Meteoroid vs Asteroid vs Meteorite vs Meteor
Meteoroid: A small rocky or metallic object in orbit around the Sun (or another star). A meteoroid which strikes the Earth (or other large body) is called a meteorite.
Asteroid: A rocky or metallic object, smaller than a planet but bigger than a meteoroid, that orbits the Sun or another star; also known as a minor planet.
Meteorite: A solid portion of a meteoroid that survives its fall to Earth, or to some other body.
Meteor: The light phenomenon, known popularly as a shooting star or falling star, that results from the entry into Earth’s atmosphere of a solid particle, or meteoroid, from space.
- The Worlds of David Darling
Micrometeorites
Micrometeoroid collected from the antarctic snow
A Micrometeoroid (also micrometeorite, micrometeor) is a tiny meteoroid; a small particle of rock from space, usually weighing less than a gram, that poses a threat to space exploration. The risk is especially high for objects in space for long periods of time, such as satellites. They also pose major engineering challenges in theoretical low-cost lift systems such as rotavators, space elevators, and orbital airships.
Micrometeoroids are extremely common in space, particularly near the Earth. Their velocities relative to a spacecraft
in orbit can be on the order of kilometers per second, and resistance
to micrometeoroid impact is a significant design challenge for
spacecraft designers.
Micrometeoroids are very small, typically metallic, pieces of rock
broken off from larger chunks of rock and debris. They often date back
to the formation of the solar system.
Since orbital velocities are so high, and since they can enter an earth
orbit from any angle, micrometeoroids in earth orbit constantly
intercept the orbits of spacecraft and impact them at high speed. While
their tiny size limits the damage incurred, the high velocity
constantly degrades the outer casing of spacecraft and, in the long
term, can threaten the functionality of systems.
Micrometeoroids can also be easily found on earth in places where rainwater
can concentrate them (such as a drain spout of roof gutters). Since
metallic dust occurs relatively rarely on earth from other sources,
metallic micrometeoroids can typically be separated from Earth dust via a strong magnet. Micrometeoroids comprise most of the 30,000 tons of space debris that are deposited on Earth every year.
Impacts by small objects with extremely high velocity are a current area of research in terminal ballistics. Accelerating objects up to such velocities is difficult; current techniques include linear motors and shaped charges.
In order to understand the micrometeoroid population better, a number of spacecraft (including Lunar Orbiter 1, Luna 3 and Mars 1) include micrometeoroid detectors.
This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia Encyclopedia article "Micrometeoroid"
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