After 10 months of flight in deep space, NASA’s Double Asteroid Redirection Test (DART) successfully impacted its target asteroid on Sept. 26. This marks the first time humanity has altered the course of an asteroid, as well as a potential step toward the development of a global planetary defense system. 

DART, a joint venture between NASA and the Johns Hopkins Applied Physics Laboratory, was intended to test NASA’s ability to intentionally collide a spacecraft with an asteroid to deflect it—a technique known as kinetic impact that could eventually be used to deflect Earth-bound asteroids. According to NASA’s website, DART’s target was Dimorphos, a small asteroid about 170 meters in diameter that currently orbits a larger asteroid—Didymos—approximately 7 million miles away from Earth. 

“I loved seeing the footage of the spacecraft as it was approaching its impact with the asteroid,” science teacher Stuart Albaugh said. “I had always wondered what we would do if an asteroid that was large enough to cause harm was approaching the Earth, so it was cool to see how NASA was collecting data and doing missions to observe how specific collisions could alter the object’s course.”

Now that DART has successfully impacted Dimorphos, NASA plans to use ground-based telescopes to measure the extent to which DART shortened the asteroid’s orbit around Didymos—one of many objectives underpinning the project. The DART Investigation Team will also compare the results of the kinetic impact with existing computer simulations of kinetic impacts on asteroids. This will help evaluate the effectiveness of kinetic impact as a method to deflect Earth-bound asteroids, as well as evaluate how accurately current computer models reflect the behavior of real asteroids. 

According to the DART mission website, the DART mission boasted numerous advanced systems, such as DRACO, a narrow-angle telescope with a sophisticated on board image processor that streamed images of its target to Earth in live time. Moreover, SMART Nav, an autonomous optical navigation system, successfully identified and distinguished between Didymos and Dimorphos, and directed the spacecraft toward its target. Perhaps most notable was LICIACube, a cubesat provided by the Italian Space Agency, which deployed from the DART craft 15 days before impact to gather footage of the collision and the resulting ejecta cloud. 

“Talk about a bullseye. That responsive guidance system seems really intelligent and was obviously quite accurate,” science teacher Karl Kovacs said. “Thinking about those clear, digital pictures being sent back to Earth and then through the internet …wow. I watched a front end collision 7 million miles away.”

In addition to providing essential planetary defense information, DART also pioneered new technologies, such as NEXT-C, an ion propulsion system that offers improved performance and fuel efficiency over its predecessors. DART was also the first interplanetary spacecraft to fly the Roll-Out Solar Array (ROSA), a set of flexible and rollable solar panel “wings” that are initially compacted before and during lift-off but are then deployed once a spacecraft has left Earth. A small portion of ROSA was configured using Transformational Solar Array technology, which is three times more powerful than current arrays and could potentially reduce the cost of future missions to Jupiter and beyond. 

In 2024, the European Space Agency will independently launch the Hera mission, which will rendezvous with the Didymos system in late 2026 and conduct detailed surveys of both asteroids. In particular, the spacecraft and its two companion cubesats will focus on the impact left on Dimorphos by DART, as well as a precise determination of the mass of the asteroid. Both the DART and Hera missions, as well as the Italian LICIACube team, comprise the Asteroid Impact and Deflection Assessment (AIDA), an international collaboration among planetary defense researchers that aims to extract the best possible information for planetary defense of Earth.

DART was the first mission flown by NASA’s Planetary Defense Coordination Office (PDCO), an office established in 2016 focused on protecting Earth from Near-Earth objects (NEOs) such as asteroids and comets. According to NASA’s website, the PDCO aims to provide early detection of NEOs that could potentially damage Earth’s surface through a variety of ground and space based telescopes, as well as develop strategies for mitigating NEO impacts in conjunction with the US government. In particular, the PDCO aims to find, track, and characterize 90 percent of the predicted number of NEOs that exceed 140 meters in size, which are thought to pose the greatest danger to Earth—currently, only 40 percent of such objects have been identified. 

“I always feel that space exploration should be a larger focus in the news, as it truly is fascinating information and really helps put our problems into perspective,” Mr. Albaugh said. “A large portion of what space agencies explore is not just out of our planet, but also directly related to our Earth and our climate.”