Space Warfare - Practical Considerations

Practical Considerations

Space warfare is likely to be conducted at far greater distances and speeds than terrestrial combat. The vast distances involved pose difficult challenges for targeting and tracking, as even light requires a few seconds to traverse ranges measured in hundreds of thousands of kilometers. For example, if attempting to fire upon a target at the distance of the Moon from the Earth, the image one sees reflects the position of the target slightly more than a second earlier. A projectile from a railgun recently tested by the US Navy would take over eighteen hours to cross that distance (making the simplifying and optimistic assumption that it will travel in a straight line at a constant velocity of 5.8 km/s along its entire trajectory). Even a laser will need approximately 1.28 seconds, meaning a laser-based weapon system would need to lead a target's apparent position by 1.28×2 = 2.56 seconds.

Three factors conspire to make engaging targets in space very difficult. First, the vast distances involved mean that an error of even a fraction of a degree in the firing solution could result in a miss by thousands of kilometers. Second, space travel involves tremendous speeds by terrestrial standards—a geostationary satellite moves at a speed of 3.07 km/s whereas objects in low earth orbit can move at up to 8 km/s. Third, though distances are large, targets remain relatively small. The International Space Station, currently the largest artificial object in Earth orbit, measures slightly over 100m at its largest span. Other satellites can be orders of magnitude smaller, e.g. Quickbird measures a mere 3.04m. External ballistics for stationary terrestrial targets is enormously complicated—some of the earliest analog computers were used to calculate firing solutions for naval artillery, as the problems were already beyond manual solutions in any reasonable time—and the issues in targeting objects in space make a difficult problem even harder. Additionally, though not a problem for orbital kinetic weapons, any directed energy weapon would require large amounts of electricity. So far the most practical batteries are lithium batteries, and the most practical method of generating electricity in space is through photovoltaic modules, which are currently only 5-18% efficient, and fuel cells, which have limited fuel. Current technology might not be practical for powering effective lasers, particle beams, and railguns in space.

Regardless of one's reasons for going to war, at present those reasons are not likely to suggest major targets located in space. Most of the main theories which attempt to explain human proclivity for warfare—psychological, sociological, demographic, economic, political, or otherwise—would not indicate space as a likely location of conflict until a significant population is engaged in large-scale activity there. Until then, space warfare is likely to take a supporting role to conventional, terrestrial warfare.

Aside from applications such as communications, reconnaissance, GPS, and the like, which would be difficult or impossible without satellites, there do not appear to be any major advantages to basing weapons systems in space. The main reason is simply cost. Space warfare that involves humans being deployed in space to fight each other is not currently practical because of the difficulty and cost of sustaining human life in space, especially over long periods of time.

Additionally, there are few things that could be accomplished by space warfare that any nation wealthy enough to finance them cannot accomplish far more cheaply through conventional means. Raising any significant mass beyond Earth's gravity will always require a large amount of energy, and the cost increases with mass. For example, though kinetic bombardment potentially offers the ability to strike any target anywhere in the world within minutes, both the United States and Russia, possibly the only nations with the resources and facilities necessary to implement such a system, have sufficiently long-range supersonic bombers that the same target could already be deployed in a matter of hours at a mere fraction of the cost.

General William L. Shelton has said that in order to protect against attacks, Space Situational Awareness is much more important than additional hardening or armoring of satellites.