Many vision systems capture high-speed images, but perhaps none do quite so as quickly as the one developed by UK-based Specialised Imaging (Tring, UK) for imaging fast-moving micrometeorites at the White Sands test facility's remote Hypervelocity Test Laboratory in Las Cruces, NM.
In the laboratory setup, a two-stage light gas gun launcher uses highly compressed hydrogen to accelerate projectiles at velocities in excess of 7.5 km/s (16,800 mi/h) toward a target to simulate the impact of particles on spacecraft and satellite materials and components.
To capture images of the high-speed projectiles as they hit the target, the system produced by Specialised Imaging employs the company's own SIMX8 camera that has been programmed to acquire an eight-frame sequence of events prior to and during impact of the micrometeorites.
In the development of the system, it was critical that the timing of the arrival of the micrometeorites was extremely accurate so that the camera -- and a xenon flash used to illuminate the target -- could both be triggered to coincide with the arrival of the projectiles prior to impact.
The system employs two separate laser beams whose paths are interrupted at different times by the particle as it travels toward the target. The difference in those times can be used to provide an accurate calculation of the velocity of the particle and also a means by which the system can calculate the moment that the camera and the xenon flash should be triggered.
Using the new system -- which replaced an older film-based system -- the White Sands researchers are now able to routinely capture different sequences of images to examine the effects that high-speed particles might have on spacecraft structures.
-- Posted by Vision Systems Design
