Short answers, pulled from the story.
Asaph Hall III discovered the moon Deimos on the 12th of August 1877 while working at the United States Naval Observatory in Washington, D.C. He spotted the object at about 07:48 UTC that morning after searching specifically for Martian moons.
The name came from a suggestion by academic Henry Madan who drew inspiration from Book XV of the Iliad where Ares summons Dread and Fear. These figures correspond to the Greek names Deimos and Phobos as described in classical literature.
Deimos measures approximately 15 kilometers across its longest dimension and appears gray with highly non-spherical triaxial dimensions. It is about 57% the size of Phobos and has an escape velocity reaching just 5.6 meters per second.
Only two features bear official names on Deimos including Crater Swift which spans one kilometer in diameter and Voltaire measuring 1.9 kilometers wide. Both received approval in 1973 by international astronomical authorities based on literary figures Jonathan Swift and Voltaire.
Mars rover Opportunity photographed Deimos crossing the Sun on the 4th of March 2004 while Spirit captured another transit event thirteen days later on the 13th of March 2004. The moon appears as a small black dot against the bright disk during these rare visual events.
JAXA plans to launch the MMX mission in October 2026 which includes flybys of both moons and sample return from Phobos. ESA's Hera spacecraft approached within 300 kilometers in March 2025 and Aladdin was selected as a finalist in NASA Discovery Program during 1997.