What goes up must come down. It's a true statement, but the missing argument of the equation is when? Ever since the Russians launched the first Sputnik in 1957, the United States and Russia have been launching satellites into low, medium, and geosynchronous orbits. In the past thirty years the proliferation of man made satellites in orbit has been further intensified buy other countries getting involved in space. The profusion of satellites and space junk floating around up there is becoming a serious hazard to all orbital space craft including the Hubble Space Telescope (HST), space station, space shuttle, and not to mention, hundreds of vital communications and navigation satellites.
On January 18, 2007, the Chinese successfully destroyed a satellite in polar earth orbit as part of an antisatellite capability test. The event produced a debris field consisting of an estimated 40,000 pieces. The United States halted similar types of tests in 1985, specifically to avoid creating such debris fields. A year later the U.S. destroyed an ailing spy satellite in orbit. But the most alarming incident may have occurred on February 10, 2009, when two Russian satellites accidentally collided in space.
The Iridium 33 intersected the orbital path of the and Cosmos 2251 over Siberia. The two satellites had an estimated closing velocity of 15,000 miles per hour and produced two large debris fields raising concern among space agencies around the globe. A software company called AGI Graphics produced an animation of the Ierridium/comos collision which demonstrates the scope of the debris problem. You can view it at: http://www.youtube.com/watch?v=GF8DVdj6rzw as well as at other locations around the web.
As a result of this most recent event, and the increasing threat to Americas assets in space, the United States Air Force's Space Command (AFSPC) was tasked with stepping up its space junk surveillance program and space traffic control capabilities referred to by the Air Force as the Space Situational Awareness (SSA) mission. The Air force already uses UHF radar to track space debris as small as an inch and a half, but the profusion of bits, pieces, and parts continues to grow in number, and cataloging and tracking it all is becoming a gargantuan task. Keeping space craft from colliding as demonstrated by the Iridium/Cosmos event is a prime concern. Recently the Air Force began to research new ways to accomplish its SSA mission.
One existing facility the Air Force has identified which could be used to track satellites transmitting radio signals, is the Alan Array Telescope (ATA) located at the Hat Creek Radio Observatory (HCRO) in Northern California. The facility is a joint project of the SETI Institute and the University of California at Berkeley's astronomy department. Eventually the array will consist of 350 20-meter dish antenna's operating in the .5 to 11 GHz (Giga-Hertz) part of the electromagnetic (EM) frequency spectrum, but currently only 42 of the dishes are installed and operational. The primary source of funding to build what exists of the ATA came via a grant from Microsoft co-founder Paul Alen, but SETI is in need of an infusion of cash before construction of the ATA can continue. If the Air Force can use the facility to track satellites, perhaps some of that funding will come by way of a grant from the Department of Defense (DOD), but considering the current budgetary constraints, its not likely that any disbursements can be expected in the near future.
In this time of economic hardship for many Americans, it may seem unjustifiable for the American government to be investing in projects like the ATA, but this kind of thinking may be extremely short sited and have much greater long term costs. Today, satellites are an integral part of the United State's defense strategy, the backbone of its communications infrastructure, and essential element of air navigation and air traffic control facilities. Consider the potential the Chinese have already demonstrated to destroy satellites and then ask yourself why? Consider the fact that North Korea, China's close ally, is desperately trying to develop its own Inter Continental Ballistic Missile (ICBM) capability, not to speak of a nuclear arsenal. The Chinese may be our global trading partners, in so far as they want and need to exploit our market place, but the same government that extends its hand to American businesses is supplying terrorists with the weaponry that is killing American military personal in Iraq and Afghanistan. It is providing the weapons being used to conduct genocide in Africa, and the scud missiles used by Saddam Hussein to great effect in the first gulf war, and which the Iranians are now attempting to modify for use as a medium rage delivery capability.
Make no mistake about it, space really is the final frontier and it is also the most likely battle ground where future conflict may erupt. The United States Air Force currently has the only capability, limited as it is, to track space debris and provide space traffic control. If the Air Force's SSA mission can benefit from use of the existing ATA facility and perhaps even fund the completion of the project, not only the SETI institute and U.C. Berkeley Astronomy Department will benefit, but the citizens of the U.S. and the world, may just have a safer planet to inhabit.
Setting aside the more prolific implications of humans and their machines above the atmosphere, the monitoring and control of satellites by the Air Force using the ATA could prove its worth by preventing another instance such as the Iridium/Cosmos collision. The cost involved with the loss of a single communications or navigation satellite would far outweigh any investment the DOD might make in the ATA and other facilities which could be used to prevent it. Furthermore, the scientific benefits which can be achieved by full development of the ATA facility could be absolutely profound. Radio Astronomers are already using the ATA to study the phenomena of Black Holes, and the SETI Institute, the existence of planets around other stars and potential of intelligent life on them. Perhaps the alliance of a government agency, academic institution and private organization could become a model for more efficient use of tax payer funding in the future. When you add it all up, the Air Forces collaboration with SETI and U..C. Berkeley to share the ATA facility may have a lot of pluses.