Photogrammetry and ballistic analysis of a high-flying projectile in the STS-124 space shuttle launch

Abstract

A method combining photogrammetry with ballistic analysis is demonstrated to identify flying debris in a rocket launch environment. Debris traveling near the STS-124 Space Shuttle was captured on cameras viewing the launch pad within the first few seconds after launch. One particular piece of debris caught the attention of investigators studying the release of flame trench fire bricks because its high trajectory could indicate a flight risk to the Space Shuttle. Digitized images from two pad perimeter high-speed 16-mm film cameras were processed using photogrammetry software based on a multiparameter optimization technique. Reference points in the image were found from 3D CAD models of the launch pad and from surveyed points on the pad. The threedimensional reference points were matched to the equivalent two-dimensional camera projections by optimizing the camera model parameters using a gradient search optimization technique. Using this method of solving the triangulation problem, the xyz position of the object's path relative to the reference point coordinate system was found for every set of synchronized images. This trajectory was then compared to a predicted trajectory while performing regression analysis on the ballistic coefficient and other parameters. This identified, with a high degree of confidence, the object's material density and thus its probable origin within the launch pad environment. Future extensions of this methodology may make it possible to diagnose the underlying causes of debrisreleasing events in near-real time, thus improving flight safety.

A phenomenological relationship between vertical air motion and disdrometer derived A - b coefficients

“…These measurements included the ejection angle of the dust above the lunar surface, the velocity of the blowing rocks (since the smaller particles were not individually discernible from that height), and the quantity of eroded soil (estimated by analyzing the terrain scouring beneath the Lunar Modules after landing) (Immer et al, 2011b;Metzger et al, 2011). The drag forces from the software also accurately measured the blowing of foam debris in an anomalous launch pad event in the Space Shuttle launch environment (Metzger et al, 2010), and it was used to identify the size and origin of a falling rock that nearly struck a skydiver at high altitude (Metzger, 2014).…”

In situ disdrometer calibration using multiple DSD moments

“…In the current method an additional laser extinction term is included in the Kasparis error minimization, as shown by Equation ( 7) and ( 15). Using the mathematical notation and computational approach of Metzger et al (2010), the error function minimum can be easily found for a given . The Metzger notation provides a convenient and compact form, easing evaluation complexity, where a simple matrix inversion solves the problem directly.…”