NASA is about to crash into an asteroid

In a few days, the DART spacecraft will crash into an asteroid the size of the Great Pyramid of Giza in an attempt to alter its trajectory. The project, which incorporates NASA’s planetary defense program, aims to test whether the method could be used in the event of a programmed collision of an asteroid with Earth.

Straight into the wall

Launched in November 2021 from a SpaceX Falcon 9 rocket, DART targets a pair of asteroids made up of a main rock 800 meters wide, around which a small asteroid around 140 meters wide revolves. Its objective will be to crash into the latter at more than 24,000 km/h in an attempt to modify its orbit around the largest asteroid. The impact will take place on the night of September 26 to 27 next to near eleven million kilometers of the earth.

To measure the craft’s impact, scientists at Johns Hopkins University’s Applied Physics Laboratory will examine how long it takes the small moon to complete one lap around its parent asteroid, before and after impact. If the mission is successful, the team expects the small asteroid to complete its orbit in a shorter delay. To make sure, the researchers will use the Lowell Discovery telescope in Flagstaff, Arizona.

Several observation campaigns will also be carried out over the next few days to apprehend this binary system with precision. ” The before and after nature of this experiment requires in-depth knowledge of the asteroid system before we do anything about it.“, notes Lowell Observatory astronomer Nick Moskovitz. ” We want to be sure that any change we see is entirely due to DART“.

In other words, before the impact, the researchers will have to be sure that the orbit has been modified by the impact itself, and not by other factors. Sunlight could, for example, heat one side of the asteroid and thus slightly modify its trajectory. If this is the case, the data collected after the impact would be distorted.

This illustration shows the possible shapes the asteroid could take on impact. Credits: Martin Jutzi

A preemptive strike

To assess the consequences of this mission, a small CubeSat developed by the Italian space agency will also photograph the event by detaching from the spacecraft a few days before impact. Another spacecraft named Hera, developed by ESA, will take care of mapping the surface of the asteroid hit in four years, after the dust has dissipated.

NASA hopes DART will help it assess the effectiveness of hard-hitting spacecraft against potentially dangerous asteroids. Ultimately, this data could also help develop a possible future mission to deflect an asteroid on a collision course with Earth.

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