Re:Greg Robinson fixed NASA’s James Webb Space Telescope, re...
by jmyeet on Saturday July 16, 2022 @05:05AM
(#32116346)
The other 4 Earth Lagrange points are unsuitable for various reasons:
L1: between the Sun and the Earth. The Sun reflecting off the Earth would interfere with instruments.
L3: This is suitable for positioning but impractical because of distance from a communication and perspective.
L4 & L5: these are unsuitable because they're stable. Distance is an issue too. Why are stable Lagrange points unsuitable? Because things tend to collect there. Over the eons a whole bunch of crap has built up there and will continue to do so. That's not what you want when dealing with sensitive instuments.
Now you could say that you could orbit L4 or L5 like JWST orbits L2 and that's true but you still expend energy for stationkeeping. At L2 you spend energy to stay around the L2 point. At L4 and L5 you spend energy to avoid falling into the Lagrange point.
According to [1][2] it's more expensive (in delta-V terms) to get to L4/L5 than L2 but not hugely so.
L1: between the Sun and the Earth. The Sun reflecting off the Earth would interfere with instruments.
L3: This is suitable for positioning but impractical because of distance from a communication and perspective.
L4 & L5: these are unsuitable because they're stable. Distance is an issue too. Why are stable Lagrange points unsuitable? Because things tend to collect there. Over the eons a whole bunch of crap has built up there and will continue to do so. That's not what you want when dealing with sensitive instuments.
Now you could say that you could orbit L4 or L5 like JWST orbits L2 and that's true but you still expend energy for stationkeeping. At L2 you spend energy to stay around the L2 point. At L4 and L5 you spend energy to avoid falling into the Lagrange point.
According to [1][2] it's more expensive (in delta-V terms) to get to L4/L5 than L2 but not hugely so.
[1]: https://space.stackexchange.com/questions/27010/how-does-the...
[2]: https://space.stackexchange.com/questions/57463/what-is-the-...