Polar orbit
A polar orbit is one in which a
Launching satellites into polar orbit requires a larger launch vehicle to launch a given payload to a given altitude than for a near-equatorial orbit at the same altitude, because it cannot take advantage of the Earth's rotational velocity. Depending on the location of the launch site and the inclination of the polar orbit, the launch vehicle may lose up to 460 m/s of Delta-v, approximately 5% of the Delta-v required to attain Low Earth orbit.
Usage
Polar orbits are used for Earth-mapping, reconnaissance satellites, as well as for some weather satellites.[2] The Iridium satellite constellation uses a polar orbit to provide telecommunications services.
Near-polar orbiting satellites commonly choose a
To retain a Sun-synchronous orbit as the Earth revolves around the Sun during the year, the orbit must precess about the Earth at the same rate (which is not possible if the satellite passes directly over the pole). Because of Earth's equatorial bulge, an orbit inclined at a slight angle is subject to a torque, which causes precession. An angle of about 8° from the pole produces the desired precession in a 100-minute orbit.[3]
See also
- List of orbits
- Molniya orbit
- Tundra orbit
- Vandenberg Air Force Base, a major United States launch location for polar orbits
References
- ^ "ESA - Types of Orbits". 2020-03-30. Retrieved 2021-01-10.
- ^ Science Focus 2nd Edition 2, pg. 297
- ^ a b Stern, David P. (2001-11-25). "Polar Orbiting Satellites". Retrieved 2009-01-21.
External links
- Orbital Mechanics (Rocket and Space Technology)