Relative Dynamics and Modern Control Strategies for Rendezvous in Libration Point Orbits

Round 1

Reviewer 1 Report

This work provides a review of several control techniques and which are here implemented to achieve rdv along LPO. The manuscript is well written and the content is of interest, though the innovative aspects are limited. I suggest the authors to consider the following minor issues

1) The bibliography, though extended and full of details, is missing some relevant references to:

(1) early works on LPO station-keeping strategies, especially the pioneer work by Farquhar (i.e. R. Farquhar, “The Control and Use of Libration-Point Satellites,” NASA Technical Report, R-346, 1970 ;  R.W. Farquhar, H. Heuberger, “Trajectories and Orbital Maneuvers for the First Libration-Point Satellite,” Journal of Guidance and Control, 1980 Vol. 3, No. 6, pp. 549–554.).

(2) LPO station-keeping/rdv based on the analysis of the three-body (CR3BP, ER3BP, …) dynamics, which are also included in the analysis in Chapter 6 (i.e. Carletta S., Pontani M., Teofilatto P., Station-keeping about sun-mars three-dimensional quasi-periodic collinear libration point trajectories, Advances in the Astronautical Sciences, 2020, Vol 173, No. 227, 299-311 ; Canalias E., Masdemont J.J., Rendez-vous in lissajous orbits using the effective phase plane, Proceedings of the 57th International Astronautical Congress, 2-6 October 2006, Valencia, Spain)

2) The review on control techniques (i.e. pages 10-29) could be summarized reducing the total number of pages and giving more emphasis to the results. This would be helpful for the readers.

 

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Reviewer 2 Report

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Reviewer 3 Report

In this paper, the relative spacecraft dynamics in a circular restricted three body problem is addressed using a number of control techniques. The introduction is relevant and sufficient information about the previous studies results is presented for readers to follow the present study rationale and procedures. 

The methods are appropriate, although clarification on a few technical details is needed. Here are a few minor comments to consider for improvement of the paper:

1. Section 5.1, for the MPC approach presented, is the underlying problem assuming impulsive or low thrust control? If it is impulsive as I expect for MPC-MISG, I reckon the problem would require some form of mixed-integer formulation as the control can only take binary outputs- 0, Umax. That may explain the ~64 s computational time.

2. Section 5.1, how is the MPC prediction horizon determined?

3. For AL-LQR and other variants, the choice of Q and R matrices would greatly influence control costs. How are they chosen? 

Author Response

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