RD1 generates power 99% of the year and collects solar radiation by autonomously redirecting its reflectors toward a concentrator to focus sunlight throughout each day. RD2 uses flat panels, with solar cells facing away from Earth and microwave emitters facing toward the Earth. RD2 generates power 60% of the year due to its limited capability to reposition itself or redirect solar radiation toward its solar cells.
https://ntrs.nasa.gov/api/citations/20230017756/downloads/ASCEND SBSP Final 05162024.pdf