DART changed an asteroid pair's orbit around the sun, study finds
Mar 6th 2026
New analysis of 22 stellar occultations shows NASA's 2022 DART impact not only shortened Dimorphos' orbit around Didymos but also produced a tiny slowdown in the pair's orbit around the sun, a first for human activity in space.
- DART deliberately crashed into moonlet Dimorphos in 2022 and shortened its 12 hour orbit around parent asteroid Didymos by about 32 minutes.
- A Science Advances report on March 6 shows the impact also slowed the Didymos–Dimorphos system's heliocentric motion by more than 10 micrometers per second, appearing as a 150 millisecond timing shift.
- Astronomers measured the tiny change using 22 stellar occultation observations taken from October 2022 to March 2025.
- Most of the mutual orbit change came from the direct impact, while ejecta that escaped the pair carried away extra momentum and altered their joint motion around the sun.
- This is the first confirmed case of human activity changing the orbit of a celestial object and strengthens knowledge for planetary defense.
- The European Space Agency's Hera mission is scheduled to arrive later this year to make direct follow up measurements.