  Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) was launched on
May 22, 2018. It carries the Laser Ranging Interferometer (LRI) as a technology
demonstrator that measures the inter-satellite range with nanometer precision
using a laser-link between satellites. To maintain the laser-link between
satellites, the LRI uses the beam steering method: a Fast Steering Mirror (FSM)
is actuated to correct for misalignment between the incoming and outgoing laser
beams. From the FSM commands, we can compute the inter-satellite pitch and yaw
angles. These angles provide information about the spacecraft's relative
orientation with respect to line-of-sight (LOS). We analyze LRI derived
inter-satellite pointing angles for 2019 and 2020. Further, we present its
comparison with the pointing angles derived from GRACE-FO SCA1B data, which
represents the spacecraft attitude computed from star cameras and Inertial
Measurement Unit (IMU) data using a Kalman filter. We discuss the correlations
seen between the laser based attitude data and the spacecraft temperature
variations. This analysis serves as the basis to explore the potential of this
new attitude product obtained from the Differential Wavefront Sensing (DWS)
control of a FSM.
