Quote:
Originally Posted by E23
It has to be near the meridian around midnight as well as near the ecliptic continuously when it gets to L2.
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Webb will orbit around L2, in a "halo orbit" similar in size to the Moon's orbit around the Earth, taking about 6 months to complete.
https://webb.nasa.gov/content/about/orbit.html
Since L2 is about 4 times as far from Earth as the Moon, JWST's apparent motion from Earth should be something like an ellipse around a point directedly overhead at midnight, but about 10 to 15 degrees away.
By orbiting around L2, but never actually getting close to the Sun-Earth straight line, it will always be in full sunlight, and will always be generating full solar power. (This also minimises the thermal distortion effects that would arise if it was to pass in and out of the Earth's shadow.) It also means that the comms link to Earth is always pointing well away from the Sun - which would be problematic for interference etc.
It's all very clever - when people say of something mundane that "it ain't rocket science" - THIS is the sort of complexity and ingenuity they're talking about!