Lightweight Design for Active Small SAR S-STEP Satellite Using Multilayered High-Damping Carbon Fiber-Reinforced Plastic Patch

Round 1

Reviewer 1 Report

Dear Authors,

Reviewer's comments can be found in the file attached.

Regards

Comments for author File: Comments.pdf

 Extensive editing of the English language required

Author Response

Dear reviewer.

We appreciate your kindly comments.

Thanks to your opinion, our manuscript could be revised.

Point-by-point responses for the comment are shown in the attached file.

The manuscript file is prepared as two versions;

1. marked version with PDF form
2. clear version with DOCX form

The manuscript files will be sent by Editor's Email.

Best regards

Hyun-Guk Kim

 

Author Response File: Author Response.docx

Reviewer 2 Report

1.The mechanism of reducing vibration response by using Multilayered High-damping CFRP-based Patch needs to be described. Conclusions must be comprehensive and not written like a test report.

2.The damping performance parameters of the Multilayered High-damping CFRP-based Patch should be given.

3.The author should supplement the data related to vibration performance, such as the mass, stiffness, damping, etc. of the structure before and after using the Multilayered High-damping CFRP-based Patch.

4.Some sentences in the abstract are missing punctuation mark.

Author Response

Dear reviewer.

We appreciate your kindly comments.

Thanks to your opinion, our manuscript could be revised.

Point-by-point responses for the comment are shown in the attached file.

The manuscript file is prepared as two versions;

1. marked version with PDF form
2. clear version with DOCX form

The manuscript files will be sent by Editor's Email.

Best regards

Hyun-Guk Kim

Author Response File: Author Response.docx

Reviewer 3 Report

In this paper, an additional vibration damping structure is developed for active S-STEP small SAR satellites to reduce dynamic loads without major design changes, in response to the problem of intense vibration during launch. The damping structure is a CFRP-based laminated patch that not only has a damping effect, but also meets the needs of lightweight design. The structure utilises the damping properties of CFRP itself to achieve a passive vibration isolation effect, which has some practical application value, but there are some issues in the paper that require further explanation from the authors.

(1) Section 3.2 of the paper mentions that "the selection of test specimens takes into account the frequency range of the most significant increase in satellite vibration", but it does not mention the law of influence between them, and there is a lack of references to support this.

(2) Satellites emit heat in the course of their operation, will pasting CFRP patches on the surface of the satellite affect the heat dissipation of the satellite, thus reducing the performance of the satellite?

(3) The working conditions of satellites in the space environment are more complicated, and the temperature range is from -250℃ to 80℃, with a large temperature difference, will the CFRP patch affect its performance if it works for a long time in such an environment?

(4) It is mentioned in the article that as the number of layers of CFRP patches increases, the vibration damping performance increases, but the quality also increases, how to consider the trade-off between vibration damping performance and structural quality? Can we add the parameter optimisation design in the article to explain this part.

(5) The article simply converts the vibration of the satellite launching process into sinusoidal vibration and random vibration, which is unable to fully simulate the complex launching environment of the satellite, and the experimental results are hardly convincing.

Moderate editing of English language required.

Author Response

Dear reviewer.

We appreciate your kindly comments.

Thanks to your opinion, our manuscript could be revised.

Point-by-point responses for the comment are shown in the attached file.

The manuscript file is prepared as two versions;

1. marked version with PDF form
2. clear version with DOCX form

The manuscript files will be sent by Editor's Email.

Best regards

Hyun-Guk Kim

Author Response File: Author Response.docx

Reviewer 4 Report

1.       Mention the specific techniques employed to conduct the sine and random vibration tests at the specimen level.

2.       Kindly provide more details on the development process of the carbon fiber-reinforced plastic (CFRP)-based laminated patch.

3.       Is there any particular criteria or performance metrics used to evaluate the vibration reduction performance of the CFRP-based patch, if  so kindly include

4.       Were numerical or analytical models used to validate the experimental results of the CFRP-based laminated patch? If so, could you provide some information about these models?

5.       How was the structural stability of the S-STEP satellite assessed during the sine and random vibration tests? Were there any specific parameters or measures used to evaluate its performance?

6.       Were there any limitations or challenges encountered during the development and testing of the CFRP-based patch? If so, what were they and how were they addressed?

7.       List  the potential implications or applications of the findings from this study in the design and development of small SAR satellites or other space systems.

Comments for author File: Comments.pdf

Author Response

Dear reviewer.

We appreciate your kindly comments.

Thanks to your opinion, our manuscript could be revised.

Point-by-point responses for the comment are shown in the attached file.

The manuscript file is prepared as two versions;

1. marked version with PDF form
2. clear version with DOCX form

The manuscript files will be sent by Editor's Email.

Best regards

Hyun-Guk Kim

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

In order to solve the problem that the active S-STEP small SAR satellite vibrates violently during launch, an add-on structure which can reduce dynamic load without major design changes is developed in this paper. After the author's revision, the use of vocabulary and grammar has made great progress, but the colloquial expression needs to be further improved. In this paper, the factors considered in the experiment are relatively simple, in order to fully simulate the high temperature environment endured by the satellite during the launch process, and analyze whether the high temperature environment will affect the vibration damping performance of CFRP laminates. Secondly, there are some unclear problems in the pictures in the article. For example, the English comments in Figure 3 (a) cannot be read clearly.

After the author's revision, the use of vocabulary and grammar has made great progress, but the colloquial expression needs to be further improved.

Author Response

Point 1: After the author's revision, the use of vocabulary and grammar has made great progress, but the colloquial expression needs to be further improved. In this paper, the factors considered in the experiment are relatively simple, in order to fully simulate the high temperature environment endured by the satellite during the launch process, and analyze whether the high temperature environment will affect the vibration damping performance of CFRP laminates.

 

Response 1: We understand youur opininon. There are still several colloquial expressions in this manuscript. We revised the manuscript at the view point of colloquial expression. The research flow may appear simplistic. However, we want to emphasize that this study was conducted for only the structural characteristics, not the thermal. The CFRP-based patches is intalled at the satellite structure to withstand vibrational loads in launch environments, and even if crack of any structural problem occur in the orbital environment, there would be minimal impact on satellite operation. Furthermore, as mentioned in the previous review report, the structural integrity under thermal vacuum conditions was experimentally validated through STM environmental testing and thermal vacuum tests on adhesive joints, which is a matter currently being prepared for future publication.

 

Point 2: there are some unclear problems in the pictures in the article. For example, the English comments in Figure 3 (a) cannot be read clearly.

 

Response 2: We fully agree with your opinion. Too small font is possible to cause misunderstanding. These description with small fonts in Figure 3(a) is to nominate the specification of bolt at the interface and dimension of vibration excitor. The test configuration in Figure3(a) is made by using the drawng file came fron test facility. We show size of test specimen in Figure 2 of this manuscript and the specimen is linked with exciter using 4 bolting elements as shown in the Subsecection 3.2. Thus, we thought that the minor description for sepcmen and test facility is not needed. But, we are agree with your opinion. In order to reflect your opnion, we insert the detatiled description for sepcmen and test facility using large font.