Asteroid defense test confirms orbit change of a two-asteroid system

A study in Science Advances confirms NASA's 2022 DART mission altered the orbit of an entire two-asteroid system, measuring a center-of-mass speed change of about 11.7 microns per second. Researchers report that debris from the impact added momentum beyond the spacecraft's strike.

Scientists report that NASA's 2022 DART mission changed the orbit of a two-asteroid system, according to a study published in Science Advances. The 2022 mission sent a bus-sized spacecraft to collide with a 525-foot-wide asteroid that orbits a larger companion. Researchers had earlier confirmed the smaller body's path shifted; the new analysis shows the system's shared center of mass also changed. The measured change in the system's motion was small per second but grows over time. Key findings: - The study reports the DART impact altered the orbit of the entire two-asteroid system rather than only the struck body. - DART was about a 1,300-pound spacecraft that struck the 525-foot secondary at more than 14,000 miles per hour in 2022, as reported by mission scientists. - The system's center-of-mass speed changed by about 11.7 microns per second, which accumulates to roughly 0.2 miles over a year. - Debris (ejecta) from the collision contributed additional momentum beyond the spacecraft's direct impact. - The particular asteroid pair targeted in the test was not on a collision course with Earth. Summary: The study shows a kinetic impact can alter the orbit of a binary asteroid and that ejecta from the collision added measurable momentum to the system. This provides a measurable way to confirm whether a deflection attempt changed a hazardous object's path. Undetermined at this time.