NASASpaceFlight.com Forum
General Discussion => Q&A Section => Topic started by: cube on 04/17/2022 02:40 pm
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Hello I was wondering about this, during certain trajectory correction maneuvers around L2 the james webb space telescope must be placed in a certain position for the maneuver, this is not problematic for the temperature of certain instruments which could be exposed to the sun and warm up?
Thank you !
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Hello I was wondering about this, during certain trajectory correction maneuvers around L2 the james webb space telescope must be placed in a certain position for the maneuver, this is not problematic for the temperature of certain instruments which could be exposed to the sun and warm up?
Thank you !
The maneuvers only require thrust towards the sun.
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Hello I was wondering about this, during certain trajectory correction maneuvers around L2 the james webb space telescope must be placed in a certain position for the maneuver, this is not problematic for the temperature of certain instruments which could be exposed to the sun and warm up?
Nothing on the cold side of JWST is supposed to be exposed to the Sun ever again. The spacecraft and the orbit trajectory were designed so they can perform station-keeping maneuvers with the mirrors and instruments still in the shade.
The station-keeping thruster is on the hot side of the sunshade, so it can't push JWST towards the sun directly. The thruster can push JWST diagonally away from the Sun. With JWST tilted backwards as far as it can go (53º before the sun hits any cold parts), the thruster points sideways, perpendicular to the line to the Sun.
But orbital mechanics means JWST can manipulate its orbit without thrusting sunwards. Consider a satellite in orbit around Earth. It could raise or lower or tilt its orbit with few restrictions even if it could never thrust in a sunward direction. JWST is in orbit around the L2 point where there is no planet, but it can still control that orbit well enough using its limited range of thrust directions.
(There was one part of the mission where JWST's thruster constraints were a big problem: the approach and orbit insertion at L2. JWST can't thrust sunward, so if it was moving too fast away from the Sun on its way to L2 then it had no way to slow down. The Ariane 5 launch was deliberately a little bit slow to make sure JWST didn't overshoot its target.)