The views expressed are those of the author(s) and are not necessarily those of Scientific American.
The U.S. Navy has successfully shot down NROL 21 (aka USA 193), the crippled and covert National Reconnaissance Office (NRO) satellite. (See SciAm's slide show here.) Whereas skepticism was voiced by some, the mainstream media outside of the science and technology press largely went along with the U.S. Defense Department's official line that it had to prevent 1,000 pounds (450 kilograms) of toxic fuel from polluting the atmosphere or bombing someone's backyard. So, with a wink, we could all get that cozy Kumbaya feeling knowing U.S. military might had been unleashed for the good of the environment, and the greener future of little children and baby seals everywhere. But although much of the mainstream coverage debated the international political ramifications of this event, they missed, or ignored, its clandestine aspects. USA 193 is hardly the first errant satellite or rocket booster to tumble out of orbit carrying toxic fuel or other substances that may foul the atmosphere, and any falling space junk can do harm if it impacts on a populated areaâ€”but the problem, albeit serious, is local, rather than global in scale. Here is the Defense Department's official line, found in Aviation Week: According to Marine Gen. James Cartwright, the dead satellite's full tank containing 1,000 pounds of frozen hydrazine poses enough of a danger to warrant the Navy's action. He says the active response is necessary because the tank will probably survive reentry. If it landed on a populated area, a plume of lethal gas, similar to chlorine or ammonia, could spread 20 to 30 yards. He also notes that the U.S.'s action in shooting down the satellite differs from the last year's Chinese test in that all international parties were notified and that the Navy waited until the spacecraft's low altitude would allowed all the debris from its destruction to fall out of orbit. The DOD's ostensible concern with pollution resulting from hydrazine maneuvering fuel on board, however, could be suspect, as pointed out by Theodore Postol, a professor of science, technology and national security policy at the Massachusetts Institute of Technology and a former science adviser to the Navy, in an interview on PBS's February 20 News Hour: "I don't think the idea has any technical merit. What you have is a vehicle that's in space. It's built as light as it possibly can be, because it's a satellite designed to just be in space. When this thing hits the upper atmosphere, large pieces of it are going to burn up. Now, there will be big pieces that survive to the ground, but the idea that this hydrazine tank will survive to the ground really makes no sense. Let me just give you an example. This hydrazine tank is going to decelerate at a rate ofâ€”let me just use the numbersâ€”50 Gs. I just did the calculations before the program. What that means is I take this spherical hydrazine tank and I accelerate it from rest to 1,000 miles per hour in one second. Now, this gossamer tank, this spherical tank is going to squash up and break open. And it's going to beâ€”the hydrazine is going to behave like a snowball fired out of a cannon. It's just going to spray all over the place, stop in the upper atmosphere probably at an altitude of 60 or 70 miles, and it's never going to reach the ground. There will be pieces of the satellite that reach the ground, but the hydrazine is never going to come close to the ground." So why the need to hurry this particular satellite's demise? It seems that there are two other reasons why the administration, the NRO and the Pentagon may have found it in their interest to destroy USA 193." A Nature magazine article (Experts suspicious of "splatellite" plan), framed the event in terms of the emerging arms race between the U.S. and China, and our attempt to respond to China's misguided and messy demonstration of their own satellite-killing ability in January 2007. China, along with Russia, purportedly wants a ban on any further space weapon testing, and may be trying to demonstrate the consequences of the Bush administration's current policy that has shunned any halt. Conversely, maybe China is secretly glad the U.S. wants to get it on in space, which, if true, would bode ill for our ability to function in low Earth orbit. (Another viewpoint on why it is a bad idea to start shooting down satellites can be found here.) Shooting this satellite-gone-bad out of the firmament (actually it was hit with a nonexplosive impactor) therefore might have seemed like a good idea to the Bush administration and Pentagon because it was the perfect chance to run a test demonstrating our intent testing, and by doing so, brag on our technological superiority. Also it was a favorable situation because earlier higher orbit satellite-kill tests by the U.S. and Soviet Union from the 1960s to the 1980s had created orbiting debris fields, as did the more recent Chinese test when they recklessly took out one of their own, obsolete weather satellites at an altitude of around 525 miles (850 kilometers). Space flotsam from weapons tests and other sources has proved hazardous to satellites as well as manned vehicles, such as the International Space Station and space shuttle, and it lasts for decades, if not longer. Fragging USA 193, (at around 150 miles, or 240 kilometers) not long before it dropped low enough to plow into the decelerating friction of Earth's atmosphere would, however, not be "littering" orbital space, as 50 percent of the dross is predicted to plummet to Earth within two orbits, with the rest coming down within a month. (Not all experts agree with this; some argue, according to the Nature article, that the explosion could hurtle debris back into a higher orbit.) Even if the Navy's strike will have proved itself successful in bringing this bus-size 2,250-kilogram albatross down "clean," this low-altitude hit will not have necessarily demonstrated our ability to knock out satellites in their operational altitudes. It is, however, the first time a tactical surface-to-air missile has been used to attack a satellite. And, not unimportantly, the incoming vehicle mimicked an incoming warhead. So, hydrazine or not, could it be that what could have been a public relations nightmare for the NRO became a golden opportunity for the Pentagon: Under its mostly accepted green public relations patina, the military was received a gift: a missile defense system test under real-world conditions. Speaking of turning a liability into an asset: brilliant. But could there also have been an additional (or maybe the primary) reason for this actionâ€”one not widely discussed by the mainstream press, probably because of the covert nature of USA 193, which makes it hard to glean any verifiable information. Did USA 193 carry a cargo of secrets? Cartwright expected 2,500 to 2,800 pounds of the vehicle to survive the fires of reentry. The satellite's orbital inclination of 58.5 degrees, suggested it was that of a surveillance satellite, with coverage that included a large swath of Eurasia. Hence, if it had crashed on land, there is a chance it could have landed on Russian, Chinese or other non-U.S.-controlled territory, perhaps delivering intelligence manna chock-full of charred clues to our latest eye-in-the-sky gadgetry. According to GlobalSecurity.org, the satellite might have held a new space radar. Its launch in December 2006 on a Delta 2 from Launch Complex 2 at Vandenberg Air Force Base in California was managed by the NRO. Launches from Vandenberg are usually polar or high-inclination orbits, preferred for reconnaissance missions. The details of the satellite's contents are secret, but the site speculates that it may have carried Future Imagery Architecture (FIA) imaging radar that may be a replacement for older technology found on other satellites. Then again, in Aviation Week's previously cited article two informed sources say that it probably did not carry imaging radar. One reason is that it was launched on the less powerful Delta 2, suggesting too small a launch capacity; they say a heavy booster would have been needed to put a radar system into orbit. They also asserted that: "It's also thought not to be a product of NRO's traditional imagery, signals or communications intelligence shops. Instead, itâ€™s a smaller passive systemâ€”"not radar, optical or ladar"â€”that was cobbled together by the organizationâ€™s fast-development, advanced science and technology office, the aerospace official says. It also appears to be an offshoot of earlier NRO work on small, cheap, fast-reaction, imaging satellites. The U.S. is admittedly looking hard at how it could rapidly repopulate its intelligence-gathering satellite network if the current constellations are targeted by antisatellite weapons or network and electronic attack." Of course, all this "passive" technology may be of high value to the enemies (and friends) of the U.S. And, of course, all of this is impossible to verify. The DOD's News Briefing transcript here sticks mainly to the hydrazine explanation. So, maybe I'm being cynical about our government's intentions. But then, cynicism would also not be surprising, nor uncharacteristic for the administration if it is hiding under the "green" umbrella that so many corporations like to unfurl to protect them from the fallout of their more nefarious deeds. My gripe isn't with the Pentagon. I understand that they've got intelligence secrets to keep and classified arms races to run. And getting clobbered by a tank of hydrazine is nothing to make light of. But it is unfortunate that much of the mainstream media largely bought their cover story with nary a question. Even if most of those queries about spy satellites cannot (and some of them needn't) be answered, the media should ensure that corporations, governments and others find it's not that easy being green. -- Edited by Michael Battaglia at 02/21/2008 2:55 PM