Eli5 – How do probes at Lagrange points not drift in their orbits?

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Context I was watching a video about the JWST and saw that it orbited the sun at the L2 point, but that got me wondering as to how it doesn’t slowly drift in its orbit, considering its at a higher (but presumably at a similar eccentricity to that of the earths) orbit. Are higher orbits not always slower?

Basically how does the JWST not fall behind the earth, for lack of better phrasing.

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3 Answers

Anonymous 0 Comments

ohhh, it’s been a good day for ELI5.

First of all, a stationary L2 is a bit different than an orbital L2. Since you’re just asking about the stationary, it’s pretty simple. That’s just the point where the earth is tugging on it as hard as the sun is tugging on it.

It’s not quite an orbit, more like it’s just the point where it’s falling into the earth at the same speed it wants to fall into the sun. Of course the earth orbits the sun, so it has to follow at the same speed to keep those distances equal.

This isn’t quite as stable as a normal orbit, so it needs to make course corrections every couple of years to keep from falling too close to the earth or sun

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