Attitude control strategy of a transformable spacecraft for orbital station-keeping around sun-earth L2

This paper proposes the control method which achieves fuel-free station-keeping around Sun-Earth L2 point (SEL2). This station-keeping is driven with only solar radiation pressure (SRP), and therefore the orbit is maintained without fuel consumption by controlling attitude of a spacecraft toward the sun. Furthermore, this attitude control is also achieved without fuel by using the technique of non-holonomic turn. The target orbit is the artificial orbit around SEL2, the size of which is much smaller than typical halo orbits, and thus provides more stationary thermal condition to spacecrafts.