Asteroid planetary defence results published

Results show what happened to the spacecraft and asteroid following NASA’s asteroid deflection mission.

On 26 September 2022 NASA deliberately crashed a spacecraft into an asteroid, as the first ever experimental test of ‘planetary defence’ technology. The aim of the Double Asteroid Redirection Test (DART) mission was to change the trajectory of a harmless asteroid, to prove that we could do so in case we ever find one heading towards Earth. The first scientific results from this mission have now been published by the journal Nature. These include a collection of papers which  describe what happened to the spacecraft and asteroid, what was seen by the small ‘LICIACube’ satellite that accompanied DART to witness the collision, and what was seen from Earth by astronomers using telescopes. Researchers from the University of Edinburgh’s Institute for Astronomy were part of the team that observed the impact, using telescopes in Chile and in Kenya, and the Hubble Space Telescope.

Dr Agata Rożek, Prof Colin Snodgrass, and Dr Mariangela Bonavita worked on observations of the system before and after impact using the 1.54m Danish telescope at the La Silla observatory in Chile. The paper led by Dr Cristina Thomas, of Northern Arizona University, combines these measurements with others from telescopes elsewhere in Chile and the USA to show that the impact shortened the orbital period of the asteroid system by 33 min, well in excess of the minimum goal of the mission.

Prof Colin Snodgrass, Brian Murphy, and Dr Cyrielle Opitom were part of a study of the cloud of debris produced after the impact, as observed by the Hubble Space Telescope. The study, led by Dr Jian-Yang Li of the Planetary Science Institute, used observations of the debris in the hours and days following the impact to estimate the size and amount of particles ejected by the impact, and how their interaction with the binary asteroid system led to the formation of the complicated looking ‘tail’. 

This first wave of scientific papers show that the DART mission was highly successful, and also give us glimpses of the rich variety of new information about asteroids that will come from further analysis of the data. In the coming months more detailed studies will look at different aspects of the physics of the collision, what we saw at the moment of impact, and the longer term evolution of the comet-like tail that was created. These will include studies led by Edinburgh astronomers using the world-leading Very Large Telescope in Chile, and results from Edinburgh’s own unique contribution to the project: a small observatory set up at a remote site in Kenya, which was positioned there to have a direct view of the collision.

Prof Colin Snodgrass from the Institute for Astronomy commented:

The impact of the DART spacecraft on asteroid Dimorphos lasted only a fraction of a second but the impact this will have on the study of asteroids will be felt for years. There are many more exciting results to come.

Further information about the project

The Johns Hopkins Applied Physics Laboratory built and operated the DART spacecraft and manages the DART mission for NASA’s Planetary Defense Coordination Office as a project of the agency’s Planetary Missions Program Office. LICIACube is a project of the Italian Space Agency (ASI), carried out by Argotec.

Neither Dimorphos nor Didymos poses any hazard to Earth before or after DART’s controlled collision with Dimorphos.