scenarioDragRendezvous

Overview

This script sets up a formation flying scenario with two spacecraft. The deputy spacecraft attempts to rendezvous with the chief using attitude-driven differential drag using the strategy outlined in this paper.

This script is found in the folder src/examples and executed by using:

python3 scenarioDragRendezvous

The simulation layout is shown in the following illustration. Two spacecraft are orbiting the earth at close distance. Perturbations from atmospheric drag, provided by exponentialAtmosphere and facetDragDynamicEffector, are implemented by default; the \(J_2\) gravity perturbation can also be included. Each spacecraft sends a simpleNav output message of type NavAttMsgPayload continuously to a hillStateConverter module, which is assumed to be a part of the deputy (maneuvering) spacecraft’s flight software stack. The hillStateConverter module then writes a HillRelStateMsgPayload, which is read by the hillToAttRef module implementing the differential drag attitude guidance law.

Illustration of Simulation Results

0.0, #   altitude offset (m)
0.1, #  True anomaly offset (deg)
1, #    Density multiplier (non-dimensional)
ctrlType='lqr',
useJ2=False

In this case, the deputy spacecraft attempts to catch up to a reference set ten kilometers ahead of it along-track using a static LQR control law, without considering the impact of \(J_2\) perturbations. The resulting relative attitude and in-plane Hill trajectory are shown below.

Time trajectories of the in-plane Hill components of the Deputy are shown here: