space.

Neither Dimorphos nor Didymos pose a danger to Earth. Still, the double asteroid system was a perfect target to test deflection technology because Dimorphos’ size is comparable to asteroids that could threaten Earth.

Astronomers have been using ground-based telescopes to monitor the impact’s aftermath since the collision in September 2022, and they determined that the DART probe successfully changed the way Dimorphos moves, changing the lunar asteroid’s orbital period — or how long it takes to do a single lap around Didymos — in about 32 to 33 minutes.

But many questions remain, including whether the DART spacecraft merely left behind a crater or whether its impact completely reshaped Dimorphos. And determining the exact composition of the double asteroid system, as well as the consequences of the DART mission, could help space agencies further refine technology that could deflect asteroids that could affect Earth in the future.

“Hera will close the loop by providing us with the final result of DART’s impact in detail,” said Patrick Michel, director of research at the French National Center for Scientific Research and principal investigator on the Hera mission.

Embarking on a two-year journey

When the Hera spacecraft, the size of a small car, arrives at the double asteroid system in October 2026, it will be almost 195 million kilometers from Earth. Didymos is a mountain-sized asteroid with a diameter of 780 meters, while Dimorphos is similar in size to the Great Pyramid of Giza, with a diameter of 151 meters.

But first, Hera will fly past Mars in mid-March 2025, which will give the spacecraft the extra boost it needs to reach Didymos and Dimorphos two years after launch.

In addition to testing its suite of 11 instruments, Hera will fly 6,000 kilometers from the Martian surface. Hera will also observe one of Mars’ two moons, called Deimos, from a distance of 1,000 kilometers.

Scientists think both of Mars’ small, irregular moons could be asteroids that were captured from the main asteroid belt, located between Mars and Jupiter. The Hera flyby will capture data for Japan’s Martian Moons eXploration probe. This mission, scheduled to launch in 2026, will survey both moons of the red planet and land a small rover on Phobos, collecting samples from that Martian moon that can be returned to Earth.

Hera will next reach the orbit of the Didymos system in October 2026, spending six weeks observing both asteroids to gain more details about their shapes, masses, and thermal and dynamic flybys, while also identifying points of interest for further future flights. nearby.

After the six-week survey, Hera will launch its two CubeSats called Juventas, the Roman name for a daughter of Hera, and Milani. Milani was named in honor of Andrea Milani, a mathematics professor at the University of Pisa in Italy who died in 2018. Milani is known for creating the first automated system to calculate probabilities that an asteroid could impact Earth in the future.

Juventas is equipped with a radar instrument that will be able to peer deep below the surface of space rocks, while Milani has a multispectral imager to map minerals and dust on both asteroids. The instrument can capture a wider range of colors than the human eye can see to determine the composition of individual rocks and the dust environment around them.

The CubeSats, which have their own propulsion systems, will use inter-satellite links to communicate with Hera and relay its findings to Earth, Michel said.

Over the course of 10 weeks, Hera will perform observations that will take it closer to the asteroids’ surface, eventually reaching within 1 kilometer. Several overflights of the impact site created by DART at Dimorphos are expected.

Eventually, Hera may land on Didymos, which could serve as the end of its mission or a limited extension if it survives the landing, while CubeSats could make similar experimental landings on Dimorphos. Neither spacecraft is designed specifically for landing, but will slow down enough to operate cameras and instruments on the asteroids after landing, according to the agency.

Analyzing the consequences

Humanity’s most detailed glimpses of the double asteroid system have been brief.

Images captured by DART and a small satellite called LICIACube, which separated from the spacecraft to capture images of the collision and resulting debris cloud, have fueled much of the impact-related research released since September 2022.

But when Hera visits Dimorphos, the situation could be very different, Michel said.

“What’s most exciting to me is that although we have excellent images of Didymos, Dimorphos and their surface taken by the DRACO camera aboard the DART spacecraft before their collision, we already know that the same bodies and surface areas will have nothing to do with what these images showed us when Hera takes new images”, said Michel. “It still feels like discovering new worlds. And the coolest thing is that we will know why they are new or different, since DART gave us all the initial conditions that led to their transformation.”

Data collected by the mission can help scientists understand the internal structure of each asteroid. When DART struck Dimorphos, a cloud of debris extended more than 10,000 kilometers into space and persisted for months—enough to create the first man-made meteor shower that may be visible on Mars and Earth in the future.

Scientists are eager to know whether Dimorphos is a rubble asteroid, held together by gravity with large voids inside, or a solid core surrounded by rocks and gravel, Michel said.

Understanding all possible aspects of Dimorphos is crucial, mission scientists say, because if an asteroid that size hit Earth, it could destroy an entire city.

Although the DART mission was a “surprising success,” Michel said Hera is needed to understand the final result of the DART deflection test and measure its effectiveness.

“I hope this can serve as a source of inspiration for other missions dedicated to planetary defense and solar system exploration,” he said.

Spacecraft takes a photo of the Earth and the Moon side by side seen from space; look

This content was originally published in Hera: European mission to investigate asteroid diverted by NASA takes off on the CNN Brasil website.

Source: CNN Brasil