I don't think you'd even need to retract the sail - just structure it differently. There's an omni-directional wind turbine (https://newatlas.com/2018-dyson-aw

I don't think you'd even need to retract the sail - just structure it differently. There's an omni-directional wind turbine (https://newatlas.com/2018-dyson-award-winner-o-wind-turbine/57221/ https://newatlas.com/2018-dyson-award-winner-o-wind-turbine/...) which sort of encapsulates what I'm thinking of. I'm not too sure about how easy it would be to use a non-planar sail to redirect photons in the direction required to constantly build forward momentum - but a photonic "wind" turbine used to power a quantum dot emitter array might be able to do something.