COLORADO SPRINGS, Colo. — Take all of Earth’s air space that is used by conventional aircraft and multiply that 6,000 times. That’s is the area the Air Force needs to monitor to have a complete picture of what is happening to the thousands of orbiting systems that circle the planet.
A Chinese anti-satellite test more than two years ago gave the service a renewed focus on the field of “space situational awareness.”
On Feb. 10, the Air Force failed to predict the collision of two communications satellites in low-earth orbit. A Russian Cosmos spacecraft slammed into an Iridium satellite at a speed of seven-kilometers per second. The accident further reinforced the need for better space surveillance, Air Force officials said at the Space Symposium here.
Programs that will give the military a better idea of what is happening to its high-priced spacecraft — and those of potential foes, and more benign commercial and scientific operators — are in the works. Contractors confirmed that there are classified efforts underway in the “space protection” realm as well.
Meanwhile, some unclassified programs are being pursued. That includes a spacecraft awaiting launch that will be able to inspect satellites in geo-synchronous orbit — roughly 24,000 miles above the Earth (see accompanying story).
The current space situational awareness system, which uses ground-based radar, dates back to the Cold War and “works pretty good for what it does,” said Vice Adm. Carl V. Mauney, deputy commander of U.S. Strategic Command.
However, the military needs to “know what the intentions of adversaries are, and must be better able to predict close calls,” he said. “Especially in low orbits where there is more traffic and more debris.”
The Iridium-Cosmos collision provided an example of how the Air Force must deduce what is occuring in space since it doesn’t have a direct view of what’s happening there.
Lt. Gen. Larry James, commander of the 14th Air Force Wing and Stratcom’s joint functional component command for space, said the first indication that something was wrong was a simple message from the Iridium satellite that it was no longer functioning. Temporary malfunctions are not uncommon, but staff at the joint space operations center at Vandenberg Air Force Base, Calif., carried out a routine analysis.
“No one knew what had occurred. There was no indication of what happened except the satellite was not working,” he said. The Air Force uses a series of ground-based radars — the space surveillance network — to track objects. In this case, radar showed multiple objects orbiting where there should have only been one. After about 45 minutes, analysts at the center determined that there had probably been a “conjunction,” which is Air Force-speak for an on-orbit collision. An analysis pointed to the Cosmos military satellite as the probable cause.
James said the center tracks about 19,500 objects every day. Some of these are working satellites — others fall under the “space junk” category: spent rockets, dead spacecraft and debris from collisions.
Prior to the accident, the center did about 130 “conjunction assessments” per day to determine if any of these objects were on a collision path. Since then, the Air Force has pulled personnel off other jobs to do an additional 200 such assessments each day, James said.
“Frankly, we don’t have the sensors that we need,” he added. The ground radars are a legacy of the Cold War and were initially designed to warn the United States of Soviet missiles coming from the north. Consequently, the sensors are concentrated in the Northern Hemisphere.
“Payloads that fly to the south; we don’t see them very frequently and we don’t see them right away,” James said.
Space situational awareness encompasses much more than tracking objects, James added.
When another nation launches a satellite into space, the Air Force wants to know what it is, where it will travel, what its capabilities are and the intentions of its owner. “Not just know that it is at position X,” James said.
The Air Force has helped organize the commercial foreign entity working group, which will help it collect data from operators of non-military spacecraft such as communications satellites. It is also currently studying what it wants its future space situational awareness architecture to look like.
Meanwhile, the list of space-faring nations is growing. The proliferation of so-called nano-satellites, or cube-sats, is also a concern, he said. This new generation of spacecraft can be as small as a pack of cigarettes.
“How do we track those? How do we know what their intent is?” James asked. “Something going 11,000 meters per second can do a lot of damage even if it is the size of a pack of cigarettes,” he added.
Gen. C. Robert Kehler, commander of Air Force Space Command, said the collision caused the service to go back and look at the way it is carrying out its assessments.
“We keep that catalog up to date, but we do not watch everything for collision purposes all the time,” he said.
The February incident was the third known case of an on-orbit collision, but the first in 22 years. In December 1991, a Cosmos satellite collided with debris from another member of its constellation. In July 1996, a piece of a European Ariane rocket damaged a French satellite. As recently as March, the crew of the international space station was forced to take refuge in an escape pod as a piece of space debris came perilously close.
Kehler said there needs to be more formal data sharing agreements between the Air Force and other entities such as commercial satellite companies.
Space has been described as an enormous 3-D chess match.
“We do not have the luxury of simplifying the problem by focusing on one geographic part of the Earth at a time,” Kehler said.
Meanwhile, the State Department is talking with other nations to help solve the problems of orbital debris and a lack of situational awareness in space, an official who spoke to reporters in Washington said. He asked not to be named.
The department has an office of space and advanced technology, which is attempting to make other nations adopt “best practices” for their space platforms.
Space weather is a large part of this. Solar flares can knock out a satellite, and there are currently few on-orbit sensors that can monitor the sun’s activity, he noted. Without this knowledge, operators may not know if the loss of a spacecraft is a natural phenomenon, something more sinister or just a malfunction.
The European Space Agency recently has come to the conclusion that space situational awareness is a problem, and it wants to make its systems more robust. State is working to make sure that efforts aren’t duplicated and that data can be shared, the official said.
The European Union is helping the United States draft a “code of conduct.”
That might be ensuring that old satellites are moved into safe orbits once they reach the end of their lifespan. In the case of expendable rockets, vents should be placed in tanks that allow unspent fuel to escape. Otherwise, the sun heating up the metal can cause the fuel to explode, thus creating more space debris.
But he admitted, that these space agreements aren’t enforceable.
“You can’t take someone to the intergalactic court to sue,” he said.