SAN FRANCISCO — The U.S. Department of Energy’s national laboratories are using sensors and modeling expertise developed during decades of nuclear treaty monitoring to augment U.S. Air Force efforts to characterize the space environment and mitigate the danger posed by orbital debris.
“There isn’t enough money to build new capabilities from whole cloth,” said Jeffrey Bloch, program manager for space situational awareness at the Los Alamos National Laboratory in New Mexico. So the laboratories are contributing their expertise in materials science, space environmental sensing, high-performance computing and hypervelocity impacts to Air Force efforts to improve space situational awareness, he said.
In recent years, particularly in the wake of the early 2009 on-orbit collision that destroyed an Iridium communications satellite, U.S. military officials have highlighted the importance of protecting government and commercial satellites from orbital junk and from other spacecraft. The Air Force currently tracks more than 20,000 objects in space, but there are “probably 10 times more objects in space than we are able to track with our sensor capability today,” Gen. William Shelton, commander of U.S. Air Force Space Command, said April 12 at the National Space Symposium in Colorado Springs, Colo. Objects that cannot be tracked can nonetheless be lethal to operational space systems, he said.
To reduce the threat those objects pose to U.S. satellites, Air Force officials have called for development of a more sophisticated network of ground- and space-based sensors capable of sharing information, analyzing that information and feeding it into military command and control systems. Department of Energy laboratories are conducting a number of projects aimed at helping the Air Force create that network, Bloch said.
One of those efforts employs the powerful supercomputers used to model nuclear weapon explosions. Physicists and engineers at the Lawrence Livermore National Laboratory in California have created a set of modeling and simulation tools to show the debris produced when an orbiting satellite collides with another object in space.
The work, initiated in 2008, was used to map the debris cloud created when a retired Russian Cosmos satellite collided with an Iridium Communications spacecraft. Livermore scientists were able to create a model of the debris cloud within days, providing Air Force officials with information to assist them in evaluating the risk that debris posed to other satellites, said Scot Olivier, associate division leader for applied physics at the lab.
Since then, the Livermore team has continued to refine those models and to craft plans to give the U.S. Defense Department’s Joint Space Operations Center (JSPOC) at Vandenberg Air Force Base in California the tools to conduct its own analysis of orbital collisions. Under the plan, Livermore teams would conduct initial modeling work on the Department of Energy supercomputers, extract information obtained and put that data into a format that could run on JSPOC’s computers, Olivier said.
In the future, Livermore researchers hope to provide JSPOC with a direct link to the laboratory’s high-performance computers. With remote access to a Livermore supercomputer, JSPOC operators would be able to run their own detailed simulations in the wake of spacecraft collisions, Olivier said.
In a parallel effort, Livermore physicists and engineers have created models to represent the current Air Force Space Surveillance Network, which relies primarily on ground-based radars and telescopes around the world to detect and track objects in space. By analyzing those models, Livermore researchers determined that the Air Force could gather data on orbital debris from collisions more quickly by pointing sensors at the densest part of the debris cloud.
“For the Cosmos-Iridium collision it took about six weeks for the JSPOC operators to find, identify and track the pieces of debris they could see,” Olivier said. Livermore models showed that by modifying sensor schedules to focus instruments on the debris cloud in a manner that gives the highest priority to areas with the greatest concentration of objects, operators could have found and tracked that debris in less than a week, |he said.
Another effort at Los Alamos focuses on using the space-based sensors the Department of Energy uses to monitor nuclear treaty compliance to improve military space situational awareness. As part of its nuclear detection job, Los Alamos uses ground- and space-based sensors to monitor space weather and characterize the space environment. That monitoring is an essential component of nuclear threat detection because it prevents Department of Energy officials from waking up the president in the middle of the night after confusing an intense solar storm with the effects of a nuclear explosion, Bloch said.
Los Alamos officials are working with the Air Force to investigate ways the Department of Energy could use the sensors designed to detect nuclear detonation to improve space situational awareness and space protection. Government agencies “can’t afford to build their own monolithic systems that serve only one mission,” Bloch said. “Data sharing and capability sharing is the way of the future in this cost-constrained environment.”
Sandia National Laboratories and the U.S. Air Force Research Laboratory also are conducting studies to improve military space situational awareness. The Air Force Research Laboratory is developing technologies to bolster the JSPOC’s ability to assess the risk of satellite collisions and to improve space-weather monitoring, Air Force spokesman Michael Kleiman said in an emailed response to questions.
Sandia officials are developing computer simulations to predict the effect on satellites of orbital collisions and to determine the direction resulting debris will travel. Accurate predictions of how that debris moves are important because they can help government officials determine which spacecraft will be threatened by the debris, Steve Gianoulakis, architectures and infrastructures manager for Sandia National Laboratories in Albuquerque, N.M., said in an emailed response to questions.
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