Two lonely satellites drift through the vastness of space, alien to wonder at their starry surroundings, imaginations bound by relentless orbital monotony and dreary earthly demands when - doink! - they glance off each other like blobs in a lava lamp. We're not alone!" they chatter in excited electronese, awakened. "Cosmic, man."
Reality check: bummer, dude. Contrary to the impression left in many minds by years of media clips featuring astronauts gaily bobbling floating milk globs, satellites don't drift, they haul ass - the average closing speed between objects in orbit is 22,000 miles per hour.
At that speed, a collision is no gravity-free moment, it's a metal-vaporizing cataclysm. And with more than 8,500 objects - satellites and satellite-spawned debris (read: junkyard) - the size of a softball or bigger whizzing around the world, it's a chance encounter whose chances have grown increasingly large. They're not alone, all right.
"Since the 1950s, people have been launching things with a total disregard for space debris issues," says prominent satellite insurance broker Alden Richards, "I think there are going to be collisions - what we don't know is how many and when."
Actually, it's already happened. Just last year, a French satellite lost its electronic life in a warp-speed wipeout with a suitcase-sized chunk of typical space junk: a discarded rocket stage, the remnant of 40 feverish years of post-Sputnik space-racing that's littered near-earth space with roughly 1,300 rocket bodies, some 6,700 springs, bolts, explosion fragments, and dead satellites; and a random assortment of screwdrivers and other miscellaneous jetsam. Not to mention the 600-plus active satellites.
Just weeks ago, a US military satellite missed drilling the hapless Mir space station (mercy killing?) by less than 500 yards.
Space just isn't so ... spacious anymore.
Distribution of Objects in Orbit
__Source:__Interagency Report on Orbital Debris 1995
Enter Teledesic ... and Iridium, and Globalstar, and Celestri, and SkyBridge, and on and on. In all, almost a thousand new satellites are scheduled for launch in the next 10 years - most of them into low-earth orbit, where the debris swarm is the most dense. Are we in danger of over-seating the celestial arena? Some say we already have.
In 1990, a pair of German scientists at the Technical University of Braunschweig, Peter Eichler and Dietrich Rex, released a study claiming that space debris had already reached a deadly critical mass - that it would only be a matter of time before a catastrophic collision created an enormous, spreading debris cloud that in turn spawned further collisions, and so on, until certain orbital altitudes became an impassable buzz-saw of shrieking metal. It's a theory called the Cascade, and it scares the bejesus out of a lot people. "In an extreme, apocalyptic case," says Steven Aftergood from the Federation of American Scientists, "it could cause a kind of planetary quarantine, in which much of Earth's orbit would be rendered totally unusable, and if we don't take steps to mitigate it, the extreme could come to pass."
But Nick Johnson, head of NASA's Orbital Debris Research Project and the world's arch-guru of debris analysis, downplays the threat of a catastrophic chain reaction: "We do not ascribe to that particular assessment. We believe it's a long-term potential, one that is not inevitable, and is not near term." Johnson's not critical of Eichler and Rex - Eichler now works for him - but of their outdated debris-field prediction models, circa 1990. "The discipline has matured greatly since then - they had a very low-fidelity model, and they got a very low-quality result."
Still, the 1990 assessment was based on 1990 debris levels, before Teledesic and the gang burst on the scene with their bustling LEO constellations; in 1997, there's a lot of new heavenly metal to factor into critical-mass equations. Or maybe not: Johnson's not convinced that a sudden increase in orbital mass is forthcoming. "I think hope springs eternal in the human breast - no way in the world do I believe all those satellites are going to go up," he says.
Even if they do, Johnson says, they won't contribute significantly to the debris problem. NASA has actively educated the industry to the threat of space junk, and it's banking on the strength of economic self-interest - companies don't want mega-million-dollar satellites flying through their own trash - to serve as a potent self-policing force. Indeed, many companies such as Teledesic intend to take aggressive action to minimize future debris-generation - rocket stages will deorbit, lens caps and other potential jetsam will be tethered to the satellites, and the satellites themselves will deorbit at mission's end, burning up harmlessly in the atmosphere. "What’s the net effect on the environment? Essentially zero," Johnson says. "Now, will everybody do that? I don’t know."
Aye, there's the rub.
"Everyone says that everyone's working in everybody's interest, but it'd be a lot better if there were an international decree," says Alden Richards, CEO of Space Machine Advisors, a satellite insurance brokerage. "I don't think there is self-policing."
Richards and others in the bottom-line based, risk-minded realm of satellite insurance fear that in the scramble for a chunk of the trillion-dollar telecom market companies may let short-term interest outweigh long-term space citizenship, trimming costs by eliminating expensive deorbit and debris minimization measures. These insurers see international regulation as the only remedy.
NASA's Johnson acknowledges that certain companies might not play by the rules, but he doesn't want to see competition quashed by heavy-handed environmental regulation spawned in the bowels of UN bureaucracy. "We're trying to be as unobtrusive as possible. We prefer to give the industry the chance to regulate itself."
Other scientists agree: "Debris has been an issue of debate at COPUOS, the UN Committee on Peaceful Uses of Outer Space, but that committee never accomplishes anything useful," says scientist Aftergood, "It's a hideous way to try to determine international space policy."
Even if the UN were to issue any sort of ruling, it wouldn't be soon. The COPUOS scientific and technical team is in the midst of a three-year review of the space debris issue. "Our position is that we don't have a problem yet, so we’re not looking for a solution," says Johnson, the US delegate to COPUOS.
They may not have a problem yet, but they just might, come 17 November 1998.
Man may have stirred up a little dust cloud of near-earth debris, but leave it to Mother Nature to whip up a real cosmic shit-storm. Every 33 years, or so, she unleashes the Leonids, a torrent of meteoroids that tears through Earth's orbital field at more than 160,000 mph on the tail of the comet Tempel-Tuttle. On a normal night, you might see half a dozen meteors; in the next Leonids storm on 17 November 1998, you'll see 150,000 or more. "It’s the closest thing there is to an interplanetary dust hurricane," says Peter Brown, the world’s preeminent Leonids specialist at the University of Western Ontario.
And just how do satellites handle hurricanes? "That's the million-dollar question," says Brown, "No one who works on satellites has factored in meteor storms."
Perhaps they should: Brown predicts that five to 10 satellites will be hit by Leonids meteoroids in the next storm. The problem is compounded by the Leonids' extreme speed. When objects collide at 160,000 mph they don't fragment, they liquefy, surrendering ions from their molecular structure and creating an electrically charged plasma cloud. At hypervelocity, even a collision with a tiny meteor can produce a charged plasma cloud that permanently disrupts a satellite's electronic system, effectively destroying it.
Such a collision has already claimed a victim, during a comparatively tame Perseid meteor shower. In 1993, a Perseid hit the European space satellite Olympus at hypervelocity, inducing a slew of electrical problems that ultimately rendered it useless.
NASA's Johnson admits that the space industry doesn't quite know what to expect from the Leonids: "This is a situation we've never knowingly experienced before," he says. But he downplays the threat: "Our gut feeling is that it's not going to be that much of a problem.... It looks like during a 12-hour period on November 17, your spacecraft might experience [meteoroid] exposures that are equivalent to a few months in space."
Nevertheless, he says, the space shuttle will not fly during the meteor storm, and satellites - government and industry alike - will be re-positioned to minimize their cross section relative to the incoming meteoroids.
But beyond that, Johnson says, bowing before the power of nature like a San Franciscan at the San Andreas fault, "There's not a whole lot you can do about it."
