At 01:04 on the night of Monday, September 26 to Tuesday, September 27, a 550 kg probe designed by NASA will collide with the miniasteroid Dimorphos (160 m all the same) that orbits its older brother Didymos. The impact at 6 km/s will be observed by a minisatellite and broadcast live by NASA websites (Y he has them). The first large-scale planetary defense exercise will have taken place.
To verify that Dimorphos’s orbital velocity has indeed changed and to study the impact, a European probe, Hera, it should arrive at the site in 2026.
there is no danger
“In any case, there is no danger for the Earth”, reassured patrick michaelof’Observatory of the Côte d’Azur, Wednesday September 21 at a conference at the International Astronautical Congress. The researcher is part of the team that will interpret the data from the Dart mission (for the Double Asteroid Redirection Test).
“We have not yet found solutions to destroy asteroids. Diverting them is easier. But we don’t know the structure of Dimorphos. What we learned is that asteroids can have very heterogeneous structures, we don’t know if, at the point of impact, Dimorphos will behave like a sponge or like a very hard rock. »
Modify the orbital cycle
The objective, still modest, is to modify in at least 73 seconds the orbital cycle of Dimorphos (which takes 12 hours to revolve around its companion). “We have not identified any asteroids that pose a danger to Earth, assures Patrick Michel. But in the long term, humans will face this risk. We must have the means to deal with it. »