User:Nrco0e/Notes/Dimorphos

Dimorphos (formal designation (65803) Didymos I; provisional designation S/2003 (65803) 1) is a small, 150 m diameter moon of the near-Earth asteroid 65803 Didymos, with which it forms a binary system. Discovered on 20 November 2003 by Petr Pravec and collaborators, Dimorphos was the target of NASA's Double Asteroid Redirection Test (DART) mission, which deliberately collided a spacecraft with the moon on 26 September 2022 to alter its orbit around Didymos. Around the same time, the Italian Space Agency's LICIACube spacecraft flew by Dimorphos to image the DART impact. The impact reduced Dimorphos's orbital period by 33 minutes and ejected over 10 e6kg of dusty debris into space, which produced an expanding dust plume and a 70000 km-long tail of dust swept away by solar radiation pressure.

Before DART impacted Dimorphos, the moon had an oblate spheroid shape with a surface covered in boulders and few small craters. The surface features of Dimorphos suggest that the moon is a weakly-held rubble pile that formed less than 300,000 years ago, as a result of Didymos shedding its mass by its rapid rotation. Computer simulations and telescopic observations by researchers indicate that, as a result of Dimorphos's rubble pile structure, the DART impact globally resurfaced Dimorphos and deformed its shape into an elongated ellipsoid, rather than creating an impact crater. Simulations and observations also suggest that the DART impact caused Dimorphos's rotation to begin tumbling chaotically. The European Space Agency's Hera mission is planned to arrive at the Didymos system in 2026 to further study the effects of DART's impact on Dimorphos.

Discovery
Eclipsing binary lightcurve, radar

Name
Designation, name

Planning
DART mission was selected in 2015, planetary defense goals

Geology
Five boulders (saxa) and six craters have been given names of traditional drums from several cultures. They are approximately 10 meters across or smaller: