Many times I wonder what comes first in regards to NASA acronyms, the ultimate chicken and egg question. This month’s Reaching Orbit is a great example of this quandary. The Synchronized Position Hold, Engage, Reorient, Experimental Satellites (SPHERES) is undergoing a new experiment called the Visual Estimation and Relative Tracking for Inspection of Generic Objects (VERTIGO). See, I wasn’t kidding. Despite the acronym overload, the experiment itself is very interesting.
To begin, the SPHERES experiment involves the use of three sphere-like satellites. These are not what you would normally imagine when you think of satellites as they are orbiting the Earth only in the sense that they are flying aboard the International Space Station (ISS). These three stooges fly inside the ISS performing flight formations and docking maneuvers. SPHERES is a test bed for a number of algorithms related to satellite flight including collision avoidance, attitude control, re-targeting and fuel balancing. Basically, it allows for testing of maneuvers in microgravity, serving as a miniature test ground with low cost and chance for loss of expensive instruments due to failure in space.
VERTIGO is an experiment that takes advantage of the SPHERES’ capability, giving the satellite a set of eyes. The intention is to equip the satellite with the ability to visualize its surroundings, to create a 3-dimensional model of an object in microgravity. While I’m sure it was strange to watch polyhedron spheres maneuvering in the ISS, spheres with eyes borders on the surreal. Like something out of a sci-fi movie or possibly an animated film, it’s reminiscent of Hal in a Wilson disguise. The set of eyes allows VERTIGO to essentially create stereo images that are then processed into a 3D model. All of the algorithm processing and data crunching happens within the VERTIGO goggles which are basically a small laptop computer. VERTIGO consists of two SATA flash drives, two wireless antennas, a control panel, an ISS Nikon battery, a detachable optics mount with the added advantage of an avionics stack.
The intention of the VERTIGO experiment is to allow the SPHERES to maneuver based on their surroundings, not just programmed flight paths, giving them the ability to process their environment and navigate accordingly. VERTIGO can also be used to image objects in space that are difficult if not impossible for astronauts to investigate safely. VERTIGO technology would allow free-flying satellites to get ‘up close and personal’ with objects like asteroids and to map their surfaces with reduced cost and danger. The VERTIGO experiment has just undergone its first tests aboard the ISS and has performed adequately for its first time out. Pretty ‘neat-o burrito’ in my book!