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geosynchronous lunar orbit is basically just a satellite sitting at the same distance from the earth. It's so far away from the moon that it's basically pointle

by hueving 11y ago

geosynchronous lunar orbit is basically just a satellite sitting at the same distance from the earth. It's so far away from the moon that it's basically pointless to put something there unless your are observing the surface of the moon. https://en.wikipedia.org/wiki/File:L4_diagram.svg https://en.wikipedia.org/wiki/File:L4_diagram.svg

paulmd 11y ago
It's actually not, the L4 Lagrange orbit is something totally different from a typical satellite geosynchronous orbit. Consider the following link. http://freemars.org/l5/aboutl5.html http://freemars.org/l5/aboutl5.html Just intuitively - think about the rockets you need to get a satellite level payload to geosynchronous orbit vs what it took to get space probes to lunar orbit (let alone exolunar or returning a craft to earth). Bear in mind that staging is an exponential problem, the more mass and the more total delta-V you need, the problem gets exponentially worse. Small satellites can be launched what amounts to a SRBM and a small kicker, to get even a small probe to lunar orbit you need an ICBM plus a pretty decent kicker to handle translunar injection and lunar orbiting. To get a spacecraft there you need, well, a Saturn-V plus a decent kicker plus a small rocket for everything else. Geosynchronous satellites started in 1963 (Syncom 1) but the Lunar Orbiter program didn't start until 1965. That doesn't make sense if geosynchronous orbit was beyond lunar orbit. And if geosynchronous orbit was an equal distance, it would be trivial to put satellites into trailing orbits and cover the lunar blind spot. Lagrange points are a different (but very useful) orbital equilibrium. Particularly the Sun-Earth LaGrange points - these are indeed very far from Earth and have a very useful vantage point for all sorts of things. So far it's mostly been used for things like solar observatories.
- hueving 11y ago
  Thanks for the info, but I wasn't talking about geosynchronous orbits. I was talking about the term the GC used: 'geosynchronous lunar orbits'. i.e. an orbit synchronous to the rotation of the moon.

by hueving 11y ago

paulmd 11y ago

It's actually not, the L4 Lagrange orbit is something totally different from a typical satellite geosynchronous orbit. Consider the following link. http://freemars.org/l5/aboutl5.html http://freemars.org/l5/aboutl5.html Just intuitively - think about the rockets you need to get a satellite level payload to geosynchronous orbit vs what it took to get space probes to lunar orbit (let alone exolunar or returning a craft to earth). Bear in mind that staging is an exponential problem, the more mass and the more total delta-V you need, the problem gets exponentially worse. Small satellites can be launched what amounts to a SRBM and a small kicker, to get even a small probe to lunar orbit you need an ICBM plus a pretty decent kicker to handle translunar injection and lunar orbiting. To get a spacecraft there you need, well, a Saturn-V plus a decent kicker plus a small rocket for everything else. Geosynchronous satellites started in 1963 (Syncom 1) but the Lunar Orbiter program didn't start until 1965. That doesn't make sense if geosynchronous orbit was beyond lunar orbit. And if geosynchronous orbit was an equal distance, it would be trivial to put satellites into trailing orbits and cover the lunar blind spot. Lagrange points are a different (but very useful) orbital equilibrium. Particularly the Sun-Earth LaGrange points - these are indeed very far from Earth and have a very useful vantage point for all sorts of things. So far it's mostly been used for things like solar observatories.

hueving 11y ago
Thanks for the info, but I wasn't talking about geosynchronous orbits. I was talking about the term the GC used: 'geosynchronous lunar orbits'. i.e. an orbit synchronous to the rotation of the moon.