But the real test for this asteroid’s deflection technology will come in September 2022, when the spacecraft reaches its destination, to see how it impacts the motion of a near-Earth asteroid in space.
Near-Earth objects are asteroids and comets whose orbits place them within 30 million miles (48 million km) of Earth. Threat detection of potentially harmful near-Earth objects, or NEOs, is a major focus of NASA and other space organizations around the world.
Asteroid Didymos and its Moon
In Greek, Didymos means “twin”, which is a sign that the asteroid – which is almost half a mile (0.8 km) across – forms a binary system with the smaller asteroid, or moon – 525 feet (160 meters) in diameter – discovered two decades ago. Kleomenis Tsiganis, a planetary scientist at Aristotle University of Thessaloniki and a member of the DART team, suggested that the moon be named Dimorphos, which means “two forms”.
This is the perfect time for the DART mission to happen. Didymos and Dimorphos will be relatively close to Earth – within 6,835,083 miles (11 million km) – in September 2022. The spacecraft will accelerate at about 15,000 miles (24,140 km) per hour, aiming for into the Dimorphos, said Nancy Chabot, DART chief coordinator at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland.
An onboard camera, called DRACO, and automated navigation software will help the spacecraft detect and collide with the Dimorphos. DRACO stands for Didymos Reconnaissance & Asteroid Camera for OpNav.
The purpose of the mission was to deliberately crash into Dimorphos to change the asteroid’s motion through space, according to NASA. This collision will be recorded by LICIACube, or Light Italian Cubesat for Imagery of Asteroids, a companion cube satellite provided by the Italian Space Agency. It was the Italian Space Agency’s first deep space mission.
The briefcase-sized CubeSat will travel over the DART and then be deployed from it before impact so it can record what happens. Three minutes after impact, CubeSat will fly with Dimorphos to take photos and video.
Elena Adams, DART mission systems engineer at the Johns Hopkins Applied Physics Laboratory, said video of the collision would be streamed back to Earth, which would be “exciting”.
“Astronomers will be able to compare observations from Earth-based telescopes before and after the kinetic impact of DART to determine the period,” said Tom Statler, DART program scientist at NASA Head How has the orbit of the Dimorphos changed? “It’s an important measurement that will tell us how the asteroid responds to our deflection attempt.”
Several years after the collision, the European Space Agency’s Hera mission will conduct a follow-up investigation of Didymos and Dimorphos.
While the DART mission was developed for NASA’s Planetary Defense Coordination Office and is managed by the Johns Hopkins University Applied Physics Laboratory, the mission team will work with the Hera mission team under collaboration. An international collaboration known as the Asteroid Impact & Deviation Assessment, or AIDA.
“DART is the first step in experimental approaches to dangerous asteroid deflection,” said Andrea Riley, executive director of the DART program at NASA Headquarters. “Potential asteroids are of global concern and we are pleased to work with our Italian and European colleagues to collect the most accurate data possible from the deflection demonstration.” this kinetics.”
A first mission
Dimorphos was chosen for this mission because of its size relative to asteroids that could pose a threat to Earth, but the binary asteroid system itself is not a threat to Earth.
The spacecraft is about 100 times smaller than Dimorphos, so it won’t obliterate the asteroid.
“This won’t destroy the asteroid, but just give it a small nudge and deflect its path around the larger asteroid,” Chabot said. This means there is no chance of changing the asteroid’s orbit to make it more of a threat.
The fast impact will only change Dimorphos’ speed as it orbits Didymos by 1%, which doesn’t sound like much – but it will change the moon’s orbital period by more than a minute. That change can be observed and measured from ground-based telescopes on Earth.
Dimorphos completes an orbit around Didymos every 11 hours and 55 minutes. Andy Cheng, DART investigation lead at the Johns Hopkins Applied Physics Laboratory, said if the impact was successful, it would change that time interval by at least 73 seconds.
Measuring the angular momentum between the spacecraft and Dimorphos will show how much it takes to change an asteroid’s direction.
“If one day an asteroid is discovered on a collision course with Earth, then we’ll get an idea of how much momentum we need to make the asteroid slide,” says Cheng. from the Earth”.
Planetary defense strategies
While no asteroid currently has a direct collision with Earth, there are a large number of near-Earth asteroids – more than 27,000 of all shapes and sizes.
“The key to protecting the planet is to find them well before they’re an impact threat,” said Lindley Johnson, planetary protection officer at NASA Headquarters. “The principle of all of them is to change an asteroid’s orbital speed only by a small amount. Changing the asteroid’s orbital speed in its orbit changes its orbit so in In the future, it won’t be in the right place. It will impact the Earth.”
Three years after the collision, Hera will come to study the details of Dimorphos, measure the physical properties of the moon, study the DART collision and the moon’s orbit.
This may sound like a long wait between impact and follow-up, but it is based on lessons learned from the past.
In July 2005, NASA’s Deep Impact spacecraft launched an 815-pound (370 kg) copper collision into a comet, Tempel 1. But the spacecraft could not see the crater due to that impact. Release tons of dust and ice. However, NASA’s Stardust mission in 2011 was able to characterize the impact – a 492-foot (150-meter) fracture.
Together, the valuable data collected by DART and Hera will contribute to planetary protection strategies, especially in understanding what kind of force is needed to change the orbit of a near-Earth asteroid that can be detected. may collide with our planet.
After analyzing the mission’s results, “this technique will be part of the toolbox where we are beginning to build capabilities to deflect an asteroid,” Johnson said.
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