2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 132-2
Presentation Time: 9:00 AM-6:30 PM


HARRIS, Thomas H.S., Orbit Analyst, Lockheed-Martin, retired, Valley Forge, PA 19406, THSHarris@mindspring.com

Impact ejecta outflow perturbation may be modeled using similar means as A-to-B ballistic missile targeting analysis. For a given morphologic feature of interest (suspected ejecta, point B), this analysis allows correlation of the governing transport to suborbital mechanics, and identification of possible crater or impact structure location point A.

First, the launch state must be estimated, including the location (lat/long), direction (elevation and azimuth or EL/AZ) and velocity (VEL) of the launch. The launch location is a supposed parent crater, impact structure, or region. An A-to-B transport trajectory is derived using suborbital mechanics. For a rotating planet, this is an entire family of A-to-B trajectories, each with unique Time of Flight (TOF) as point B moves over time.

Variation of VEL and EL demonstrate the principal downrange direction at the fall site B or morphologic feature, while variation of AZ indicates the principal cross-range direction. In order to match the clocking or alignment of these principal directions with axes or features observed in the imprint, launch location is varied relative to the fall point.

Next, a perturbation of the ejecta outflow is assumed. This involves transverse ΔVEL applied to the primary transport trajectory. A series of perturbed trajectories are generated by applying slight AZ and EL variations in a circle around the primary trajectory, making a cone of perturbed trajectories. The slightly different tangential component of each perturbed trajectory displaces its corresponding fall point, defining a mapped shape around the unperturbed fall point.

If the mapped shape from suborbital perturbation duplicates the observed imprint, possible suborbital transport involvement is indicated. Mathematical comparisons of the perturbation map shape to the imprint morphology provide numeric correlation coefficients.

Ideally, this process is applied to multiple, regionally distributed morphological cases with various axial alignments, where each case is a possible ejecta emplacement. Similar or identical calculated launch locations from different emplacement locations provide further correlation coefficients. Repeated mapped shape correlations and launch location correlations indicate strong likelihood of suborbital transport.

  • SUBORB OBSTRUCT SHADOW GSA2015 Harris Small.pdf (10.9 MB)
  • Suborb Obstruct Shadow & Transport Imprint Matching XML 2015 GSA Baltimore Handout THSHarris.pdf (284.9 kB)
  • SUBORBITAL ANALYSIS FRAMEWORK Final To Print Harris GSA 2015 Frame 1 of 2.pdf (490.1 kB)
  • SUBORBITAL ANALYSIS FRAMEWORK Final To Print Harris GSA 2015 Frame 2 of 2.pdf (1.2 MB)