The Development of a Next-Generation Latticed Resistojet Thruster for CubeSats
Round 1
Reviewer 1 Report
Comments and Suggestions for Authorsline 247: make unit "degrees" unambiguous
line 259: element Cr is chromium, not chrome
Table 3: the four data points do not merit a table of their own, they might very well be merged into Figure 5 (this would also make the data easier to associate with the concepts)
lines 547 ff: formula (5) is the specific impulse, should not be called propulsive efficiency (there are verious measures of efficiency), and the formula is certainly not the definition of specific impulse, but a derivation
line 553 does not start a new paragraph
line 562: root sign is broken, and this is not the definition of \dot{m}, and the definition of A_t seems to be missing.
Apart from these petitesses, one concern is that in order to be able to judge the signifinace of the experimental results, one would need to know what kind of uncertainty analysis was done. GUM? Purely statistical (type A) or taking into account type B uncertainties.
The systematic deviation of the heater cartridge internal thermocouple from the wall temperature (the latter expected to be lower) should not be treated en passant with a short remark at the end of the paper. Since this appears to be an essential quantity in the calculations, one would expect some discussion how to take this into account in the calculations as early as possible.
In general, the paper is very well written and hence enjoyable to read. The introductory part and literature review are certainly enough in-depth, at some point the reviewer even had the impression that the article was developing into more like a review paper.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsReview of manuscript
The Development of a Next Generation Latticed Resistojet Thruster for CubeSats
By Daniel Turner, Robert Howie, and Phil Bland
This paper deals with a newer approach concerning resistojet manufacturing for cubesats. The paper is easy to read and the English is fine. Only very few errors may be corrected. It should be published after minor modifications.
Detailed Comments
Heater temperature: Is it correct that for the model the heater was around 373 K? Why that, as such a low temperature does not help a lot with respect to increasing ISP? A model could go much higher, and issues may only appear when it comes to building hardware. And issues with nitrous oxide decomposition may also appear only at higher temperatures.
Line 170: resistojet duplicate
e.g. line 397: … “The manufacturability and thermal performance analysis of GRCop-42 lattice structures is unexplored literature. Thus, the investigations conducted… “ -> Please add a few more details about the material GRCop-42, and its additive printing options.
Line 443: … test bench and load cell: Please add more information about the load cell assembly. I doubt that the measurements are so easy and the errors are small. I would expect errors due to the heavy feed pipework, and strain caused by changing propellant pressure. Also, the short runtime will cause transient thermal effects on the thruster-load cell assembly. In any case, error analysis and error bars are needed for thrust measurement.
Line 471: guess it is National Instruments.
Line 501: … reason, 1 minute, 2 minutes and 3 minutes heater warm up periods ….
Eq 5 and 6 need a better format
Line 576: …. “Interestingly, the resistojet thrust slightly decreases rather than remaining constant… “ -> See my comment on the load cell.
Improve format of Eq (7)
Line 639: please rework the sentence: The latticed resistojet thruster therefore demonstrates a significant reduction in system mass and …..
Comments on the Quality of English LanguageThe paper is easy to read and the English is fine!
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsAll my comments are in the attached file.
Comments for author File: Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
