Blast Effects of Rocket Nozzles on Visibility During Landing ~ 1963 NASA Langley Research Center (Patreon)

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'1964 NASA Langley Research Center visibility studies of landing on a dusty or particle covered surface. The study examined the effect of twin variable-cant rocket nozzles (to simulate landing) on surfaces covered with particles of various sizes and depths.' NASA Langley film  L-689.

Originally a public domain film from NASA, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.

The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19650002904.pdf

BLAST EFFECTS OF TWIN

ON VISIBILITY DURING LANDING

VARIABLE-CANT ROCKET NOZZLES

ON A PARTICLE-COVERED SURFACE

Langley Research Center

Langley Station, Hdmpton, Va.

TN D-2455

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. DECEMBER 1964

SUMMARY

A limited investigation has been conducted to determine the jet-blast effect of twin variable-cant supersonic nozzles. These tests were made to examine the result of using canted main rocket engines to sweep the blast debris outward from the proposed landing area of a rocket-powered vehicle maklng a vertical approach to a touchdown. Cant angles from 0 degrees to 75 degrees', at intervals of 15 degrees, were tested at low ambient pressure and at atmospheric ambient pressure. Nozzle chamber pressures used were 400 psi and 2000 psi.

Observation of the blast effects in low ambient pressure and in atmospheric pressure environments indicate that much better visibility might be expected in landing on the moon's surface than a landing under similar circumstances in the earth's atmosphere. Experience with VTOL jet aircraft landing in loose material would then give a pessimistic view of what is to be expected if a jet of equal thrust were used to land on the moon's surface. Simulation of lunar landings with rocket vehicles on earth may possibly give a realistic visibi.lity simulation if nozzle cant angles of about 45 degrees are used on earth to simulate the lunar landing, because the visibility away from the plane of the cant will be about equal to visibility under low atmospheric-pressure conditions. However, visibility into the direction of the cant would be poor and if the vehicle is traveling in that direction, obstacles may not be seen until possibly too late for corrective action to be taken by the pilot...