High contrast image of of ejecta streaming from Dimorphos. Taken by LICIACube, the first Italian autonomous spacecraft in deep space.

DART on target: for the first time humans have changed the orbit of a celestial body using a kinetic energy transfer, like something from a sci-fi movie.

On September 26, NASA executed the final stage of the Double Asteroid Redirection Test (DART), when a spacecraft intentionally crashed into the asteroid Dimorphos at 15,000 mph to investigate whether such an impact could deflect an Earth-bound space object. A successful collision was the first cause for celebration, but now there’s even more reason to cheer.

NASA has officially determined the DART mission a success, revealing in a press conference that Dimorphos’ orbit has changed significantly. For mission success, DART needed to change Dimorphos’ nearly 12-hour orbital period around Didymos by at least 73 seconds. After two weeks of observations, the team revealed a 32-minute change in Dimorphos’ orbital period — more than 25 times longer than the benchmark for success. This is more than enough to change the course of a similar object if it were headed towards Earth.

The investigation team is still acquiring data with ground-based observatories around the world – from Mauna Kea Hawaii to the Chilean desert. As well as radar facilities at NASA Jet Propulsion Laboratory’s Goldstone planetary radar in California and the National Science Foundation’s Green Bank Observatory in West Virginia. They are updating the period measurement to improve its precision.

The trail of debris from the Dimorphos impact as seen by Hubble. The artificially created tail stretches for about 10,000 kilometers.
A gif showing how scientists monitor the moonlet’s orbit by measuring brightness changes
A few planetary defense concepts, from painting the object to exploding it
Possible asteroid defense system using interceptor satellites waiting near Earth

We’re still a ways from being able to divert a potentially dangerous asteroid, but now we know that a robot spacecraft could possibly do the job. With current technology. Focus now is shifting toward measuring the efficiency of energy transfer from DART to the asteroid.

“All of us have a responsibility to protect our home planet. After all, it’s the only one we have,” said NASA Administrator Bill Nelson. “This mission shows that NASA is trying to be ready for whatever the universe throws at us.”

Dimorphos never posed a threat to Earth, it is simply an easy to track object of the right size for experiments. In the case of a real near-earth asteroid, there would be multiple missions to make sure at least one worked, and sent years in advance, if possible.

Here’s NASA’s site for the mission.


David Raiklen
David Raiklen

David Raiklen wrote, directed and scored his first film at age 9. He began studying keyboard and composing at age 5. He attended, then taught at UCLA, USC and CalArts. Among his teachers are John Williams and Mel Powel.
He has worked for Fox, Disney and Sprint. David has received numerous awards for his work, including the 2004 American Music Center Award. Dr. Raiklen has composed music and sound design for theater (Death and the Maiden), dance (Russian Ballet), television (Sing Me a Story), cell phone (Spacey Movie), museums (Museum of Tolerance), concert (Violin Sonata ), and film (Appalachian Trail).
His compositions have been performed at the Hollywood Bowl and the first Disney Hall. David Raiken is also host of a successful radio program, Classical Fan Club.