Tycho Magnetic Anomaly-1 (also known as TMA-1) is a fictional phenomenon in the movie 2001: A Space Odyssey and the book of the same name. TMA-1 refers to the apparent magnetic irregularity found at the Tycho crater on the moon surface by American astronauts. The anomaly is caused by an object buried 30 feet under the lunar surface; when exposed, it was found to be a black cuboid whose sides measured in the precise ratio 1:4:9 (1²:2²:3²).

An identical (except in size) object was found later, orbiting Jupiter (on a moon of Saturn in the book, although this was changed to Jupiter in the sequel book, 2010). This object was dubbed "TMA-2" even though it had no relationship to the Tycho crater and no magnetic field. By the year 3001, the first Monolith to be encountered by mankind's prehistoric evolutionary predecessors was found in Africa buried in ancient rock, and was retroactively dubbed "TMA-0".