SafekipediaA Tundra orbit (Russian: орбита «Тундра») is a special way for satellites to move around the Earth. It is a highly elliptical path that matches the Earth’s rotation, called a geosynchronous orbit. This orbit has a high tilt, called inclination, of about 63.4°, and it takes exactly one sidereal day (about 24 hours) to complete a full circle around the planet. Satellites in this orbit spend most of their time over one particular area, which is very useful for sending messages and information to places far north or south, where regular satellites have trouble reaching.
The Tundra orbit was created by scientists in the former Soviet Union. It was developed after another special orbit called the Molniya orbit, which was made in the 1960s to help areas near the poles get better communication. The Tundra orbit is similar but designed so that a satellite can stay above one region for a long time, giving constant coverage to that spot. Both orbits were important because they helped solve communication problems caused by the Soviet Union’s large size and its position on the Earth.
One special feature of a Tundra orbit is the path that the satellite appears to take when viewed from the Earth. This path, called the ground track, makes a figure-eight shape, with a smaller loop either over the northern or southern half of the planet. This is different from the Molniya orbit, which also serves high-latitude areas but moves more quickly and does not stay over one place as long. These orbits show how clever engineering can help connect distant parts of our world.
Uses
Tundra and Molniya orbits help send signals to places far north or south on Earth. From a regular geostationary orbit, which stays above the equator, it’s hard to send strong signals to these areas because they are far away and the signal has to go through more air. In very far north places, regular satellites can’t even be seen at all.
Tundra orbits let satellites spend a lot of time over these faraway places, which makes communication easier. But it costs more because you need two satellites to keep the signal going all the time. Also, satellites in Tundra orbits don’t have to go through dangerous areas around Earth called the Van Allen belts, which is an advantage over Molniya orbits.
Properties
A Tundra orbit is a special path around Earth used for satellites. It has an angle, called inclination, of 63.4° and a period of 1436 minutes. This orbit is very stretched out, with an eccentricity between 0.24 and 0.4, and a distance from Earth’s center, called semi-major axis, of about 42,164 km.
The Tundra orbit is designed so that satellites spend most of their time over certain areas of Earth, especially near the poles. This makes them useful for communication in places far from the equator. By choosing the right angle and shape for the orbit, the satellite’s path stays the same over time without needing frequent adjustments.
oblateness · argument of perigee · frozen orbit · geostationary orbit
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Spacecraft using Tundra orbits
Russia uses satellites in Tundra orbits for its EKS (Edinaya Kosmicheskaya Sistema) or Kupol system. These satellites help detect and track missile launches to give early warnings.
From 2000 to 2016, Sirius Satellite Radio used three satellites in Tundra orbits. This helped improve radio service in northern areas. After merging with XM, the system changed to use different orbits instead. The Quasi-Zenith Satellite System in Japan uses a similar orbit to serve better positioning in Japan.
Images
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