Path Planning for Self-Collision Avoidance of Space Modular Self-Reconfigurable Satellites

Round 1

Reviewer 1 Report

The authors have improved the paper and it is accepted in the present form.

Reviewer 2 Report

I have reviewed the amended article and read the additional text that has been added. This explains the derivation of the original cube sat designs and the subsequent logic of the Modular SCASMSC Statellites. The revised text provides a fuller explanation of the advantages that this type of flexible spacecraft architecture can provide. I find the article to be significantly improved and recommend its publication.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The basic premise of the article as to the efficiency and effectives of a module design with many different missions and application, and especially as to defense related applications is not explained. Therefore the value and purpose of the overall article is hard to understand. Until this issue is clearly addressed it is hard to evaluate the merits of the article. Are defense related applications and commercial applications to be combined? And so on?

Reviewer 2 Report

Interesting paper on a modular satellite design. My recommendations follow:

1. The "more technical" part of the paper is very extensively developed and contains lots of details. This cannot be said about the application you want to design. The SMSRS satellite concept needs to be better conceptualized in a dedicated section with size, mass of each unit and an overview of the possible mission concepts (reconfigurable camera or SAR systems are interesting), stowed and deployed configuration sizes, scalability (see next point). Even if the results can be preliminary due to the technical content of the other sections, preliminary results (or at least preliminary) shall be presented
2. Can the mission concept conceived as scalable and involving CubeSat or CubeSat-like units? Can the similar payloads (to be better presented in section 1) be fit in 10-cm like units?
3. What kind of mission scenario do you foresee for this satellite? And why only defense/military? Why civilian uses are not considered for the scope? Which orbit can be applied to the satellite?
4. I would avoid bullet points and numbered lists in the conclusions. Give the conclusions as single paragraph.
5. In the description of the system, some explanations might be needed for operative modes: which configuration would you use for a phase of the mission, for battery recharging etc. In which configuration could you launch the satellite
6. Some of the remarks on sensors need to be carefully reviewed: attitude sensors (even high precision absolute attitude sensors) can be costly, but how can this cost relate to the joints total manufacturing cost, considering that every joint is an important point of failure for the mission?
7. When introducing the CubeSat missions, a remark on the (usually) higher risk that they imply could be added. On this purpose, you should extend the bibliography with risk scenario evaluation for small satellites, such as:
   1. Menchinelli et al., A reliability engineering approach for managing risks in CubeSats, Aerosspace, 5,4,121 (2018), doi:10.3390/aerospace5040121
   2. Durmaz, Ozgor Demirkaya, Reliability considerations for design of space systems, 5th Intern. Conf. on Recent Advances in Space Technologies (RAST), 2011, article code 86246
   3. Yang et al., Failure analysis of deployment mechanism of a satellite solar array, ICRMS'2011, pp. 931-937, 2011, doi:10.1109/ICRMS.2011.5979419
8. Speaking of bibliography improvement, I believe the reference list lacks of a true "space mission" part while we can consider it complete on the technical robotics part. I suggest to increase the number of references to better introduce the space mission. Some suggestions with small satellite missions concepts that can be cited as "baseline" for the modules of the satellite mission:
   1. Cialone et al., A concept mission for the Stellar Population and Evolution with Cubesats (SPEC), Advances in Space Research, 63(1), pp.800-811, doi:/10.1016/j.asr.2018.10.012
   2. Santoni et al.m GreenCube: Microgreens cultivation and growth monitoring on-board a 3U cubesat, 7th International Workshop on Metrology for Aerospace, June 2020, doi:10.1109/MetroAeroSpace48742.2020.9160063
   3. Cervone et al.,:Phase a design of the LUMIO spacecraft: A cubesat for observing and characterizing micro-meteoroid impacts on the lunar far side, Proceedings of the 71st International Astronautical Congress;
9. Have you considered the potential impact of such mission for tracking and space traffic management if released in LEO? A short remark should be worth mentioning.

Reviewer 3 Report

The paper proposes a new method for joint path planning for SMSRS self-collision avoidance. The paper sounds good and interesting; however, some points should be improved such as:

• The Introduction is very long where it spans about four pages! It is suggested that splitting the Introduction section and add descriptive or related work sections.
• In the Introduction section, the paragraph from line 35 to 40 should be rephrased as it contains a repetitive “and”.
• The organization of the Introduction section should be revised. In line 41, the authors introduce the paper contribution which is advised to be at the end of the Introduction and preferably in a subsection called “Paper Contribution”.
• The related work should be orderly displayed. Line 71 switched back to related work after introducing the proposed satellite module.
• Line 76 states that there are two common methods to establish the collision detection. Please add the corresponding references.
• In line 147, there is an extra “S” in the acronym “SSMSRS”.
• In line 172, please add the reference corresponding to FK.
• Equation (1) requires the corresponding references otherwise it is proposed by the authors. It should be decided.
• Figure (5) in page 7 should be organized in clearer flowchart showing the start, operations, conditions, decisions, etc.
• Some references are very outdated and point to more than 20 years back. It is recommended to replace them with some recent ones in the same field of the paper.