Aerodynamic Analysis of Deorbit Drag Sail for CubeSat Using DSMC Method

Round 1

Reviewer 1 Report

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Comments for author File: Comments.pdf

The English is good. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

aerospace-2944250-peer-review-v1

Dear editor and authors,

Manuscript: THE AERODYNAMIC ANALYSIS OF DEORBIT DRAG SAIL

FOR CUBESAT USING DSMC METHOD

 The authors present a study focusing on the aerodynamic characteristics of a CubeSat before and after the deployment of a drag sail. To analyze aerodynamic properties, models are taken into account; direct Monte Carlo simulation method and the theory of Free Molecular Flow. Where a comparison between the two models is presented. The drag sail is used for space debris mitigation.

The manuscript is well written and presents good results. I recommend publishing the manuscript.

I suggest only minor suggestions and/or corrections.

1)     Pg. 5, Line 137 and 138: In “Thus, a total of 9 attitudes are produced and labeled” please replace by “, This table does not show the altitude but the angle values. I think you should review this.

2)     Pg. 8, line 146. In “To confirm the flow regime, Knudsen numbers of the flow for” Please indicate a reference for the Knudsen numbers.

3)     Pg. 8 line 174 and 175: In “of 10, 12, and 3 mN respectively”. “is evident that the deorbiting capability of the 4 m2 sail is comparably effective to that of electric thrusters”.  In this case, the 4 m2 sail is not just comparable to microwave ion?

4)      Pg. 8 line 178: In “drag sail for all 9 attitudes” As previously mentioned, as Table 3 does not include altitude, it is difficult to relate. In table three, 9 cases appear with different angles, but not altitude.

5)     Pg. 8 line 181: In “According to Fig. 10, FMF shows good consistency, for vertical incidence cases, with DSMC results for altitudes larger or equal to 185 km.” But, this is only true for the case of Fig. 10 a).

6)      Pg. 8: The angle of attack alpha and the angle of sideslip beta are not commented on in section 4.3, as they are different for the cases analyzed according to Table 3, so I believe that a comment should be made regarding these angles.

7)     Suggestion: include a short paragraph between sections and/or subsections, such as 5 and 5.1

8)     Pg. 11, line 255 e 256: In “When compared to scenarios with a constant CD, the deorbiting time in cases where CD varies is notably shorter.” Fig. 11 shows a very small difference when comparing the coefficients. I don't understand "CD varies is notably shorter" Note that what really contributes to deorbitation is the drag sail that is discussed on pg. 12 line 275.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

no comments.