The DART (Double Asteroid Redirection Test) was a test by NASA in 2022 to see if its spacecraft could collide with an asteroid to change its trajectory. The purpose of the mission was to see if this method could be used for planetary defense.  

At the moment, no asteroids pose a risk to the Earth over the next 100 years, but only 40% of them have been found! DART was the first demonstration of asteroid deflecting technology. There were other reasons as to why NASA decided to carry out this mission. One was to see how accurate the computer simulations approximating impacts with asteroids were. Another was for an investigation team to measure how much the impact changed the motion of the asteroid by using telescopes on Earth to track its motion. 

However, this move was brought about partially by the US Congress, who in 2005, among other targets, set NASA the goal of finding and cataloguing at least 90 percent of Near-Earth Objects (NEOs) which are asteroids that are 140m in diameter or larger and pass within 30 million miles of the Earth’s orbit, by 2020. This goal was not being met as outlined in a 2014 report, which highlighted NASA’s inability to provide adequate funding to their NEO program and the lack of structure within the group in charge.  

Thus, in 2016, the Planetary Defense Coordination Office (PDCO) was established by NASA to oversee planetary defense. Once NASA established the PDCO, it stated that the organization would oversee sponsoring studies of technologies that prevent NEOs from hitting the Earth. Some of the previous missions included OSIRIS-REx which obtained a sample of a Near-Earth asteroid and performed detailed analysis on it, and NEOWISE, which was a repurposed infrared space telescope now used to search for NEOs. 

DART spacecraft | The Planetary Society

The latest project was DART. This involved collaboration with the European Space Agency (ESA), who also planned to launch their own spacecraft, AIM. However, it was decided that the ESA would launch the spacecraft HERA four years after the DART mission was completed to investigate the impact the DART mission had on the asteroid’s trajectory. 

The 610kg DART spacecraft collided successfully with the asteroid Dimorphos on the 26th September 2022, which shortened Dimorphos’ orbit by around 32 minutes. Success was considered shortening its orbit by over 73 seconds. In 2026, the HERA spacecraft will measure how effective this planetary defense method is such as by analysing the debris cloud caused by the impact.

It is amazing to see we have the technology available to deflect asteroids, something only seen in movies before, made a reality.



Image of DART spacecraft from

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