In-Situ Optical Measurements of Solid and Hybrid-Propellant Combustion Plumes

Round 1

Reviewer 1 Report

This paper proposes a combustion flame observation technique of a hybrid rocket using fiber‐optic cables and proposes a useful technique for the combustion characteristics of the hybrid rocket. The content is also no problem, and only the minor correction is sufficient.

The pressure in Figure 11.1 should be expressed in SI units.

Author Response

please see attached document.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is about proof-of-concept for flame temperature measuring and possible measurements of species concentrations. The paper is quite interesting and physically good but I have some comments.

1. When the optical fiber is held at a high temperature in the atmosphere, its mechanical strength decrease hardly. The authors made a test for optical fiber in flame but there is no words about possible lifetime. The authors should add such an information
2.  The authors said that the fiber tip can be melted in flame. The melted fiber tip transmittes the light but will strongly affect the spectral response of all the system. The authors used only the spectrometer calibrations function, but don't take in account this point. It should be discussed.
3. On figure 9 the ticks label are too small and the chemical formulas should be written with subscripts (H₂O not H2O)

I think the paper can be published in the Aerospace after the minor revision.

Author Response

PLease see attached document.

Author Response File: Author Response.pdf