orbital mechanics - Difference between Tundra and Molniya orbits ...
Jan 3, 2018 · As for main technical differences, Molniya requires three separate launches, but Tundra requires a stronger booster to reach the higher orbit. Also, Tundra's somewhat higher apogee may require stronger radio connection or result in worse results due to higher distance; the difference is not big though (about 15%).
artificial satellite - Why are Molniya orbits peculiar? - Space ...
Aug 18, 2015 · An additional advantage is that considerably less launch energy is needed to place a spacecraft into a Molniya orbit than into a geostationary orbit. Disadvantages are that, as opposed to a spacecraft in a geostationary orbit, the ground station needs a steerable antenna to track the spacecraft and that the spacecraft will pass the Van Allen ...
What are the advantages of a Molniya orbit over a tundra orbit?
Nov 26, 2018 · However, Molniya orbital periods are 1/2 day, while tundra orbits are geosynchronous orbits. Thus, every other Molniya orbit apogee is over an opposite part of the world, while tundra orbits are quite stationary in longitude. Russia's communication satellites occupy Molniya orbits.
orbital mechanics - Why should Molniya orbit period be a half …
Sep 4, 2016 · In the Wikipedia article for Molniya orbit the introduction mentions that the period should be 0.5 sidereal day, so that its path across the sky every ~12 hours as observed from a given point on Earth remains constant.
Are Molniya orbits used apart from Russian communication …
TWINS flies as a mission of opportunity on two high-inclination, high altitude spacecraft provided by a non-NASA US government organization. Each spacecraft is 3-axis stabilized and approximately nadir pointing, and is placed in a Molniya orbit with 63.4° inclination and 7.2 RE apogee, an ideal orbit for magnetospheric imaging.
Orbits that allows observation of a polar region
May 2, 2018 · A circular orbit of a certain height has the shortest period. An elliptical orbit with the same minimal distance has a longer period as the circular orbit. To get a shorter period a circular lower orbit may be used, but the decay of this orbit will be faster due to …
Has there been any satellites that used an 'upside-down' Molniya …
Feb 13, 2018 · Have there been any satellites that used an orbit similar to what Russia uses, but for the southern hemisphere? Specifically to service South America and Australia/Oceania?
orbit - Orbital altitudes, are some better than others and why?
Dec 26, 2014 · Some examples for interesting elliptic orbits are the Tundra and the Molniya orbit. Geosynchronous orbits obviously only work when placed above the equator. If you want to have a satellite stationary over very high latitudes, they don't work. So instead you use one of the two orbits. They are highly elliptical and have an inclination of ~63.4°.
How would one obtain the longitude of satellite at the apogee?
Dec 26, 2022 · Molniya orbits are designed to have satellites hang out most of the time at very northern latitudes, which means having the apogee at the point furthest away from the equatorial plane. Thus, the apogee of a Molniya orbit is 90 degrees ahead of the ascending node, so $\Omega + 90º$ in terms of the classical orbital elements.
How exactly did ground stations track the early Molniya satellites?
Sep 12, 2021 · To direct the antenna mirror to this or that point in space in the sky, the following system was needed: the coordinates of the Molniya satellite were transmitted to the Orbita station in time, with a shift every 0.7 °. The time between two points and the location of the satellite were known - the elevation angle, azimuth.