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Tundra and Molniya orbits are used to provide high-latitude users with higher elevation angles than a geostationary orbit.This is desirable as broadcasting to these latitudes from a geostationary orbit (above the Earth's equator) requires considerable power due to the low elevation angles, and the extra distance and atmospheric attenuation that comes with it.
A highly elliptical orbit (HEO) is an elliptic orbit with high eccentricity, usually referring to one around Earth. Examples of inclined HEO orbits include Molniya orbits , named after the Molniya Soviet communication satellites which used them, and Tundra orbits .
For Earth this means a period of just under 12 hours at an altitude of approximately 20,200 km (12,544.2 miles) if the orbit is circular. [16] Molniya orbit: A semi-synchronous variation of a Tundra orbit. For Earth this means an orbital period of just under 12 hours. Such a satellite spends most of its time over two designated areas of the ...
The Tundra orbit is an eccentric geosynchronous orbit, which allows the satellite to spend most of its time dwelling over one high latitude location. It sits at an inclination of 63.4°, which is a frozen orbit, which reduces the need for stationkeeping. [23] At least two satellites are needed to provide continuous coverage over an area. [24]
A satellite with an orbital inclination between 90° and 180° (or, equivalently, between 0° and −90°) is said to be in a retrograde orbit. [note 2] A satellite in a direct orbit with an orbital period less than one day will tend to move from west to east along its ground track. This is called "apparent direct" motion.
The Arctic is rapidly changing from the climate crisis, with no "new normal," scientists warn. Wildfires and permafrost thaw are making the tundra emit more carbon than it absorbs. From beaver ...
From a circular orbit, thrust applied in a direction opposite to the satellite's motion changes the orbit to an elliptical one; the satellite will descend and reach the lowest orbital point (the periapse) at 180 degrees away from the firing point; then it will ascend back. The period of the resultant orbit will be less than that of the original ...
The tundra has become a source of emissions, rather than a carbon sink, the authors said. The Arctic is heating up far faster than places at lower altitudes as melting ice reflects less radiation ...