The White House Death Star petition was a joke, but the prospect of war in outer space is anything but.
"The wars of the future will not be fought on the battlefield or at sea," a military academy commandant voiced by Willem Dafoe intones toward the end of a now-classic 1997 episode of The Simpsons. "They will be fought in space, or possibly on top of a very tall mountain." This was meant as a joke, but the latter half of that statement would soon prove eerily prescient when India and Pakistan battled over Kashmir's Siachen glacier -- a strategically irrelevant ice field sitting over 18,000 feet above sea level -- during the Kargil War in 1999. For now, the prospect of military conflict in outer space still resides in the realm of dystopia or absurdity, to the point that a White House petition demanding the construction of a Star Wars-style "Death Star" could be treated as a harmless prank. In rejecting the petition this week, the White House rightly wondered why a debt-strapped U.S. government would spend $850 quadrillion on a weapons system "with a fundamental flaw that can be exploited by a one-man starship." Thankfully, the prospect of an orbital space-to-earth battlestation doesn't even need to be treated seriously.
But it wasn't always this way. In 1952, the eminent rocket scientist Werner Von Braun imagined that a future space station would function as an orbital nuclear platform. Space historians believe that Russia's Salyut 3 space station, which was launched in June of 1974, had a cannon on board, in case a craft or satellite from an enemy country attempted to disrupt its mission. The Soviet Union experimented with Fractional Orbital Bombardment Systems in the 1960s and 70s -- basically nuclear delivery systems that were capable of orbiting the earth. The U.S. even detonated a nuclear weapon over 200 miles above the Pacific Ocean in July of 1962, an incident known as Starfish Prime that, according to Harvard University astrophysicist Jonathan McDowell, halved the useful lifetime of all satellites then in orbit, knocked out power in Hawaii, created an artificial Van Allen Belt that persisted for five years, and released radiation into the atmosphere that wouldn't fully dissipate until the end of the decade. For a time, it was all but taken for granted that space would not only be militarized, but weaponized -- used as a venue or staging area for violent clashes between space-faring nations, or attacks on the surface of the earth. Space war wasn't a punch line, but a possibility that nuclear-armed powers didn't think they could afford to ignore.
The results of the Starfish event hint at one reason why that changed. "This is a great weapon. It does a lot of damage -- but it also killed everything you had yourself," McDowell says of the results of the high-altitude nuclear test. War in space was sure to have a cataclysmic effect on the country with the most space assets, regardless of the end result.
But what about war from space? For powerful space-faring countries, space-to-earth or earth-to-space combat is about as practical as it is desirable -- which is to say, not very. "Space is incredibly useful for the military for a lot of things," McDowell explains. "It's great for intelligence, communication and navigation. The natural thing is to ask, 'where are my X-Wing fighters?' The fact is that it's hard to find a rationale for them."
'This is a great weapon. It does a lot of damage -- but it also killed everything you had yourself.'
Laura Grego, a senior scientist in the global security program at the Union of Concerned Scientists, explained why an orbital weapons platform -- the kind of big-ticket military asset that you might want a fleet of X-Wing-type vehicles to protect -- is impractical for attacking targets on earth. "Everything in space is moving at rapid speeds. At the same time, the earth is rotating underneath it....as it's going around, you can't hold [the weapon] above your target. You might be over one country for 15 minutes and then you're gone." This tiny orbital window is called the absentee ratio, and an ICBM, which can hit any target on earth within minutes, isn't constrained by one. McDowell added that in order to reach atmospheric velocity, a rocket needs to reach a breakneck seven kilometers-per-second, far faster than the four to five kilometers-per-second an ICBM must travel. From a purely strategic standpoint, orbiting a weapon for space-to-ground use is more expensive and far less useful than existing, more earth-bound capabilities.
Simply orbiting a nuke, while possible, is good for little other than blackmail, or, at best, a Dr. Strangelove or Dead Hand-style insurance policy for a paranoid and heavily-armed space-faring state. The space nuke would be a means of ensuring that someone (or some thing) has the capability of effectively wiping out most or perhaps all of the 1,016 satellites that currently orbit the earth, while rendering their orbits so debris-strewn as to be totally and perhaps permanently useless. Such dangerous and cavalier behavior is the stuff of cinematic super-villainy -- not statecraft.
But there's another, more idealistic reason humanity is safe from the scourge of space war. And ironically, it suggests that we might not be safe forever.
The ban on Death Star-like orbital weaponry is one of the more robust norms in international law. A prohibition on stationing weapons of mass destruction in space, as well as the total demilitarization of the Moon, is enshrined in article 4 of the Outer Space Treaty of 1967, which 126 countries have signed. As University of Nebraska law professor and space law expert Frans von der Dunk notes, the treaty bans the stationing of weapons of mass destruction in space without banning their actual use in space. The stationing and use of kinetic or conventional weaponry is also allowed. Yet the most worrying aspect of the current legal regime is that the laws of war extend to the heavens as well. "The general international law on the law of force and the prohibition on the use of military force also applies in outer space," says von der Dunk. "If, as part of your self-defense you need your satellite to shoot down the satellite of your aggressor...that is perfectly allowed."