The gun pointed at the head of the universe
by Dwayne Day
|During last month’s Hubble repair mission, the shuttle Atlantis faced its highest ever risk of being destroyed by space debris—not simply impacted, but actually severely damaged.|
The first speaker at AIA’s symposium was Paul Graziani, President and Chief Executive Officer of Analytical Graphics, Inc. AGI produces sophisticated graphics software that is used by various customers—and frequently shown on television and the web—to display objects in orbit, from single spacecraft to clouds of killer debris. As Graziani spoke, he played various computer animations and charts and graphs on a big screen behind him, illustrating the tremendous growth in the space debris population over the years.
Graziani said that there are currently 19,000 objects larger than a softball in orbit. Those are the ones that can be tracked from the ground. The more dangerous population includes the objects between 1 and 10 centimeters, which are too small to track, but big enough to cause serious damage to a spacecraft. There are an estimated 300,000 of these killers currently in orbit, each one capable of smashing into the space shuttle, the International Space Station, or any of hundreds of active robotic spacecraft. As far as objects smaller than 1 centimeter goes, nobody has a good idea of how many are up there, but most estimates are in the millions. Space might be a big place, but low Earth orbit isn’t all that big, and it’s filled with a lot of junk.
Graziani added that several “incidents”, starting with the January 2007 Chinese ASAT test, and most recently the February 2009 collision of an Iridium comsat and a retired Russian spy-communications satellite, have added substantially to the debris population. For example, the Chinese ASAT test added 2,500 pieces larger than a softball to low Earth orbit. In this regard the Chinese ended up polluting their own backyard, since they also use the orbit that they’ve filled with debris. “They’ve got a manned space program of their own and they’re going to have to deal with the results of that debris,” Graziani explained.
He then contrasted China’s actions to those of the United States, which destroyed the defective USA-193/NROL-21 intelligence satellite in February 2008. That event was conducted in such a way as to minimized the generation of debris. (Various AGI animations of the incident can be downloaded here.) “When we do things in space,” Graziani said, “we do them very responsibly.”
The Iridium incident, although adding substantially to the debris population in low Earth orbit, has had an unexpected side benefit. The radar systems that the United States currently uses to track objects in low Earth orbit can only calculate the location of objects to an accuracy of several hundred meters. The Iridium and Russian satellites were supposed to pass no more than 584 meters from each other. But because they hit, it demonstrated the locational limitations of the tracking systems. Graziani listed three overall limitations to American tracking systems:
There are a number of things that the United States could do to improve the situation, Graziani said. These include developing more and better sensors, and partnering with satellite operators and other countries that can provide data on the precise locations of their satellites.
The person with responsibility for actually doing something—America’s chief of orbital sanitation, so to speak—was next up at the lecturn. Dr. Andrew Palowitch is the first director of the newly created Space Protection Program, which is jointly sponsored by the US Air Force and the National Reconnaissance Office. He said that he felt that in some ways he is uniquely qualified for the position. He had previous CIA experience, but it is his background as a submarine officer that gave him an appreciation for the importance of space systems. Palowitch served on the USS Parche, a Cold War spy sub that conducted numerous highly classified—and likely highly dangerous—missions. “Those critical missions were fully enabled by satellite operations,” Palowitch said, without going into any details.
|Gen. Petraeus “has less concern about optical over China, less concern over intelligence systems in geostationary…” Palowitch explained. What Petraeus cares about is his ability to communicate with his people in the field, Palowitch said, and that requires a French comsat.|
Palowitch said that when he first became director of the Space Protection Program, he asked various people if there was a list of all of the critical satellite systems and was surprised to learn that “there was no comprehensive understanding of what… the critical satellite systems were.” So he had some people start compiling a list and they ultimately came up with over 350 satellites that were considered “critical.” These were not simply American military and intelligence satellites, but also included a substantial number of civil and commercial satellites, as well as those operated by America’s friends and allies. For example, over 95% of the international communications of the Department of Defense are transmitted over commercial transponders.
Palowitch told how General David Petraeus, commander of Central Command and responsible for American forces in the Middle East and part of Asia, was asked what was the most vital satellite that his command uses. Instead of naming a missile warning satellite, or a spysat, or GPS, Petraeus named a French communications satellite. “He has less concern about optical over China, less concern over intelligence systems in geostationary…” Palowitch explained. What Petraeus cares about is his ability to communicate with his people in the field, Palowitch said, and that requires a French comsat.
But it’s not just the United States that relies upon other countries. On May 12, the French contacted the US government about one of their SPOT imaging satellites that was going to come dangerously close to another space object, an event known as a “conjunction.” According to Palowitch, it took five to six hours just to arrange a discussion between the two countries’ space officials about the close pass so that the Americans could share their tracking data and the French could decide whether to move their satellite. Although he did not elaborate, nor did he say what object the SPOT might hit, clearly some method has to be developed so that such coordination becomes faster. Even if the SPOT was not in danger of hitting an American satellite, the United States would suffer from any collision.
Of course, the question that everybody wants to know is what the United States can do about the orbital debris problem. Palowitch said that the strategy for addressing the orbital debris problem can be summed up in three things: prevent debris; avoid it; and clean it up. For a long time the United States’ primary focus has been preventing debris. Now that there’s so much up there, we’re placing greater emphasis on avoiding it.
Palowitch said that there have been eight known collisions in space over the years. He said that his view is that within the next ten years, there will be at least ten more. Even if we do our best, the situation has reached a tipping point and things are only going to get worse. [Author’s note: I may have made a mistake and he might have said five years instead of ten.]
“As large as space is, there are very, very few spots” to place the satellites, Palowitch said. This is compounded by the fact that America’s adversaries also deliberately park in some of these orbital slots and may also maneuver their satellites so that their frequencies interfere with those of a rival.
|Palowitch said that the strategy for addressing the orbital debris problem can be summed up in three things: prevent debris; avoid it; and clean it up.|
Palowitch’s office is currently sponsoring a study by several aerospace contractors about cleaning up orbital debris. They are looking at the region from low Earth orbit up to around 800–900 kilometers. But there are several difficulties to developing any cleanup scheme. The first is that this is not really recognized as a problem, particularly when compared to more pressing and obvious Department of Defense needs. The second problem is what Palowitch called “the technological piece”—in other words, developing new technologies to deal with the problem. The third issue is that any solution has to be an international consortium or it will not work.
In response to a question about how one would actually go about removing debris, Palowitch laughed and said “You know, I got in trouble for this…” and did not elaborate. He directed people to an article on the subject in Aviation Week and then mentioned one unclassified concept for using a ground-based laser to ablate the surface of objects in low Earth orbit, inducing drag and causing them to fall from the sky earlier. But when talking about using powerful lasers to affect satellites in low Earth orbit, “it becomes very touchy,” he conceded, and such a system would require careful international coordination. He implied that the study currently underway might include several classified concepts for removing orbital debris.
Another person asked about the current level of effort in the United States for dealing with space protection. Palowitch noted that in the past year Congress has put $3.2 billion into the issue, and over $5 billion in the last seven years. But Palowitch said that substantial infusion of cash in recent years comes after a long and steady decline, so there’s no reason to expect the situation to improve in the immediate future. Meanwhile, the amount of debris in orbit is increasing.
Another member of the audience asked about the barriers to remediating the problem and asked if there are commercial companies that will remove debris for a fee. Palowitch said that he is practically deluged with industry proposals. There are companies interested both in removing debris and satellite relocation at the end of their useful lives. The problem is not a lack of ideas, it’s more bureaucratic—a lack of a clear policy on what to do, as well as the complexities of international law. Plus, of course, the “cost barrier.” Who’s going to pay for the cleanup?
Palowitch concluded by noting that there are three exercises underway that may tackle the issue. President Obama signed Study Directive #3 calling for a review of the National Space Policy (which proved so controversial when it was released by the Bush administration a couple of years ago). The Department of Defense is also undertaking a “Space Posture Review.” And finally, the DoD is conducting its Quadrennial Defense Review. While these three are underway, the State Department, assisted by NASA, is also working with the Committee on Peaceful Uses of Outer Space in the United Nations.
But while the studies continue, and the bureaucrats debate, silently overhead millions of pieces of space junk hurtle along, waiting for an opportunity to kill something—a robotic spacecraft, a human spacecraft, or the space station. The physics are immutable, and nasty.