NASA's DART spacecraft deliberately hit the small moonlet Dimorphos on 26 September 2022 to test whether a kinetic impact can change an asteroid's orbit. Click "Fire DART" below to replay the impact and watch Dimorphos's orbit around Didymos speed up to the real measured value.
Published figures (NASA/JHU Applied Physics Laboratory DART mission; peer-reviewed orbit result in Nature, 2023): DART hit Dimorphos on 26 September 2022 at 23:14 UTC at about 6.14 km/s (about 22,530 km/h), with a spacecraft mass at impact of about 579 kg. Dimorphos's orbital period around its larger companion Didymos (diameter about 780 m; Dimorphos about 160 m) shortened from 11 hours 55 minutes to about 11 hours 22 minutes - a change of 33 ± 1 minutes, more than 25 times NASA's minimum-success threshold of 73 seconds.
Click "Fire DART" to watch the probe fly in and hit Dimorphos, then see the orbit speed up to the real post-impact period. Drag to orbit the camera and scroll or pinch to zoom.
DART Asteroid Deflection 3D Explorer
This browser explorer replays NASA's real DART kinetic-impact test on the asteroid moonlet Dimorphos. Click "Fire DART" to watch the probe fly in and hit Dimorphos, then see its orbit around Didymos speed up by the real measured amount.
On 26 September 2022 at 23:14 UTC, NASA's DART spacecraft deliberately crashed into Dimorphos, the small moonlet of the binary asteroid Didymos, at about 6.14 km/s. It was the first full-scale test of whether a spacecraft can nudge a hazardous asteroid off course by simple kinetic impact - no explosives, just momentum. Neither Didymos nor Dimorphos was ever a threat to Earth; the pair was chosen specifically because a deflection test there carries zero risk.
- Click "Fire DART" to replay the impact and watch the probe hit Dimorphos
- Watch Dimorphos's orbit around Didymos speed up to the real post-impact period
- Read the live before/after facts panel, including the exact minute change measured by NASA
- Click "Reset" to return to the pre-impact state and replay the impact again
- Drag to orbit the camera around the binary system, scroll or pinch to zoom
- Runs fully in the browser with the vendored three.js engine - no account, no upload
| Fact | Value |
|---|---|
| Impact date/time | 26 September 2022, 23:14 UTC |
| DART spacecraft mass at impact | about 579 kg |
| Impact speed | about 6.14 km/s (about 22,530 km/h) |
| Distance from Earth at impact | about 11 million km |
| Didymos diameter | about 780 m |
| Dimorphos diameter | about 160 m |
| Dimorphos orbital period before impact | 11 hours 55 minutes |
| Dimorphos orbital period after impact | about 11 hours 22 minutes (-33 minutes) |
| NASA's minimum-success threshold | 73 seconds - DART exceeded it by more than 25 times |
These figures come from NASA and the Johns Hopkins Applied Physics Laboratory, which led the DART mission, and from the peer-reviewed orbital result published in Nature (Thomas et al., 2023). Follow-up observations also found Dimorphos's shape changed from a relatively symmetric oblate spheroid into a more irregular three-axis shape, and its orbit became measurably less circular - both consistent with a real, forceful impact rather than a gentle nudge.
This page focuses on the deflection TEST itself - the deliberate impact and its measured before/after result. For a real predicted near-miss with no impact, see Apophis 2029 Flyby 3D Explorer. For an object that actually reached the ground, see Chelyabinsk Meteor 3D Explorer. For the slow, passive drift that thermal re-emission causes on a spinning asteroid over years, see Yarkovsky Effect 3D Explorer.
Everything renders on your device with WebGL. The 3D engine loads once (about 0.7 MB) and is cached.
This is an educational approximation, not an orbital simulation: Didymos and Dimorphos are drawn closer together, relative to their own sizes, than their true separation so both stay visible on screen, and the DART probe's inbound flight is a short straight-line animation timed for clarity rather than the real multi-month cruise. The before/after ORBITAL SPEED CHANGE is not arbitrary, though - it is scaled directly from the real published period-change ratio (33 minutes shorter out of an 11-hour-55-minute period), so the relative speed-up you see matches the real measured result even though the animation itself runs much faster than real time.
Frequently Asked Questions
What did NASA's DART mission actually do?
On 26 September 2022, NASA's DART spacecraft deliberately crashed into Dimorphos, the small moonlet of the binary asteroid Didymos, at about 6.14 km/s to test whether a kinetic impact can change an asteroid's orbit.
Did DART actually change the asteroid's orbit?
Yes. Dimorphos's orbital period around Didymos shortened from 11 hours 55 minutes to about 11 hours 22 minutes - a change of 33 ± 1 minutes, more than 25 times NASA's minimum-success threshold of 73 seconds.
Was Didymos or Dimorphos ever a threat to Earth?
No. Neither asteroid posed any impact risk before or after the DART test. The pair was chosen specifically because a deflection test there carries zero risk to Earth.
How big is DART compared to the asteroid it hit?
The DART spacecraft had a mass of about 579 kg at impact - tiny next to Dimorphos, which is about 160 m across. The result shows that a small, fast-moving spacecraft can still measurably shift a much larger body's orbit.
Is the orbit and impact shown here a real physics simulation?
No. This page is an educational approximation: the bodies are drawn closer together than their true separation so both stay visible, and the probe's inbound flight is a short animation for clarity. The before/after orbital speed change is scaled from the real published period-change ratio, so the relative speed-up matches the measured result.
Where do these numbers come from?
NASA and the Johns Hopkins Applied Physics Laboratory, which led the DART mission, and the peer-reviewed orbital-period-change result published in Nature (Thomas et al., 2023).