Rapidly multiplying space debris threatens America’s information-based economy, scientific research, space exploration, and intelligence assets. Even a small screw can disable a multi-billion-dollar satellite if they collide at orbital speeds. Researchers lack the necessary knowledge about most orbital objects to confidently predict if a collision will occur, how to avoid it, and what debris will result from the collision. Even if a warning is issued, the false-positive rate is cripplingly high. Livermore’s Testbed Environment for Space Situational Awareness (TESSA) seeks to mitigate orbital collisions and resulting space debris by demonstrating methods for improving the accuracy of scientists’ orbital knowledge.
TESSA is a modeling and simulation environment developed by LLNL researchers to simulate the tracking of satellites and space debris with ground- and space-based sensors. TESSA includes capabilities for predicting the future location of a satellite using the satellite’s current location and velocity, determining an object’s orbit from sensor data, finding new orbital objects, predicting close approaches, determining the probability of collisions, modeling various sensors, and modeling debris generation.
TESSA works by linking modules simulating individual pieces of an observation network, such as telescopes and computers, with a parallel discrete events simulator that allows orbit propagation and determination algorithms to run in parallel. This feature enables the tool to simulate hundreds of thousands of objects in orbit. The software is optimized for deployment on a large cluster of high-performance computers running Linux and also includes a scalable visualization environment implemented as a post-processor on workstation-class platforms.
TESSA has demonstrated that it can be used to quickly and cheaply evaluate new space technologies. Unlike most sensor simulators, TESSA’s sensor modules do not rely on statistical or empirical models; they simulate the physics of the sensor. A user can therefore accurately simulate nearly any new kind of radar or telescope just by setting a few physical parameters in the configuration file. TESSA has also been used to demonstrate new experimental algorithms, including a high-performance module for detecting close approaches between orbiting objects, a method to calculate the possibility of collision, and a method to quickly locate a maneuvering satellite.
TESSA has already inspired a research effort to deploy a constellation of cheap mini-satellites to track orbital debris. If such a project can successfully reduce the number of in-orbit collisions, TESSA may help save billions of dollars in satellites, as well as improve manned mission flight safety.
For more information, contact Alex Pertica.
Preventing Close Encounters of the Orbiting Kind, Science & Technology Review, July/August 2009