SBIR-STTR Award

The impact of atmospheric particles on a nosetip material during reentry results in the generation of debris particles which are ejected from the crater formed. These debris particles have the potential for significantly eroding any downstream protruding surfaces such as a flare. Consequently, the characteristics of this ejected debris such as its velocity, trajectory, and size distribution are needed for reentry vehicle or missile design. Attempts to-date to obtain this data have not been successful because of the inadequacy of the available instrumentation. A measurement technique not utilized heretofore for this data and which is recommended because of its ability to freeze high speed motions and its good depth of field characteristics is pulsed laser holography. In Phase I of the proposed study, an existing holocamera will be modified and made available for debris characterization impact tests. The proposed effort will include reconstruction of holograms and obtaining debris characterization data from them. Phase I will provide verification of the measurement technique for this application and data which will enable upgrading the measurement capabilities in future efforts.

The objective of this program is the development of a highly reliable field usable holocamera which will provide high resolution holograms of dynamic particle fields and test specimens during testing in a hypervelocity test facility. Specific objectives for this holocamera include the ability to provide: a resolution of 5-10 microns, or smaller, particles in a 2-4 inch diameter field of view; a double pulse capability with 1-50 microsecond pulse separation; a laser pulse width of 20 nanoseconds or less; fully automated sequencing of the timing with the capability for microsecond synchronization for the lasing and millisecond synchronization for the flashlamp; the ability to operate in a vacuum, dirty, limited access, and high electrical noise environment; remote diagnostic and control; and high reliability and low maintenance.