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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS1963

RADIATIVE ENERGY TRANSFER ON ENTRY INTO MARS AND VENUSQUARTERLY REPORT NO. 4

The emissivity of carbon dioxide in the 2.7 4 µ region has been measured at temperatures from 2000°K to 3500°K, for optical densities less than 5 atm-cm. The high temperatures were obtained by passing a shock wave through the test gas. A total gas pressure of one atm was maintained by varying the carbon dioxide concentration in an inert gas. Emissivities obtained from absorption and emission measurements are in agreement. results are compared to an approximate method for calculating emissivity, The which considers the molecular population concentrated in a single band whose center is temperature dependent. A comparison with previous results suggests that this single band model will overestimate the peak and underestimate the width of the observed values. The observed and calculated emissivities are in agreement if the intensities of the (n 1 +1,n 2 , n 3 + 1 → n 1 , n 2 , n 3 ) and (n 1 ,n 2 +2, n 3 + 1 → n 1 , n 2 , n 3 ) transitions are assumed proportional to (n 1 +1) (n 3 +1) and (n 2 +1)(n 3 +1)/2. The use of this single band model which was originally intended to provide a rough prediction of emissivity, indicates that the use of the appropriate terms of the electric dipole expansion is satisfactory for the (n 1 +1,n 2 , n 3 + 1 → n 1 , n 2 , n 3 ) transition, but is not for (n 1 ,n 2 +2, n 3 + 1 → n 1 , n 2 , n 3 ) transition.

radiative heat transfer↗
NASA NTRS1963

THE DETECTION OF WATER VAPOR ON MARS

We have found eleven weak lines of water vapor on a high dispersion near-infrared spectrogram of Mars taken at the coudè focus of the Mount Wilson 100-inch reflector on April 12/13,1963. We exposed 43 hours on ammoniated IV-N emulsion with a dispersion of 5.6 A/mm; the plate is well exposed at the poles and somewhat overexposed at the center of the planet’s disk. The Martian H 2 O lines in the X 8200 water-vapor band are displaced 0.42 A longward of their telluric counterparts due to the relative velocities of the earth and Mars: AV = +15 km/sec on that date. The Martian lines are strongest over the poles of the planet-we set the spectrograph slit daost north-south to cover both polar regions. This apparent polar strengthening of the Martian H 2 O lines is at least partially due to the increased air mass through the line of sight to high latitudes.

WATER VAPOR↗