The Case for Space in Ballistic Missile Defense

March 7, 2005

If future ballistic missile defense uses space, it will be with good reason.

For a start, ballistic missiles fly through space. The further a ballistic missile must travel, the higher it must fly, and in order to reach a target more than 100 miles away, a ballistic missile must fly to such an altitude that it passes into space.

In the initial or "boost" phase, a ballistic missile must struggle against gravity and the earth's atmosphere, it is burdened by the weight of its fuel, and it trails a long, hot flame behind it, all of which makes the missile slower and more obvious. In boost phase, a ballistic missile is still in one piece; After that, the missile releases its warheads and decoys, greatly mulitiplying the number of targets for any missile defense system. Once the warheads begin their descents, gravity accelerates them by 10 meters per second, every second, and they can reach phenomenally high speeds which again magnify the difficulty of intercepting them. Missile exhaust, which can be detected by heat and light sensors, does not trail descending warheads as it does rockets in boost phase. And debris from a ballistic missile destroyed in boost phase would fall back onto the aggressor's territory, as opposed to a targeted or neutral nation's.

So a ballistic missile is most vulnerable and harmless during the boost phase. But that lasts five minutes at most. If an interceptor must travel half way around the world to catch up to a ballistic missile, then by the time it does, boost phase will be long over. Stationary and mobile BMD radar and interceptors can be distributed widely over land and sea, and aircraft fitted with BMD sensors and lasers can patrol the skies so that, wherever a ballistic missile might be launched, the wherewithal to detect and destroy it would be reasonably nearby. But it is difficult, logistically and diplomatically, to achieve with those systems the sort of coverage necessary to defeat ballistic missile threats during boost phase.

To better ensure that, defense scientists look to space. The most advanced space-based BMD system being proposed is Space-Based Laser, or SBL. A network of 12 to 20 satellites, each equipped with sensors and armed with a laser, would continually orbit the globe on different courses so that at any given moment, at least one satellite would be within range of any possible ballistic missile launch, anywhere on earth. Each satellite would have the ability to both detect and destroy, and would sense a ballistic missile, compute the missile's track, and correct its own laser fire, all so immediately that the missile would be shattered shortly after emerging above any cloud cover. To defeat ballistic missiles during the criticial boost phase, a space-based system would be the closest to failsafe.

Although the use of space for ballistic missile defense has been proposed for at least two decades, space-based systems are still only proposals; The current U.S. BMD system, with which Canada was asked to cooperate, is not space-based.

We have opposed a rudimentary earth-based missile defense system intended to protect against accidental or limited ballistic missile attacks in this age of terrorism, largely out of ostensible concern that it could proceed to space-based missile defenses, and that they could proceed to space weaponry which would give America an unprecedented and unrivalled military capability. But what does America have today if not precisely an unprecedented and unrivalled military capability, and under that aegis the world is moving toward greater and greater freedom. America has today the ability to strike at will, anywhere on earth, and enough firepower to destroy the world 200 times over; Any possible future space weaponry could only update America's existing doomsday arsenal.

Space has of course already been militarized in that satellites orbiting earth today provide military surveillance and targeting for bombing. But space has also already been weaponized in that ballistic missiles use space to enable faster, farther flight, and nuclear warheads in an EMP attack would use the first couple hundred miles of space to generate an electromagnetic pulse to damage or destroy electronics and electrical grids on earth below.

We ought not assume that a ballistic missile attack against America would be America's problem and none of our concern. Even if the effects of an attack could be expected to stop south of the U.S.-Canadian border, our trading partnership is such that Canada would suffer an economic upheaval if an American city were devastated or if America were electronically incapacitated in a ballistic missile strike and the U.S. economy collapsed in its wake. In what is becoming a trend, our natural and historic allies in the English-speaking world -- America, Britain, and Australia, plus Denmark and Japan -- are confronting yet another threat while we wring our hands, though we were not asked even to shoulder a share of the burden. Canada was perfectly entitled as a sovereign state to decide against joining America's missile shield, but it is equally entitled to change its mind.

Andrew W. Smith, Cape Sable Island, Nova Scotia and Tulsa, Oklahoma

Published in The Halifax Chronicle-Herald