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Robertson, D. R.

Publications and source records attributed to Robertson, D. R..

3 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Use of polarization methods in earth resources investigations

The use of polarized light image pairs to investigate earth resources and to make meteorological and oceanographic observations is discussed. The differences between the pairs are found to contain a significant amount of information on contrast, contrast boundaries, shadow, and such terrestrial features as rivers. Combinations of the polarization images were used as input to a principal component analysis, which provided some useful pictorial information not contained in any of the input images. Differencing the Fourier spectra of the polarization image pair showed that significant differences exist between the images in the population, azimuthal distribution, and spatial frequency distribution of contrast boundaries.

Duggin, M. J.↗
NASA NTRS1975

Manufacture and static firing of X259-E6 rocket motor serial number XJ04/0001

A single motor was cast and static fired to demonstrate the performance of high energy crosslinked double base (XLDB) propellant in standard X259 rocket motor hardware. Prior to motor fabrication, the motor was analyzed to predict the results of static firing the X259 motor loaded with XLDB propellant. As a result of the analyses, a forward dome shrinkage liner was added to the design. With this design change it was determined that adequate margins of safety existed. The motor, designated the X259-E6 model with serial number XJ04/0001, was fabricated using a slurry-casting technique and was assembled with a standard X259-B4 nozzle which had the nozzle throat machined to a smaller inside diameter than the B4 model and the exit cone cut short for Bacchus Works altitude expansion. The motor was static fired on 20 February 1974 with the nozzle failing during motor operation. Nozzle failure was attributed to spalling of the throat material leading to complete nozzle break-up. However, the propellant functioned as predicted in the motor chamber, ignition was normal, and char and erosion of the internal insulator were as expected.

Robertson, D. R.↗