The binary nature of the asteroid was discovered by others; suspicions of binarity first arose in Goldstone delay-Doppler echoes, and these were confirmed with an optical lightcurve analysis, along with Arecibo radar imaging on 23 November 2003.

[14] Didymos spends 1/3 of its time orbiting in the near-Earth asteroid (NEA) region where impacts are more probable.

Over its median NEA lifetime of 8 to 10 million years, Didymos probably has been impacted tens of times.

[1] Subsequent visible and near-infrared spectroscopy showed it to be silicate in nature, which also qualifies it as a stony S-type asteroid.

[16] It rotates rapidly, with a period of 2.26 hours and a low brightness variation of 0.08 magnitude (U=3/3), which indicates that the body has a nearly spheroidal shape.

Appropriately, Dimorphos serves dual roles as both a test target and as a part of a blueprint for a modality for future planetary protection.

[18] The name of the moon was suggested by planetary scientist Kleomenis Tsiganis at the Aristotle University of Thessaloniki, Greece.

The NASA mission was intended to test whether a spacecraft impact could successfully deflect an asteroid on a collision course with Earth.

Didymos is the most easily reachable asteroid of its size from Earth, requiring a delta-v of only 5.1 km/s for a spacecraft to rendezvous, compared to 6.0 km/s to reach the Moon.