DART: ISAE-SUPAERO students publish new scientific results in Nature Communications

For the past 10 years, the SSPA (Space Systems for Planetary Applications) team at ISAE-SUPAERO has been actively collaborating on the DART and Hera missions, two planetary defence space missions led by NASA and ESA respectively.

Naomi Murdoch, a researcher in planetology at ISAE-SUPAERO, is involved in the scientific analysis and interpretation of DART data.

DART stands for Double Asteroid Redirection Test. Behind this acronym lies a full-scale planetary defence test developed by NASA and launched in 2021, the aim of which was to divert an asteroid from its trajectory. It culminated in September 2022 with the DART missile probe striking the Dimorphos moon of the Didymos asteroid to deflect it.

"This first attempt to deflect an asteroid was a success, with measurable effects on the orbit of Dimorphos", recalls Naomi Murdoch. It demonstrated the feasibility of modifying the trajectory of an asteroid in the context of planetary defence".

An active and involved research team

With the aim of gaining a better understanding of asteroid surfaces and their physical properties, her team at ISAE-SUPAERO, SSPA, is actively involved in the scientific analysis and interpretation of the DART data.

"Our objective is to understand the physical properties of the Dimorphos asteroid in order to better interpret the results of the DART impact", explains the planetary scientist.

Her team has just published several new results in the prestigious journal Nature Communications. Remarkably, two of the scientific articles were written by doctoral and Master in Aerospace Engineering students at ISAE-SUPAERO: PhD students Colas Robin and Alexia Duchêne, and Master in Aerospace Engineering students Jeanne Bigot and Pauline Lombardo.

A better understanding of the physical properties of asteroids

The first article focuses on estimating the mechanical properties of the moon Dimorphos, a key piece of information for understanding and modelling the DART impact. Colas Robin and Alexia Duchêne, both PhD students, studied the last complete image of Dimorphos captured by the DART probe before the impact and compared the boulders on its surface with images of other asteroids.

"The shape and size of boulders on the surface of planets can provide a wealth of information about the physical properties of these bodies, as well as their history", explains Alexia Duchêne, who has just received an ESPACE grant from the Fondation des Ailes de France.

The two PhD students have also developed and applied a method that can be used for all planetary space missions using a camera. "This will enable us to apply this technique to data from the Hera mission (read box below) and we will also use it on the surface of the Martian moon Phobos with Idefix® images", adds Colas Robin.

Their study has also shown that the boulders on Dimorphos were probably formed by one or more major impacts, helping to unravel the fascinating history of life in the binary asteroid system!

>> Article: The DOI number of Robin et al. will be 10.1038/s41467-024-50147-w

Estimating the bearing capacity of an asteroid surface

The second article, written by Jeanne Bigot and Pauline Lombardo, two students in ISAE-SUPAERO’s Master of Aerospace Engineering programme, looks at the geotechnical properties of the primary asteroid Didymos using DART images. The students worked for a year with Naomi Murdoch to assess the bearing capacity of the surface, a parameter that indicates whether an object or lander will remain on the surface or sink into it.

"This is the first time that the bearing capacity of the surface of an asteroid has been estimated", says Jeanne Bigot. "We have found that the surface of Didymos will collapse much more easily than the surface of the Moon if we hit it or land on it."

Their research has identified linear grooves on the surface of Didymos, running from the poles to the equator. These are tracks formed by boulders rolling across the surface of the asteroid. "We have combined our measurements of the boulder tracks with geotechnical engineering to determine the properties of the asteroid’s surface", continues Pauline Lombardo.

And the results show that the surface of Didymos is fragile, with a load-bearing capacity 1,000 times lower than that of the lunar highlands or dry sand on Earth. The higher resolution images from the Hera mission (read box below) will enable this analysis to be refined and will provide additional information on the traces of boulders on Didymos.

"We were able to be part of an international space mission team, which was a fantastic experience as a Masters student at ISAE-SUPAERO", enthuse the two students.

>> Article: The DOI number for Bigot, Lombardo et al. will be 10.1038/s41467-024-50149-8