Glossary term: Apollo

Description: There are two meanings of the word Apollo in astronomy. The first refers to the Apollo program that put the first human beings on the surface of the Moon. These missions were mostly powered by the Saturn V rocket. In total there were fourteen numbered missions launched (Apollo 4–17); eleven missions were crewed with nine of these going to the Moon, of which six made lunar landings with the other three orbiting the Moon.

On the other hand, a group of near-Earth asteroids is also known as Apollo, named after the asteroid (1862) Apollo. This group of asteroids is characterized as having a semi-major axis greater than the Earth–Sun distance of one astronomical unit (AU) and with perihelion distances less than 1 AU. This means that during their orbits, Apollo asteroids move from inside the Earth's orbit to outside the Earth's orbit although these asteroids rarely come close to the Earth itself.

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Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".

Related Media

An astronaut in a white spacesuit stands on the grey lunar surface with a piece of equipment in-front of a lunar lander

Apollo 11 lunar activity

Caption: NASA astronaut Edwin 'Buzz' Aldrin installs a seismometer in front of the Apollo 11 Eagle lunar lander during an extravehicular activity (EVA) on the Moon. Neil Armstrong shot this photo during the first human mission to the surface of the Moon in 1969.
Credit: NASA/Project Apollo Archive credit link

License: PD Public Domain icons