Hardware-in-the-loop Proximity Operations in Cislunar Space

Space missions to Near Rectilinear Halo Orbits (NRHOs) in the Earth-Moon system are upcoming. A rendezvous technique in the cislunar space is proposed in this investigation, one that leverages coupled orbit and attitude dynamics in the Circular Restricted Three-body Problem (CR3BP). An autonomous Guidance, Navigation and Control (GNC) technique is demonstrated in which a chaser spacecraft approaches a target spacecraft in the southern 9:2 synodic-resonant L2 Near Rectilinear Halo Orbit (NRHO), one that currently serves as the baseline for NASA's Gateway. A two-layer control approach is contemplated. First, a nonlinear optimal controller identifies an appropriate baseline rendezvous path, both in position and orientation. As the spacecraft progresses along the pre-computed baseline path, optical sensors measure the relative pose of the chaser relative to the target. A Kalman filter processes these observations and offers precise state estimates. A linear controller compensates for any deviations identified from the predetermined rendezvous path. The efficacy of the GNC technique is tested by considering a complex scenario in which the rendezvous operation is conducted with a non-cooperative tumbling target. Hardware-in-the-loop laboratory experiments are conducted as proof-of-concept to validate the guidance algorithm, with observations supplemented by optical navigation techniques.