Survey of CO2 Radiation Experimental Data in Relation with Planetary Entry
Round 1
Reviewer 1 Report
This work provides an extensive review of experimental activities on pure CO2 and CO2-N2 high-speed flows with relevance to Venus and Mars atmospheric entries. The review is focused on shock-tube data, which is a key facility for such studies, but also presents data issued from other high-enthalpy plasma facilities which are relevant for these studies, such as supersonic arcjets or ICP torches. The work is well structured, thorough and compreensive, with just a few minor rearrangements needed for improving the clarity of the manuscript. My main comments are: - Data from the VUT-1 facility is presented in two different sections of the manuscript. Once for pure CO2 flows and once for CO2-N2 flows. The author should consider merging these two sections in a single one as it would improve the organization of the article. - No mention is made of the CO2 UV absorption measurements (Chemiluminescence) carried out in VUT-1. These are very useful for validating CO2 kinetic and dissociation models, as seen in a recent preprint (https://arxiv.org/abs/2006.10426). This data should be included in the review. - A lot of figures are bitmaps with very low resolution. If higher resolution figures cannot be sourced, the authour should consider extracting the data and reploting the data with an adequate software (for example engauge, which is available for different software platforms and free software). After these suggestions are taken into consideration, the paper may be accepted.
Author Response
As requested a section has been devoted to VUT-1 results, the same has been done for those from IRS PWK3 facility.
The survey emphasis on VUV and IR data, and UV data from chemiluminescence have not been included. It can be done but for that a clear reference (author+title+journal or conference) in which this data are published shall be provided. In the indicated paper (Arxiv website), data from chemiluminescence are mentioned in different parts of the contribution, but without indication of the facility in which they have been obtained.
Concerning the figures, an effort has been done in increasing their quality but the software mentioned "engauge" is used to extract data and manipulate them: due to the time required and the number of figures the corresponding effort is beyond the scope of the survey. additionally, it seems there was a lost of quality in the figures during the processing of the paper after its upload.
Reviewer 2 Report
See attached file
Comments for author File: 
Comments.pdf
Author Response
Comment of the reviewer: A breif discussion as well as a relating phraseology on the Löhle reference would be adequate here.
Answer: The paper mentionned above has been recovered, but since it has a very low scanned quality it is difficult to exploit.
A section has been devoted to IRS results. Most of the other comments have been accounted for when possible. Exception has been done with the comments related to experimental techniques not directly related to available radiation datasets: this point is outside the scope of the paper.
Reviewer 3 Report
Dear Author,
The majority of my comments are in the attached PDF. In general, I consider this paper as very important but I think there is still some work to do, see the attached PDF.
Regards
Comments for author File: Comments.pdf
Author Response
Firstly, the author wants to thank the reviewer for the effort done and for some the soundness of the remarks.
Most of the comments have been accounted for, however the author has some comments on the following points:
1/ Concerning the figures, an effort has been done to improve the quality of some, moreover it seems that the quality of the figures has been degraded during the uploading of the documents. If necessary some figures will be suppressed.
8/ The scope of the study was to focus on experimental datasets, some numerical reconstructions have been mentionned when they were parts of the papers in which the data were published. As a consequence modeling studies are not in the scope of the review, they would require a dedicated paper … If the reviewer insists references of JAXA work can be added, but they shall be provided.
19/ The author knows the C. Laux works on air and VUV radiation. I do not find the same for CO2. I think the reviewer shall be more accurate and give a proper reference of the work on CO2 radiation, particularly if measurements were performed in infrared or VUV. The documents I have are more focused on experimental techniques than on CO2 radiation datasets obtained in Centrale plasma torch.
20/ Could you provided the reference of the Caltech's work ?
Round 2
Reviewer 3 Report
Dear Author,
I am happy with the paper.
There is some minor things to mention:
- The Figure mentions in the text do not seem to be linked to the relevant figure numbers anymore. Can you fix this?
- You inserted some references on IRS activities using Romanian numbers instead of Latin numbers. Can you fix this?
Given that these two aspects were fixed I would agree to engage publication.
Regards
