In regards to the James Webb telescope(congrats, NASA!): How does the solar shield NOT act like a solar wind sail, which would cause the telescope to be steadily pushed away from us and require frequent re-alignment?

Question

In regards to the James Webb telescope(congrats, NASA!): How does the solar shield NOT act like a solar wind sail, which would cause the telescope to be steadily pushed away from us and require frequent re-alignment?

In: 143

Answer 1

First, solar light has many many many times more effect than solar wind. Then, the shield acts as a light sail, but it’s rather small force (at this distance from the Sun the force is about 1/100th pound per acre or about 1kg per square kilometer) but it’s accounted for in orbital positioning (the orbit would be slightly shifted towards the Sun to counter that).

The main effect is that solar radiation would try to rotate the craft to “topple” it, as the mass behind the shield isn’t symmetrically distributed. But this is accounted for too, as the craft has special solar radiation “rudder” which allows countering this.