NASA has intentionally crashed a 570 kg (1,260 lb) spacecraft into the surface of a wandering asteroid, in order to test our ability to avoid a potentially devastating collision with Earth.
Since its birth some 4.5 billion years ago, Earth has been under constant bombardment from material left over from the creation of the solar system. Most of these pieces of interplanetary debris are so small that they break apart when they hit Earth’s dense atmosphere.
However, once every few million years, a monstrous asteroid large enough to survive entry into the atmosphere strikes the surface of our planet with catastrophic force.
the latest monster impact It happened approximately 66 million years ago, when an asteroid 6 miles (10 km) wide collided with our planet and opened a huge crater, the remains of which can still be found in the Yucatan Peninsula today.
A combination of the devastation caused by the initial impact and the environmental changes brought about by the resulting fallout sounded the death knell for 75 percent of all animal life on Earth and effectively ended the age of the dinosaurs.
It is entirely possible that the impact of another huge asteroid could damn the human race to extinction Unlike the dinosaurs, however, we may have the technological capabilities and foresight to avoid that fate.
NASA’s Double Asteroid Redirection Test (DART) is the first step on the road to developing a planetary defense against colossal asteroids. Compared to Hollywood movies dealing with similar themes, the mission itself is relatively simple. There is a distinct lack of nuclear weapons, large drills or Bruce Willis-es.
Instead, NASA has opted to command a lone, and obviously uncrewed, probe to hit an asteroid head-on as it travels at 14,000 miles per hour to see how the impact would change its orbit. The idea is that if it detects a potentially dangerous asteroid early enough, it will only take a small deflection to send it onto a safer path.
“Planetary Defense is a global unifying effort that affects everyone who lives on Earth,” says Thomas Zurbuchen, Associate Administrator for the Science Mission Directorate at NASA Headquarters in Washington. “Now we know that we can target a spacecraft with the precision necessary to hit even a small body in space. Just a small change in its speed is all we need to make a significant difference to the path an asteroid travels.”
The mission target is the 530ft (160m) wide asteroid/moon Dimorphos., orbiting a larger 2,560-foot (780-m) wide asteroid known as Didymos as it moves through the solar system.
NASA has made sure to emphasize that none of the asteroids posed a threat to Earth either before or after the test.
In the hours before impact, DART used sophisticated navigation software to interpret images captured by its onboard camera to guide itself autonomously. During this time, the doomed probe was able to capture detailed images of Dimorphos’ bleak, debris-strewn surface.
IMPACT SUCCESS! view from #DARTMIssionDRACO Camera, as the vending machine-sized spacecraft successfully collides with the asteroid Dimorphos, which is the size of a football stadium and poses no threat to Earth. pic.twitter.com/7bXipPkjWD
— NASA (@NASA) September 26, 2022
Finally, on September 26, at 7:14 pm Easter time, after years of development and 10 months of navigating interplanetary space, mission managers announced that DART had successfully achieved its goal.
Following the impact, several ground-based and orbiting observatories observed the asteroid pair, including the James Webb Space Telescope – which sought to determine how much the impact had changed Dimorphus’s trajectory.
More specifically, the global scientific community wanted to know how the collision had altered the amount of time it takes for the smaller asteroid to orbit its bigger brother and to observe the behavior of the material that was ejected from its surface.
The heavy-duty telescopes were aided in this task by a tiny Italian-made cubesat, which had hitchhiked with the DART mothership, and was deployed 15 days before the end of the mission.
The sole purpose of the small satellite is to capture images of DART and the damage inflicted on the asteroid system from a different perspective. However, due to the tiny size of its antenna, it will take weeks to send the images back to Earth.
Computer modeling of the event projects that the impact will have reduced Dimorphus’s orbital period by about 10 minutes, or 1 percent. In-depth observations will be compared to these models to refine them and improve scientists’ understanding of asteroids.
Regardless of the final orbital change, the DART mission can only be considered a success. It has shown that an unmanned probe can autonomously perform the calculations and trajectory corrections necessary to successfully collide with an asteroid, even when it is orbiting a larger body.
The asteroid duo will be the target of the European Space Agency’s Hera mission four years from now, in 2026, during which a mothership and a cubesat will make follow-up observations.
“This mission, the first of its kind, required incredible preparation and precision, and the team exceeded expectations in every way,” says Ralph Semmel, director of the Johns Hopkins Applied Physics Laboratory in Maryland. “Beyond the truly exciting success of the technology demonstration, DART-based capabilities could one day be used to change the course of an asteroid to protect our planet and preserve life on Earth as we know it.”
