DART: NASA’s Mission to Deflect an Asteroid
Asteroids around a star, artist impression. Credit: NASA

DART: NASA’s Mission to Deflect an Asteroid

23/11/2021Written by Catherine Muller

The DART spacecraft will aim to alter the path of an asteroid, a technique that could be used to prevent hazardous objects hitting Earth in the future.

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Illustration of the DART spacecraft. Credit: NASA

We’ve all heard the unfortunate story of the dinosaurs. The creatures that dominated planet Earth before they were made extinct by an asteroid impact, one they were powerless to stop. To avoid the same fate for humankind, NASA has been developing the Double Asteroid Redirection Test (DART) mission.

Set to launch on 24 November, the DART spacecraft will aim to alter the path of an asteroid, a technique that could be used to prevent hazardous objects hitting Earth in the future. Scientists hope to achieve this by colliding DART with an asteroid named Dimorphos. But don’t worry, Dimorphos does not actually present a threat to Earth.

Mission Overview and Aims

Mission Overview and Aims
DART Mission Patch. Credit: NASA

At 06:20 GMT, DART will be launched from the Vandenberg Space Force Base in California. Hitching its ride into space on board a SpaceX Falcon 9 rocket, DART will travel 11 million kilometres to its target asteroid, the 65803 Didymos system.

This system is comprised of two asteroids, Didymos and Dimorphos. The smaller of the two, Dimorphos, makes a complete orbit around its companion Didymos every 11.93 hours.

It is Dimorphos that is NASA’s target for the mission. DART is fitted with an onboard camera and navigation software that will allow for a head on collision with Dimorphos in late September 2022. This collision is the primary objective of the mission, but other objectives include:

  • Altering the time taken for Dimorphos to orbit Didymos (its orbital period).
  • Measuring how much this orbital period changes using ground-based telescopes.
  • Studying ejecta and Dimorphos’ surface post collision

Why Dimorphos?

Why Dimorphos?
Simulated image of the Didymos system. Dimorphos (left) and Didymos (right). Credit: NASA

Discovered in 2003, Dimorphos is a small asteroid, at just 160m in size. So why is this unlucky asteroid the target of NASA’s experimentation?

Well, Dimorphos is close enough to Earth that we can observe its trajectory from the ground, necessary for determining the impacts of its collision with DART. Additionally, Dimorphos is thought to be the type of object that could be a serious threat should it stray too close to Earth. Scientists are confident, however, that this asteroid is no danger to our planet, and any material ejected from the collision will not come near us either.

Asteroid Deflection

Asteroid Deflection
Illustration of how DART's impact will alter the orbit of Dimorphos. Credit: NASA/Johns Hopkins

The method of asteroid deflection being tested by the DART mission is known as kinetic impact. The spacecraft is roughly the size of a small car and will weigh approximately 550 kgTravelling at 6.6 km/s, it is estimated that that the collision should alter the orbital period of Dimorphos by several minutes, which telescopes on Earth should be able to detect within a week.

In addition to this ground-based observation, the Light Italian Cubesat for Imaging of Asteroids (LICIACube) will be brought along to make additional observations. LICIACube is a small Cubesat, a miniature satellite that will be released from DART 10 days before the collision. Its proximity to the asteroids will enable detailed observations to be made of the collision site and resulting debris. With all this studying, scientists hope to determine whether kinetic impact would be a feasible method of asteroid deflection in the future should it be needed.


Illustration of NASA’s DART spacecraft and the Italian Space Agency’s LICIACube at the Didymos binary system. Credit: NASA/Johns Hopkins, APL/Steve Gribben

DART forms half of the Asteroid Impact and Deflection Assessment (AIDA) project, a collaboration between NASA and ESA. This partnership acknowledges the necessity of international collaboration when tackling global issues such as an impending asteroid impact. The information gathered from the DART mission will give us an idea of whether we are able to redirect the paths of asteroids. If the project is successful, this could be a big step forward in the development of deflection technology. Hopefully this will keep us all a bit safer on Earth, and we might be able to sleep a little bit tighter, knowing we will not meet the same fate as the dinosaurs.

If you are interested in watching the launch of DART on 24 November, it can be watched live on NASA’s YouTube channel and other social media platforms.  


About the author: Catherine Muller is a Space Communications Presenter at the National Space Centre.