Grid Deformation Real-Time Measurement System of Ion Thruster Based on Videometrics

Round  1

Reviewer 1 Report

Dear Authors,

I'm happy to see you could proceed in the direct measurement of ion optics grid dispalcement/deformation under operational conditions. I have only minor remarks:

124 ff Hardware discription (126...)

Could you include more demnsions of the setup? At least the distance camera to the pins/objects should be given

Fig 12 (a), the discription of the plots is confusing.

Thank you for your work!

Author Response

Thank you very much for your review. Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors presented a very nice work concerning ion thruster grid deformation. It is indeed a very relevant subject which hasn't been fully understood until now. With the authors' work, a necessary step in the right direction has been taken. In my opinion, the work is very important for the respective community and the paper should be published (after a thorough revision). There are some things that have to be addressed before publication of the manuscript.

1) Please have the manuscript checked by an English native-speaker. There are too many errors, missing letters and linguistic obscurities in the manuscript to have it published just yet.

2) In the manuscript only a parabolic temperature distribution at the grids is assumed. However, some studies (e.g. R. Henrich, PhD thesis, University of Giessen, 2013 [http://geb.uni-giessen.de/geb/volltexte/2014/10799/pdf/HenrichRobert_2013_12_17.pdf]) show that the parabolic distribution vanishes and a higher order one sets in in the case of high mass utilization efficiency. This has also been observed in terms of higher order mechanical modes of the extraction grids. Could you comment on that? Would your method still be applicable (by placing another set of cooperative targets to an additional location on the grid)?

3) Fig. 3 shows Chinese symbols. I strongly suggest translating them to English to improve the optical quality and the international impact of the paper.

Author Response

Thank you very much for your review. Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

In this paper, a non-contact videometrics system using a telemicroscope is designed and the displacements for three cooperative targets are measured to conduct the high-precision measurement of the LIPS-300 ion thruster grid deformation in the vacuum. The measurement method itself was proposed by Soulas; however, the authors successfully installed a scheme of the cooperative targets that can measure the deformation of the three grids ion optics and improve the measurement accuracy by using subpixel positioning. The technology proposed by the authors are useful for ion thruster developers. This paper is worth publication in the journal with minimum corrections. The followings are comments on the article.

 Line 18: “.. the power of 750W…” -> “.. the power of 750 W…”

Place a space between the number and an abbreviated unit of measurement.

Line 92: … grid gap variation are samll, -> grid gap variation are small

                   Including this one, there are several typos in the article.

Line 105: “..the probes with snap structure and thread structure..”

What are the snap and thread structures?

Line 220 and 225: I don’t understand the terms of “class-B uncertainty” and “class-A uncertainty”? What do they mean?

Line 245: The definitions of the axis in Figure 7 and the axis in Figs. 8 and 9 seem to differ with each other.

Line 334: It is very difficult to distinguish the screen, accelerator and decelerator grid deformations. Their symbols are too small to reads They are all black lines!

Author Response

Thank you very much for your review. Please see the attachment.

Author Response File: Author Response.pdf