12 June 2018xe2x80x94The world awakens to an international crisis: officials at the Tokyo airport have detained a foreign airliner suspected of carrying illegal arms. The aggressive and threatening response from the planexe2x80x99s country of origin, a xe2x80x9croguexe2x80x9d state believed to possess both nuclear and biological weapons, adds credibility to the suspicion. Hamstrung by its rogue status, the countryxe2x80x99s economy has been in free fall for decades, and with this latest incident, itxe2x80x99s widely feared that the country will launch a nuclear attack against Japan. U.S. satellites report escalating activity at the countryxe2x80x99s rocket-launch facility; other U.S. intelligence indicates that three intermediate-range missiles are being fueled and are within a 15-minute launch window. No air-, sea-, or land-based military system is available to respond in time. The U.S. president demands that the country cease and desist immediately but receives no response. Five minutes later, the U.S. Strategic Command activates a heretofore undisclosed space-based laser; within minutes, it incinerates the launch facilityxe2x80x99s command and control center, thus narrowly averting a catastrophe.

Today, such a scenario is science fiction, but itxe2x80x94or something like itxe2x80x94could become reality within the next decade or two. The irony is that the economic and political price the United States would have to pay to bring about such a system, even if it could be done, might well outweigh its military benefit.

No country today is known to have weapons deployed in space, and many countries oppose their development. However, at least some U.S. Pentagon officials have been arguing that the United States must now, after decades of debate, develop and deploy offensive space weapons. In fact, over the past 10 years, the U.S. government has spent billions of dollars researching and testing such weapons. If deployment became official U.S. policy, such a step would have profoundxe2x80x94and, we feel, profoundly negativexe2x80x94implications for the balance of global power.

The United States itself, our analysis suggests, would discover that the military advantages that might be gained from space-based weapons are outweighed by their political and economic costs. Deploying such weapons would also create new, asymmetric vulnerabilities to U.S. armed forces, as we will describe in this article. In addition, it would be a significant political and strategic departure from 50 years of international law and diplomatic relations.

The U.S. and North Atlantic Treaty Organization (NATO) militaries already make extensive use of space-based systems. Satellites revolutionized conflicts such as Operation Iraqi Freedom, letting U.S. aircraft fly one-third the number of sorties and use one-tenth the number of munitions that they had expended just 10 years earlier in the Persian Gulf War. That economy was largely due to the great increase in accuracy offered by space systems.

Satellites are now routinely used to detect, identify, locate, and track targets. They also provide mobile, secure communication links between military control centers and theaters of operation; near-real-time imaging; signals intelligence; and meteorological data. And, of course, the constellation of Global Positioning System (GPS) satellites ensures that military personnel need never be lost amid a warxe2x80x99s chaos.

With capability, however, has come reliance. In the words of one U.S. Air Force space official, space systems are now xe2x80x9cwoven inextricablyxe2x80x9d throughout the military capabilities of the United States and its allies. Moreover, dependency on space is increasing. By 2010, the U.S. military expects, it will need twice the capacity of its existing space-based infrastructurexe2x80x94in everything from the number of images per day acquired from spy satellites to the bandwidth carried by communications satellites.

Without a doubt, the exploitation of space has helped the U.S. military remain the most technologically advanced fighting force in the world. At the same time, though, it has made that force deeply vulnerable to an attack on its satellites and other space-based systems. Whatxe2x80x99s more, the means to disable or disrupt this valuable and complex machinery are well within the reach of even technologically unsophisticated adversaries.

Indeed, with some U.S. military planners advocating the development of what would be the first-ever space-based systems for offensive operationsxe2x80x94what the military refers to as force projectionxe2x80x94the country finds itself fast approaching a crossroads. Space, these planners assert, will usher in a revolution in global warfare, with U.S. space-based weapons delivering destructive force to any point on the globe within minutes, and without the risk or cost of sending troops.

Realizing the growing strategic value of space, in January 2001 a congressionally mandated space commission headed by incoming Secretary of Defense Donald H. Rumsfeld urged the United States to maintain the option of weaponizing space, identifying three potential missions for space weapons:

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• Protecting existing U.S. systems in space.

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• Denying the use of space and space assets to adversaries.

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• Attacking from space a target anywhere on land, at sea, or in the air.

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In the four years since the Rumsfeld commission released its conclusions, the report has continued to guide U.S. policymaking in this arena. For instance, the U.S. Air Force last year outlined a series of potential space weapons initiatives as part of its 176-page Transformation Flight Plan [PDF]. Among the weapons described were space- and ground-based lasers, antisatellite missiles, and a futuristic constellation of orbiting high-power radio frequency transmitters capable of disrupting or disabling electronics. A press statement that accompanied the reportxe2x80x99s release in February 2004 described it as xe2x80x9ca road map to the future.xe2x80x9d

The idea of putting weapons in space is not new. Beginning in the 1960s, at a time when satellites were still quite rare, the former Soviet Union and the United States both tested antisatellite weapons. Despite several decades of development, however, neither country managed to deploy any such weapons. Then, during the Reagan administration, supporters of the Strategic Defense Initiative advanced proposals ranging from space-based lasers to xe2x80x9cBrilliant Pebbles,xe2x80x9d numerous small orbiting projectiles to be fired at ballistic missiles in hopes of destroying them [see sidebar, xe2x80x9cMissile Defense from Spacexe2x80x9d].

Considerable research netted no system worth deploying. Though such systems were positioned as defensive in nature, the line between offensive and defensive space weaponry is more philosophical than technological: the same laser that could be trained on a rogue missile could easily target a commercial satellite instead. Likewise, the technological problems that plagued defensive space weapons will also apply to new offensive designs.

Critics of space weapons have long insisted that developing and deploying space weapon systemsxe2x80x94if feasible at allxe2x80x94would be prohibitively expensive and technologically difficult. The majority of the international space-faring community calls instead for a perpetuation of the status quo: the use of space to support terrestrial military activities through communications, reconnaissance, navigation, and even weapon guidance, but not for direct application of force. In other words, the militarization of space is acceptable; the weaponization is not.

Now, as the U.S. national security community nears a decision point, policymakers are split on several fundamental questions:

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• Can space weapons effectively mitigate the existing vulnerabilities of U.S. and other satellites and space systems?

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• Will space weapons be better than terrestrial alternatives at projecting force and denying adversaries the use of space?

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• Will expected gains from space weapons outweigh financial, strategic, and political costs?

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• Assuming for the moment that space weapons would further U.S. interests, but taking into account that several other countries also have the ability to deploy them, should the United States be the first to do so?

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What is axc2xa0space weapon? As commonly defined, it is a system designed to project destructive force between Earth and outer space or within space itself. Antisatellite weapons, space-based lasers, space-based platforms that fire projectiles, and ground-based lasers that rely on orbiting mirrors to reflect beams to space or back down to Earthxe2x80x94all fit the definition. On the other hand, intercontinental ballistic missiles, ground-based electromagnetic jammers aimed at satellite signals, and explosives used to attack satellite ground stations are not considered space weapons.

nnSpace Arrows:xc2xa0Rods of tungsten, stored on an orbiting platform (top), would be released to strike buried targets on Earth. However, each rod would take several minutes to reach its target and would be difficult to steer, limiting the weapon to attacking fixed positions. There is also an upper bound on the rodsxe2x80x99 velocity, which means their destructive force would be similar to that of cheaper conventional explosives.nIllustration: John MacNeilln

For the most part, space weapons can be classified into four categories: directed-energy weapons, kinetic-energy weapons, conventional warheads delivered to or from space, and microsatellites.

A directed-energy weapon uses a beam of electromagnetic energyxe2x80x94whether laser light or high-powered radio wavesxe2x80x94to destroy a target. In the case of a laser, the beam heats a target until it melts or catches fire. A radio-wave weapon stimulates the targetxe2x80x99s electronic circuits until they are inoperable [see xe2x80x9cThe Dawn of the E-Bomb,xe2x80x9dxc2xa0IEEE Spectrum, November 2003].

The most widely discussed directed-energy weapon is the space-based laser (SBL), an orbiting system that would use powerful lasers with large mirrors to focus energy on a selected target on Earth, producing damaging or destructive levels of heat. Over the past decade, the Pentagon has spent roughly US $750 million on SBL research, funded primarily by the Air Force and the Ballistic Missile Defense Organization (now the Missile Defense Agency).

Various components have been tested on the ground and in the lab, including a megawatt-class chemical laser and the apparatus for pointing and controlling the beam, but the full system has yet to be tested in orbit. Although the U.S. Congress suspended funding in 2003 and called for a review of the program, the concept remains very much alive.

Directed-energy weapons propagate their energy at the speed of light, so their effects begin with no appreciable delay beyond the time necessary to acquire a target and point the laser. However, to have the desired result, the beam must remain on target for some time. For example, to attack a ballistic missile at a range of 3000 km, a space-based 3-MW laser with a 3-meter-diameter mirror stationed 1000 kilometers above Earthxe2x80x99s surface, in low Earth orbit (LEO), requires an impractical 2 hours and 13 minutes to burn through the rocket casing ; a 30-MW laser with a 10-meter-diameter mirror in the same orbit and at the same range would take a more reasonable 80 seconds [see illustration, xe2x80x9cLight Saberxe2x80x9d]. For comparison, the entire flight of an intercontinental ballistic missile, from launch to impact, would last only about 45 minutes.

xe2x80x9cBurnxe2x80x9d time aside, directed-energy weaponsxe2x80x99 speed-of-light propagation cannot be matched by any other weapon. This feature suits them well for time-critical targets or those in remote locations or beyond the reach of conventional forces, such as the launch site described in the opening scenario. But even if the targetxe2x80x99s location is known precisely, the laser is useless if clouds or smoke intervene.

Kinetic-energy weapons destroy targets by smashing into them at high speed (they are not explosive). According to basic Newtonian physics, the impact energy increases linearly with the projectilexe2x80x99s mass but as the square of its impact velocity. Because collision speed is comparable to orbital or missile speed, an inert projectile would be sufficiently destructivexe2x80x94assuming it finds its target. Such velocities would also help the projectile elude countermeasures and defenses, penetrate armor, and reach buried targets.

Hypervelocity Rod Bundles are a leading candidate. More colloquially known as Rods From God, they are long, slim, dense metal rods, typically of tungsten or uranium, each weighing perhaps 100 kilograms and deployed from an orbiting platform. Once a rod is released by the platform, a large two-stage rocket would bring it to a stop, after which orbital dynamics determine the projectilexe2x80x99s trajectory to a terrestrial target [see illustration, xe2x80x9cSpace Arrowsxe2x80x9d]. The slender rods would eventually reach a speed of several kilometers per second if dropped from LEO, their length facilitating the penetration of hard or buried targets.

Because the rodsxe2x80x99 trajectory paths from LEO would be many hundreds of kilometers long, they would require about 5 minutes to reach their targets, so it would be difficult to use them against moving objects. Since no target is likely to be directly under the platformxe2x80x99s orbital path, each rod would have to be equipped with a rocket or some other means to move it from that path. Also, the rods would need shielding to keep them from burning up during reentry. The shielding and rocket both add weight and thus increase the cost of putting these weapons into orbit in the first place. Once the rod has reentered Earthxe2x80x99s atmosphere, it could be maneuvered by shifting an internal mass or by ejecting gas.

How destructive could such a weapon be? A 100-kg rod of tungsten falling from an altitude of 460 km and reaching an impact velocity of roughly 3 km/s would have the destructive force of a similar amount of conventional high explosives delivered by bomb or missile. The rod would be more effective than conventional high explosives at penetrating to a buried target, because the rodxe2x80x99s force would be concentrated and directed in the line of motion. Higher orbits would deliver greater energies but would take even longer to strike a targetxe2x80x94about 6 hours, for instance, from geosynchronous orbit.

Conventional warheads delivered from space are yet another candidate for the space weapons arsenal. (A conventional intercontinental ballistic missile, or ICBM, which also delivers bombs from above, spends relatively little time in space during its trajectory and is not a space weapon.) One proposal for delivering large quantities of conventional explosives is the Common Aero Vehicle (CAV), a robotic hypersonic aircraft much like a miniature space shuttle. Championed by the U.S. Air Force and the Defense Advanced Research Projects Agency, the Pentagonxe2x80x99s entrepreneurial R and D wing, based in Arlington, Va., the CAV would be launched into orbit by a land-based missile, aircraft, or some as-yet-undeveloped military space plane [see illustration, xe2x80x9cOrbital Bomberxe2x80x9d].

nOrbital Bomber:xc2xa0A robotic hypersonic aircraft could carry large amounts of conventional explosives to terrestrial targets. However, basing such a system in space would be prohibitively expensive.nIllustration: John MacNeilln

To attack, a CAV would come down from orbit, reenter Earthxe2x80x99s atmosphere, and maneuver to its target at speeds as high as Mach 25. Like the ICBM, the CAV would have one political edge over conventional aircraft: because the vehicle would reenter sovereign airspace only over the target country, the attacker would need no permission to fly over other countries.

CAVs could strike hard and deeply buried targets, naval bases, surface combatants, massed forces, mobile targets, air bases, and military and civilian infrastructure, to name a few examples. To strike a target on the other side of the globe would take about 45 minutes. Other advantages of such rapid strikes include having global reach, the ability to bypass enemy air defenses, and the absence of risk to pilots or support staff. However, in comparison with existing airborne alternatives and missile payloads, the CAV would be costly, and development would take many years.

Microsatellites, of all the space weaponry now being developed, are the closest to operational use. Microsatellite xe2x80x9cminesxe2x80x9d that would blow up or collide with other satellites could be ready to deploy within a few years of a decision to do so. If that decision has already been made, deployment could occur within days of a triggering event.

These small, maneuverable satellites would be launched into space on rockets or from larger satellites. Once in orbit, they would be self-powered and -guided. Microsatellites are being developed today for surveillance, inspection, and other nonoffensive tasks, but they could also be used as weaponsxe2x80x94for example, to attack a far larger and more valuable satellite by blowing up or simply colliding with it at high speed. With compact communications, guidance, control, sensing, and propulsion systems, a microsatellite might weigh only tens or at most hundreds of kilograms, compared with its full-sized cousins weighing thousands of kilograms or more [see illustration, xe2x80x9cMobile Minexe2x80x9d].

nMobile Mine:xc2xa0Cheap and maneuverable, a microsatellite could creep up on an enemy satellite and either explode or simply collide with it. But if the United States deployed such weapons, it could open the floodgates to similar threats to U.S. military and commercial satellites.nIllustration: John MacNeilln

Drawing a line between peaceful and hostile microsatellites may be impossible. In January 2003, the U.S. Air Force demonstrated its XSS-10 microsatellite, which repeatedly maneuvered to within 35 meters of a target to take photographs. Had it been equipped with a gun instead of a camera, it could have destroyed the target.

Within a few months, the Air Force is due to launch the follow-up XSS-11, designed for xe2x80x9crendezvous and proximity operationsxe2x80x9dxe2x80x94that is, meeting with other satellites to perform inspections, maintenance, and the like. However, as an unnamed U.S. defense official candidly acknowledged in an interview with Inside the Pentagon in December 2003, the XSS-11 could also be used as an antisatellite weapon.

The United States is not unique in its microsatellite capability. Over the last decade, for instance, researchers at the University of Surrey, in Guildford, England, have successfully launched a range of nonmilitary microsatellites, often in partnership with teams from other countries, and have orbited and tested a xe2x80x9cnanosatellitexe2x80x9d weighing less than 10 kg.

In a sense, microsatellites are as old as space exploration itself. Sputnik-I, weighing in at 84 kg, was technically a microsat, and many of the spacecraft that followed in those early years were similarly small. In the five decades since then, researchers worldwide have steadily refined microsat components, helped tremendously by the general shrinking of sensors and circuitry for computers and communications. At present, a microsatxe2x80x99s guidance and control systems can be miniaturized to considerably less than 1xc2xa0kg, and can derive both propulsion and power from solar cells, thus reducing weight and launch costs.

Although microsatellites are perceived primarily as a threat to satellites in LEO, they could be adapted to attack assets in geosynchronous orbit as well. A space mine would be effective only if it were orbiting very close to its quarry, in an almost identical orbit. The space mine would not need to be deployed covertly; there would be no means of destroying or disabling the mine without also risking the destruction of its much more valuable target, so the mine poses a similar threat whether its presence is known or unknown.

Should the United States, or any nation for that matter, weaponize space? The answer depends not simply on the capabilities and limitations of proposed space weapons but also on the military objectives. The Rumsfeld commission laid out three objectives in which space weapons might play a role: to defend existing military capabilities in space; to deny adversaries the military benefit of space; and to attack adversaries from or within space.

The last objective is perhaps the most alluring: the prompt and deadly projection of force anywhere on the globe. The psychological impact of such a blow might rival that of such devastating attacks as Hiroshima. But just as the unleashing of nuclear weapons had unforeseen consequences, so, too, would the weaponization of space. Whatxe2x80x99s more, each of the leading proposed space weapons systems has significant physical limitations that make alternatives more effective and affordable by comparison.

Except for those in geosynchronous orbit, all satellites are in motion relative to Earth. Space weapons would be no different. A satellite in LEO, for example, circumnavigates the globe roughly every 90 minutes. Traveling at high speed relative to the ground, each satellite has a limited window during which to strike a particular ground locationxe2x80x94from LEO, typically 1 or 2 minutes, during which time the satellite moves 500 to 1000 km.

A reasonable response time, then, means having an overlapping constellation of many satellites. A satellite capable of destroying a target up to 3000 km away could cover a circular area of 28 million square kilometers, or about one-18th of Earthxe2x80x99s total area. In theory, 18 identical laser-weapon satellites would be needed to cover every location on Earth. Unfortunately, the circular coverage areas of the individual satellites would provide overkill at some points and no effectiveness at others. For example, in a 2002 Air Force-sponsored RAND report, xe2x80x9cSpace Weapons, Earth Warsxe2x80x9d [PDF],xc2xa0Bob Preston and his coauthors describe how a constellation of twenty-four 5-MW hydrogen-fluorine lasers with 10-meter-diameter mirrors would usually be able to destroy two to four ballistic missiles launched simultaneously from a small area, but if one missile was launched every 5 minutes or so, the constellation would be able to destroy just one.

For lower-power lasers, the number of satellites escalates. For 1-MW beam power, 120 satellites could kill a launch of four missiles most of the time, but occasionally would be able to destroy only three. The main point is that many weapons (of any type) need to be orbiting to ensure that at least one weapon is within range to strike any possible target at any given time.

An additional challenge for space-based lasers is their vulnerability to countermeasures. As we have noted, even the highest-power lasers do not penetrate clouds or smoke, and some wavelengths cannot penetrate Earthxe2x80x99s atmosphere, including those used by the HF laser currently proposed for space-based missile defense. For ground targets, smoke pots could disrupt an attack already in progress.

Vulnerability is increased by the need to keep the laser on target for tens of seconds at least. The target could move in an unpredictable path or simply be covered with a reflective coating or paint, which could increase the time required for a successful kill by a factor of 10 or more. A layer of titanium oxide powder, for instance, could reflect 99.9 percent of the incident laser energy. Even a shallow pool of dyed water would offer serious protection for structures. Since a 20-MW laser boils water at a rate of 10 kg/s, a pool of water about 3 centimeters deep on the flat roof of a two-car garage would protect against 100 seconds of illumination by a space-based laser. This all adds up to abundant opportunity to thwart laser weapons.

Meanwhile, the laser would be burning its supply of hydrogen and fluorine at a rate of 500 kg/s. Over the course of 100 seconds, it would consume 50 tons of fuel, for which the launch costs alone are about half a billion dollars.

The issue of energy requirements warrants a closer look. Today, the most efficient high-power lasers typically consume 2 to 3 kg of chemical fuel per megawattsecond. So a pulse of 20 seconds from a 10-MW laser corresponds to about 400 to 600 kg of fuel per target in the absence of any countermeasures. At current launch costs of some $22 000/kg into low Earth orbit, each 20-second laser shot would cost approximately $11 million. For a constellation of 17 lasers, each loaded with a 12-shot capacity, the launch cost to maintain on-orbit fuel alone would exceed $2 billion. Weigh that against a stock of highly effective $6 smoke grenades, a stray cloud, or a 3-cm-deep pool of water, and this multibillion-dollar weapon system starts to look like a poor investment.

If lasers are prohibitively expensive, might long tungsten rods used as high-speed penetrators be a relative bargain? Not really. To guarantee that a single target (located near the equator, to take the easiest case) could be attacked at will, and not only when a single orbiting rod happened to pass overhead, a distributed constellation of some 40 rods would be necessary, with launch costs totaling some $8 billion.

The additional problems of targeting at supersonic speeds and coping with the intense heat of reentry demand extremely advanced, and therefore costly, technologies. Although one can steer the rod by shifting its center of mass, one would still need to obtain error signals to guide the penetrator to the target. Communicating with the penetrator is complicated by the fact that the surrounding air is heated into a radiopaque plasma, obstructing even the reception of GPS navigation signals. Although none of these problems is insoluble, they defy inexpensive solutions.

For attacking hardened or deeply buried targets, the long rods would not outperform existing missiles equipped with conventional penetrating warheads. Thatxe2x80x99s because the physics of high-velocity impacts limits the penetration depth; basically, too much energy at impact causes the projectile to distribute its energy laterally rather than vertically. Tests done since the 1960s by Sandia National Laboratories, in Albuquerque, N.M., confirm that for even the hardest rod materials, maximum penetration is achieved at a velocity of about 1 to 1.5xc2xa0km/s.

Above that speed, the rod tip liquefies, and penetration depth becomes essentially independent of impact speed. Therefore, for maximum penetration, the long rods would need to be slowed to about 1 km/s, thereby delivering only one-ninth the destructive energy per gram of a conventional explosivexe2x80x94or about 1.5 percent of the potential energy the rod had in LEO. The wasted energy would be immense, and the effort, cost, and complexity of such an orbital system would be entirely out of proportion to the results.

For soft targets on the surface, such as aircraft, ships, or even tanks, the United States already has many quicker, simpler alternatives to space-based kinetic energy systems such as long rods. Explosives delivered by long-range cruise missile, ICBM, or submarine-launched ballistic missile are all more attractive options.

The space-based common aero vehicle also comes out a loser in comparison with weapons delivered by ICBM or shorter-range missile. Although the CAV may take only 45 minutes from launch to detonation, that would be preceded by as much as 12 hours for the target to come into range. Recall that an ICBM can get almost anywhere on Earth in 45 minutes. Of course, populating many orbits with CAVs would reduce the response time, but that would also run up the cost. Aircraft carriers, submarines, and even CAVs launched on demand by Earth-based missiles would all provide better performance than a space-based CAV.

Another objective laid out by the Rumsfeld commission was to defend existing military capabilities in space. While everyone agrees on the desirability of this goal, opinions vary over whether and how space weapons might help.

In framing the debate, it helps to consider the kinds of threats that existing satellites face. In roughly decreasing likelihood, these threats include: denial and deception (where an adversary conceals or camouflages its activities, hiding a chemical weapons lab within a mundane-looking agricultural fertilizer plant, for example, or using an underground bunker); electronic warfare (such as the jamming of satellite signals); physical attacks on satellite ground stations; blinding of satellite sensors with lasers; attacks in space by microsatellites; hit-to-kill antisatellite weapons; and high-altitude nuclear detonation.

Each threat would affect satellites differently. For instance, denial and deception thwarts only satellites performing intelligence-gathering missions. Satellites in geosynchronous orbit are less vulnerable to hit-to-kill weapons or a high-altitude nuclear burst. Other threats, such as electronic warfare and attacks on ground stations, could degrade the performance of all kinds of satellites.

Nor would space weapons be equally effective against these threats. Denial and deception, electronic warfare, attacks on ground stations, and satellite blindingxe2x80x94the four most likely threatsxe2x80x94would be mounted predominantly from the ground, and space weapons would offer little or no defense against them. Moreover, these threats are low-tech and inexpensive compared with space weapons.

Space weapons might prove useful against microsatellites, antisatellite weapons, and nuclear explosionsxe2x80x94attacks occurring in space and therefore more difficult to fend off from the ground. For example, a nuclear warhead detonated in space, even a warhead with one-100th the power of the 1.4-megaton hydrogen bomb that the United States tested at an altitude of 400 km in July 1962, would destroy or disable many of the hundreds of satellites in LEO [see illustration, xe2x80x9cEasy Preyxe2x80x9d].

nEasy Prey:xc2xa0Hundreds of commercial, military, and research satellites now orbit relatively close by, in low-Earth orbit. Others lie in safer geosynchronous orbit, visible here as the ring of dots circling farthest from the Earth.nIllustration: John MacNeilln

The blast wave from such an explosion would be insignificant, and even the powerful pulse of X-rays would affect only those satellites near the blast site. But many of the high-energy electrons from the products of nuclear fission would be trapped in the Van Allen radiation belts, degrading almost all satellites in LEO over the course of several months.

To initiate a high-altitude nuclear burst, a country must be willing to forgo its own space assets (or have few such assets to begin with). But the attack could do significant damage to valuable LEO satellites, including most military reconnaissance, surveillance, and intelligence satellites, as well as commercial and research satellites used for imaging and communication.

The means for such an attack already exist, in the form of thousands of Soviet-designed Scud missiles. The Scud-C, for example, sold by North Korea to Syria and other states, has a horizontal range of 600 km with a 700-kg payload; fired vertically, a Scud-C could reach 300 km. The positions of most large satellites are tracked by amateur astronomers and others and are readily available on the Internet. Accordingly, even a country with modest resources would be able to launch a Scud or some other short-range missile on a nearly vertical trajectory, arranged so that the apogee is in the path of an approaching satellite.

A single satellite in LEO can be destroyed without a nuclear warheadxe2x80x94if, for instance, a Scud used a mild explosive or a gas puff to disperse a few hundred kilograms of sand or gravel in LEO. The cloud of debris, falling only 1 km in the initial 15 seconds, would gravely threaten any satellite passing through it at orbital speeds of about 27 000 km/hr.

The threat that microsatellites could pose to existing space systems is probably greater than their potential benefit to the United States as weapons. An adversary microsatellite could use two quite different modes to destroy a quarry satellite. The first is direct impact: placed in an orbit that nearly intersects with its quarryxe2x80x99s, the microsatellite could leisurely fire its booster rocket to convert a normal and nonthreatening 100-km miss into a direct collision.

Accelerating by just 0.1 km/s (an expenditure of 3 percent of the satellitexe2x80x99s mass as rocket fuel) will net a 100-km displacement in 1000 secondsxe2x80x94about one-fifth of an orbit period in LEO, and far too little time for the quarry satellitexe2x80x99s operators to take effective countermeasures. As the microsat approached the quarry, it might deploy a xe2x80x9clethality enhancement device,xe2x80x9d such as a net, to improve its chances of success. No short-range defense seems possible against such a high-speed intercept, unless the quarry satellite were capable of rapidly maneuvering out of harmxe2x80x99s way, or unless it deployed confusion devices, such as balloon reflectors, to prevent the microsatellite from homing in on it. Current satellite systems are not known to have these protective capabilities.

A microsatellite could also launch an explosive or a projectile. For instance, the quarry would be unable to elude a space mine hovering just tens of meters away and equipped with an explosively driven pellet weapon or shaped-charge projectile. The microsat could also be programmed to fire if blinded or disturbed.

Various defenses to microsats can be imagined. A quarry satellite could be outfitted with sensors capable of detecting small, low-speed satellites, or it might be equipped with specialized defensive vehicles (perhaps even a fleet of bodyguard microsatellites of its own) to repel approaching space mines without harming the quarry.

How easy would it be to detect and track such space mines, and thereby thwart their attack? The U.S. Air Force Space Command, headquartered at Peterson Air Force Base in Colorado, indicates that it xe2x80x9cis responsible for tracking objects larger than 10 centimeters orbiting Earthxe2x80x9d and currently tracks some 9000 such objects.

But even perfect tracking would reveal only after the fact which satellite or launch was responsible for destroying the quarry. A real defense would require additional measures, such as those described above. And it is unclear, at least to us, how proposed U.S. space weapons would protect themselves against such threats.

If space weapons are not our best hopexc2xa0for protecting valuable communications, imaging, and other satellites, what are the alternatives? One attractive solution that avoids the political, economic, and technical difficulties of space weapons would be to reduce our dependence on space assets.

Satellite communication, for instance, typically relies on large and expensive satellites, and the loss of even one of these would have a crippling effect. Although some defense satellites do have backups, the majority of U.S. commercial communications and imaging systems have little redundancy. But if communications instead were configured in a distributed, load-balancing network of smaller satellites, an attack on one node, or even several, would do little harm. Such a strategy would also protect against system failures, accidents, and other disruptions to satellite communications.

As an alternative to redundancy and distribution, existing communications and intelligence-gathering satellites could be enhanced temporarily with terrestrial and airborne measures using unmanned aerial vehicles (UAVs), piloted aircraft, high-altitude balloons, or even rockets [see illustration, xe2x80x9cNetworking on the Flyxe2x80x9d].

nNetworking On The Fly:xc2xa0High-altitude UAVs can supplement satellites during conflicts, relaying radio signals and intelligence imagery between headquarters and the battlefield.nIllustration: John MacNeilln

These strategies might also arouse far less international opposition than would the deployment of space weapons. Such backup systems could also be more effective in local conflicts than the satellite system at risk.

Take the Global Positioning System, which currently consists of 28 satellites in medium Earth orbit. An adversary might have an interest in denying GPS capability in a particular localexe2x80x94such as the battlefieldxe2x80x94but rarely in denying the service worldwide. Also, it is far easier to jam the weak GPS signal across a few hundred kilometers than to destroy several of the GPS satellites in their higher orbits. In effect, a handful of jammers would do as much damage to local U.S. capability as the destruction of the satellites themselves.

Space weapons would be useless in countering such a scenario. Instead, within the expected area of jamming, the United States could deploy a network of short-range GPS transmitters carried by high-altitude UAVs, balloons, or, if necessary, rockets. Such xe2x80x9cpseudolites,xe2x80x9d flying at altitudes of 20 to 30 km on UAVs or balloons, would use antennas to distribute a powerful GPS-like signal.

Pseudolites aboard sounding rockets, on the other hand, would have to be launched a few times a day to maintain a strong signal and would need large antennas to focus the energy on a small area. Either way, the pseudolites would effectively protect the real GPS network, because the enemy would not achieve its goal by destroying the satellites. In similar fashion, battlefield communications satellites could be replaced by radio relay transmitters aboard UAVs.

n Detonating a nuclear warhead in space would disable hundreds of satellites.n n

For imaging, UAVs could not only replace satellites but in many cases outperform their high-flying counterparts, as recent experiences in Iraq and Afghanistan have demonstrated. To begin with, UAVs can almost always get at least 10 times closer to an area of interest: a 20-cm mirror or lens on a UAV at 20 km above Earth would be equivalent to a 300-cm mirror aboard a satellite orbiting at 300 km. Furthermore, UAVs can linger over a site of interest, unlike satellites, and can carry a wider variety of imaging equipment, including optical, infrared, and advanced synthetic aperture radars, which can image through darkness and cloud cover. Beyond imaging, UAVs can readily track moving targets on the ground across an area of hundreds of kilometers.

On the other hand, satellites can and do provide global coverage that UAVs can never match. But most military operations are local. The real threats come from regional disruption, and those threats can be countered by regional alternatives.

Return now to the three potential roles for space weapons: protecting existing satellites, denying the hostile use of space, and projecting force worldwide. It is difficult to identify a space weapon that is more attractive than its competing terrestrial alternatives. Offensive space weapons face inherent limitations, including long distances to targets and high energy requirements, which suggest in many circumstances a non-space-based alternative, such as forward-deployed missiles and conventional ICBMs. In nearly every case, space weapons are more complex, more costly, and less effective than Earth-based weapons.

Moreover, we have seen that there are a number of ways to render military space systems inoperable without destroying the satellites themselves, such as attacks on their ground stations. In such cases, space weapons would be rendered useless. We have also argued that satellites could be better protected with redundant systems that would mitigate attacks or with stand-in capabilities provided by UAVs or balloons above the battlefield.

As for denying adversaries the use of space, this may likewise be more readily achieved by less expensive terrestrial alternatives, such as electromagnetic jamming and the temporary blinding of adversariesxe2x80x99 reconnaissance systems.

The United States would prefer a world in which it alone had military space systems, weapons in space, and antisatellite capability. However, such a world never existed and never will. Already, several states and consortia have autonomous space-launch capabilities, among them Russia, China, Ukraine, Japan, India, and the European Union. Such groups would likely respond if the United States took a first step toward weaponizing space.

Consider, instead, a U.S. declaration that it would not be the first to deploy space weapons or to test destructive antisatellite systems, issued in parallel with an urgent challenge to negotiate an international treaty to this effect. From such a position, the United States could credibly declare that deploying space weapons would be regarded as a threat to U.S. security and that destruction of a U.S. satellite would be regarded as an attack on U.S. territory.

Even without space weapons, the United States could respond to an attack on its satellites with its unmatched terrestrial military capabilities. Adversaries would expect a heavy toll to be exacted as a result of any attack on U.S. satellites; that expectation alone would almost certainly suffice to deter any such attack.

In an all-out shooting war on Earth, we cannot expect that space would be a sanctuary for military systems supporting the weapons of that war. But the scenario sketched here, with the United States leading an urgent effort to ban space weapons and antisatellite tests or use, would help ensure that a shooting war on Earth would not be provoked by weapons in space.

This article opened with a fictional incident illustrating the appeal of space weapons. We will close by describing a possible outcome of such an incident, to offer a cautionary note about the risks and possible consequences of deploying space weapons.

12 June 2019xe2x80x94On the one-year anniversary of the destruction of the command and control center of the rogue nation, a U.S. congressional review commission releases its findings. The center suffered minimal damage, returning to 75 percent capacity within 30 days, suggesting that the rogue countryxe2x80x99s leadership had been expecting such an assault. Additionally, no illegal weapons of any kind were found on the airliner in question. Several months after the incident, one of the six orbiting U.S. space-based laser satellites inexplicably explodedxe2x80x94causing an international space-debris incident of its own. This satellite happened to be the same one that destroyed the launch facility, having thus revealed its location. Suspicions include an adversarial space mine, but the orbiting clouds of debris tell no tales.

The final conclusion of the congressional commission: the rogue countryxe2x80x99s leadership instigated the incident by feeding the United States disinformation. The United States came away having disclosed its deployment of space-based weapons, to international outcry, and the incident was widely portrayed as U.S. bullying. While it is surmised that the smaller country had a hand in destroying a $20xc2xa0billion U.S. satellite, its officials vigorously denied any role in the episode. In the end, the incident was recorded not as a measure of U.S. superiority in space but as a U.S. space debacle.

About The Authors

Bruce M. DeBlois is director of systems integration for BAE Systems, in Reston, Va. Richard L. Garwin (F) is IBM Fellow Emeritus at the Thomas J. Watson Research Center, Yorktown Heights, N.Y. (Correspondence should be addressed to him <a href=”mailto:atRLG2@us.ibm.com”>atRLG2@us.ibm.com</a>.) R. Scott Kemp is a member of the research staff of the Program on Science and Global Security at Princeton University, in New Jersey. Jeremy C. Marwell is a Furman Scholar at the New York University School of Law, in New York City. This article is based on work the authors did while at the Council on Foreign Relations.

To Probe Further

For a similar classification of space weapons, see a report by Bob Preston et al., xe2x80x9cSpace Weapons, Earth Wars,xe2x80x9d published by RAND Corp., MR-1209-AF (2002) and available online at http://www.rand.org/publications/MR/MR1209/.

xe2x80x9cReport of the Commission to Assess United States National Security Space Management and Organization,xe2x80x9d by Donald H. Rumsfeld et al., was published 11 January 2001. It is available online at http://www.fas.org/spp/military/commission/report.htm.

See also the report xe2x80x9cSpace Operations: Through the Looking Glass (Global Area Strike System),xe2x80x9d by Jamie G.G. Varni et al., published by the Air War College, Maxwell Air Force Base, August 1996.

The feasibility of space-based missile defense was assessed in xe2x80x9cReport of the APS Study Group on Boost-Phase Intercept Systems for National Missile Defense,xe2x80x9d published 15 July 2003. It is alsoxc2xa0available onlinexc2xa0[PDF].

Russiaxe2x80x99s military buildup along the border with Ukraine has clearly gotten the attention of policymakers from Kiev to Washington, D.C. CIA Director Bill Burns flew to Moscow to try to avert a crisis, while U.S. intelligence officials are reportedly warning NATO allies that a Russian invasion of large parts of Ukraine canxe2x80x99t be ruled out.

The possibility of Russian aggression against Ukraine would have huge consequences for European security. Perhaps even more concerning would be a Russian attack against a NATO member itself. Moscow might want to undermine security in the Baltic states or Poland, for instance, but could the Russian government successfully carry out a large-scale invasion of those countries? If recent wargames are any indication, then the answer is a resounding yes xe2x80x94 and it could do so pretty easily. In a 2016 War on the Rocks article, David A. Shlapak and Michael W. Johnson projected that the Russian army would overrun the Baltic states in three days.

Most of these wargames, such as RANDxe2x80x99s Baltic study, focus on fait accompli, an attack by the Russian government aimed at seizing terrain xe2x80x94 then quickly digging in. This creates a dilemma for NATO: launch a costly counter-attack and risk heavy casualties and possibly a nuclear crisis or accept a Russian fait accompli and undermine faith in the credibility of the alliance. Some analysts have argued that these seizures are much more likely to be small in size, limited to one or two towns. While that scenario should, of course, be studied, the concern about the feasibility of a fait accompli in the form of a major invasion still stands.

While the Russian army definitely has the combat power to achieve these scenarios, does Russia have the logistics force structure to support these operations? The short answer is not in the timelines envisioned by Western wargames. In an initial offensive xe2x80x94 depending on the fighting involved xe2x80x94 Russian forces might reach early objectives, but logistics would impose requirements for operational pauses. As a result, a large land grab is unrealistic as a fait accompli. The Russian army has the combat power to capture the objectives envisioned in a fait accompli scenario, but it does not have the logistic forces to do it in a single push without a logistical pause to reset its sustainment infrastructure. The Russian Aerospace Forces (with a sizable tactical bomber and attack aircraft force) and attack helicopters can also pick up fire support to alleviate artillery ammunition consumption.

NATO planners should develop plans focusing on exploiting Russian logistic challenges rather than trying to address the disparity in combat power. This involves drawing the Russian army deep into NATO territory and stretching Russian supply lines to the maximum while targeting logistics and transportation infrastructure such as trucks, railroad bridges, and pipelines. Committing to a decisive battle at the frontier would play directly into Russian hands, allowing a shorter supply to compensate for their logistic shortfalls.

Railroads and Russian Logistics Capabilities

Russian army logistics forces are not designed for a large-scale ground offensive far from their railroads. Inside maneuver units, Russian sustainment units are a size lower than their Western counterparts. Only brigades have an equivalent logistics capability, but itxe2x80x99s not an exact comparison. Russian formations have only three-quarters the number of combat vehicles as their U.S. counterparts but almost three times as much artillery. On paper (not all brigades have a full number of battalions), Russian brigades have two artillery battalions, a rocket battalion, and two air defense battalions per brigade as opposed to one artillery battalion and an attached air defense company per U.S. brigade. As a result of extra artillery and air defense battalions, the Russian logistics requirements are much larger than their U.S. counterparts.

Additionally, the Russian army doesnxe2x80x99t have sufficient sustainment brigades xe2x80x94 or material-technical support brigades, as they call them xe2x80x94 for each of their combined arms armies. A look into Military Balance, published by the International Institute for Strategic Studies, shows 10 material-technical support brigades supporting 11 combined arms armies, one tank army, and four army corps. Russiaxe2x80x99s Western and Southern Commands each have three armies and three material-technical support brigades to support them. In defensive operations, a Russian brigade can pull directly from the railhead. A trump card the Russians have are their 10 railroad brigades, which have no Western equivalents. They specialize in railroad security, construction, and repair, while rolling stock is provided by civilian state companies.

The reason Russia is unique in having railroad brigades is that logistically, Russian forces are tied to railroad from factory to army depot and to combined arms army and, where possible, to the division/brigade level. No other European nation uses railroads to the extent that the Russian army does. Part of the reason is that Russia is so vast xe2x80x94 over 6,000 miles from one end to the other. The rub is that Russian railroads are a wider gauge than the rest of Europe. Only former Soviet nations and Finland still use the Russian standard xe2x80x94 this includes the Baltic states. There are several railheads prior to Baltic capitals, but it will still take several days to reach and establish railhead operations. Forward railhead operations are more than just cross-loading cargo from train onto truck. It involves receiving and sorting cargo, repackaging for specific units, and storing excess on the ground. Due to the hazardous nature of military cargo, the ground needs to be prepared so that cargo can be stored in safe, distributed environments. This process can take one to three days. The site also needs to be outside the range of enemy artillery and secured from partisans. A single lucky shell or an rocket propelled grenade can result in a major explosion and have a disproportionate effect on the tempo of an entire division. This is assuming the key bridges, such as one at Narva on the Russian-Estonian border, arenxe2x80x99t destroyed and have to be repaired. Poland only has one wide gauge rail line, which runs from the Krakow region to Ukraine and canxe2x80x99t be used by Russian forces, without capturing Ukraine first. There are no wide gauge lines running from Belarus to Warsaw. Rail traffic moving across borders usually stops to cross-load cargo or uses adjustable railroad carriages and switches engines (which cannot adjust). In times of war, it is highly unlikely that the Russian army would capture enough Western train engines to support their army, forcing them to rely on trucks. This means that Russian army rail sustainment capability ends at the borders of the former Soviet Union. Trying to resupply the Russian army beyond the Russian gauge rail network would force them to rely mostly on their truck force until railroad troops could reconfigure/repair the railroad or build a new one.

Russiaxe2x80x99s truck logistic support, which would be crucial in an invasion of Eastern Europe, is limited by the number of trucks and range of operations. It is possible to calculate how far trucks can operate using simple beer math. Assuming the existing road network can support 45 mph speeds, a single truck can make three trips a day at up to a 45-mile range: One hours to load, one hour to drive to the supported unit, one hours to unload, and another hour to return to base. Repeating this cycle three times equals 12 hours total. The rest of the day is dedicated to truck maintenance, meals, refueling, weapons cleaning, and sleeping. Increase the distance to 90 miles, and the truck can make two trips daily. At 180 miles, the same truck is down to one trip a day. These assumptions wonxe2x80x99t work in rough terrain or where there is limited/damaged infrastructure. If an army has just enough trucks to sustain itself at a 45-mile distance, then at 90 miles, the throughput will be 33 percent lower. At 180 miles, it will be down by 66 percent. The further you push from supply dumps, the fewer supplies you can replace in a single day.

The Russian army does not have enough trucks to meet its logistic requirement more than 90 miles beyond supply dumps. To reach a 180-mile range, the Russian army would have to double truck allocation to 400 trucks for each of the material-technical support brigades. To gain familiarity with Russian logistic requirements and lift resources, a useful starting point is the Russian combined arms army. They all have different force structures, but on paper, each combined army is assigned a material-technical support brigade. Each material-technical support brigade has two truck battalions with a total of 150 general cargo trucks with 50 trailers and 260 specialized trucks per brigade. The Russian army makes heavy use of tube and rocket artillery fire, and rocket ammunition is very bulky. Although each army is different, there are usually 56 to 90 multiple launch rocket system launchers in an army. Replenishing each launcher takes up the entire bed of the truck. If the combined arms army fired a single volley, it would require 56 to 90 trucks just to replenish rocket ammunition. That is about a half of a dry cargo truck force in the material-technical support brigade just to replace one volley of rockets. There is also between six to nine tube artillery battalions, nine air defense artillery battalions, 12 mechanized and recon battalions, three to five tank battalions, mortars, anti-tank missiles, and small arms ammunition xe2x80x94 not to mention, food, engineering, medical supplies, and so on. Those requirements are harder to estimate, but the potential resupply requirements are substantial. The Russian army force needs a lot of trucks just for ammunition and dry cargo replenishment.

For fuel and water sustainment, each material-technical support brigade has a tactical pipeline battalion. These have lower throughput than their Western equivalents but can be emplaced within three to four days of occupying new terrain. Until then, fuel trucks are required for operational resupply. One might argue that the Russian army has the range to reach its objectives on their original tank of fuel, especially with auxiliary fuel drums they are designed to carry. That is not entirely correct. Tanks and armored vehicles burn through fuel when maneuvering in combat or just idling while stationary. This is the reason why the U.S. Army uses xe2x80x9cdays of supplyxe2x80x9d to plan fuel consumption, not range. If a Russian army operation lasts 36 to 72 hours as the RAND study estimates, then the Russian army would have to refuel at least once before tactical pipelines are established to support operations.

Sustaining Logistics Is the Hard Part

A Scenario in the Baltics

There are serious logistic challenges with large-scale fait accompli operations in the Baltics. Small scale fait accompli operations are feasible with small forces without a logistical challenge but on a large scale are far more challenging. Fait accompli requires Russian forces to overrun Baltic states and eliminate all resistance in less than 96 hours xe2x80x94 before NATOxe2x80x99s Very High Readiness Task Force can reinforce the defenders. This force wonxe2x80x99t stop a Russian attack, but it commits NATO to a land war, negating the very purpose of fait accompli.

Logistics are the key stumbling block in the fait accompli timeline. The railroad is wide gauge and usable, but the timeline is too short for captured railheads to be put back into operation. A dozen NATO air-launched cruise missiles fired over Germany can destroy key rail bridges at Narva, Pskov, and Velikie Lugi, shutting down rail traffic into the Baltics for days until those bridges are repaired. Logistic planners in Russian Western Command have to plan for a scenario in which Baltic states choose to fight a battle in their capital. Historically, urban combat consumes massive amounts of ammunition and takes months to conclude. During the two most prominent examples, the battles of Grozny in the Chechen wars and the Battle of Mosul in 2016, defenders tied down four to 10 times their numbers for up to four months. At Grozny, Russians were firing up to 4,000 shells a day xe2x80x94 thatxe2x80x99s 50 trucks a day.

Even in a Baltic scenario, Russian planners have to consider the risk that Poland, which can muster four divisions, will launch an immediate counter-attack, trying to catch the Russian army off-balance. The Russian army would have large forces tied to sieges of Tallinn and Riga while fending off a Polish counter-attack from the south. The ammunition consumption would be massive. During the 2008 Russo-Georgian War, some Russian forces expended an entire basic load of ammunition in 12 hours. Assuming the same rates, the Russians would have to replace substantial amounts of ammunition every 12 to 24 hours.

Herein lies the dilemma. Overwhelming local forces in the Baltics before NATO troops arrive does not give Russia time to establish railheads, forcing reliance on trucks. At 130 miles, they can only do one trip a day, generating a truck shortage. Russian planners could commit fewer maneuver forces and risk failing to overwhelm defenders. Alternatively, they could take a logistics pause for two to three days and give the Baltic states time to mobilize and NATOxe2x80x99s Very High Readiness Joint Task Force time to arrive. Meanwhile, they would be taking attrition from local partisans, NATO airstrikes, maintenance breakdowns, and loitering munition as seen in the latest Nagorno-Karabakh War. Either way, fait accompli fails, and conflict degenerates into protracted war, which Russia is likely to lose. Russian logistics can only support a large-scale fait accompli if NATO forces fight a decisive battle at the frontier. The bulk of supply consumption would take place close to Russian depots. Russian air forces can alleviate the logistic strain by taking on fire support. Whatxe2x80x99s uncertain is how long the Russian air force would provide close air support in the face of NATO airpower, given NATOxe2x80x99s ability to conduct standoff air-to-air engagements with long-range missiles from beyond the effective range of Russian air defense in Kaliningrad and St. Petersburg. A similar picture exists at sea. The combination of airpower, diesel submarines, and shore-based anti-ship missiles is likely to deny the Baltic Sea to surface fleets of both sides.

The Russian army has ample combat power to capture the Baltic states, but it wonxe2x80x99t be a rapid fait accompli unless the Russian government scales down the size of the territory it wishes to seize. Using Van Jacksonxe2x80x99s 2xc3x972 xe2x80x9cVariations of Fait Accomplixe2x80x9d diagram as a conceptual framework, we can fully appreciate the Russian dilemma. The logistic forces can only support a gradual fait accompli, which wonxe2x80x99t shatter NATO unity, instead giving NATO time to mobilize and seal off the land grab. Even if NATO chooses not to reconquer the territory right away, its member states would likely impose crippling economic sanctions until Russia caves in. On the other hand, the decisive fait accompli, such as the conquest of a full member state, may achieve the objective of shattering NATO unity, but it canxe2x80x99t be logistically supported by the Russian army. It also runs a major risk of miscalculation by assuming that all thirty member states have to declare NATO Article 5. On paper, thatxe2x80x99s true, but in practice, only the United States (to provide combat power), Germany, and Poland (to secure access) have to honor Article 5, and Russia would find itself in a major conflict that can escalate beyond the nuclear threshold.

A Polish Scenario

The Russian armyxe2x80x99s logistic challenges are different in a Polish scenario. There are fewer time constraints but greater difficulties due to the distances involved and lack of wide gauge railroads, which end at the Belarusian border. The closest railhead to Poland is Grodno and Brest in Belarus. The first is located 130 miles and the second 177 miles from Warsaw. For an army that is stretched to sustain 90 miles, that is a long supply line to support.

Kaliningrad could be considered as another option, but it is not practical, as it is landlocked by NATO members. The combination of NATO airpower, naval forces, and Polish land-based anti-ship missiles make resupply by sea unlikely. According to Military Balance, there is a Russian corps with major depots but no supporting logistics units to push supplies out. Maneuver forces would have to pull these supplies using organic logistic formations, a range of about 45 miles. The garrison there can hold out in isolation for a long time but cannot conduct ground offensive operations. The Russian army will be able to reach Warsaw but cannot capture it without a logistic pause to halt, reconfigure/repair the railroad, and build tactical pipelines and frontline depots. Instead of pausing for a couple of days as in the Baltic scenario, the pause in the Polish scenario could take up to a couple of weeks. This gives NATO breathing space to build combat power.

The logistics are also useful to assess a Ukrainian conflict as Russian forces are again massing on the border. The best means of interpreting the seriousness of Russian intentions is to track the buildup of logistic forces and supply dumps rather than count battalion tactical groups that have moved to the border. The size and scale of logistic preparation tell us exactly how far and deep is Russian army planning to go.

Russian Strategic Reserves

Russia could reinforce its Western Joint Strategic Command (Western Military district) from other parts of the country to increase logistic power, but not by much. As Michael Kofman has pointed out, NATO has the ability to horizontally escalate the conflict by holding most Russian theaters at risk. The Russian General Staff cannot ignore this threat. As a result, Russiaxe2x80x99s Central Command and parts of the Eastern Command are the only joint commands not facing an external threat and are able to reinforce Western Command. However, the sustainment forces they provide would be consumed by the additional combat forces that come with it. There are no extra trucks in the Russian army that are not tied to supporting engaged forces.

One of the strengths of the Russian army in a war in the Baltics or Poland would be its ability to mobilize reservists and civilian trucks. Russia still has a massive mobilization capacity built into its national economy, a legacy of World War II and the Cold War. However, mobilizing civilians to fight a war has major economic and political costs. To maintain political stability at home, the Russian people would have to genuinely believe they are defending their country. They will not tolerate husbands, sons, and fathers going off to a war on Putinxe2x80x99s whim. The last time the Russian government heavily relied on conscripts and reservists was during the First Chechen War (1994xe2x80x931996). Within two months, a major antiwar movement appeared, spearheaded by soldiersxe2x80x99 mothers.

Russia and the Fait Accompli

The Russian army will be hard-pressed to conduct a ground offensive of more than 90 miles beyond the borders of the former Soviet Union without a logistics pause. For NATO, it means it can worry less about a major Russian invasion of the Baltic states or Poland and a greater focus on exploiting Russian logistic challenges by drawing Russian forces further away from their supply depots and targeting chokepoints in the Russian logistic infrastructure and logistic force in general. It also means that Russia is more likely to seize small parts of enemy territory under its logistically sustainable range of 90 miles rather than a major invasion as part of a fait accompli strategy.

From the Russian perspective, it does not appear that they are building their logistic forces with fait accompli or blitzkrieg across Poland in mind. Instead, the Russian government has built an ideal army for their strategy of xe2x80x9cActive Defense.xe2x80x9d The Russian government has built armed forces highly capable of fighting on home soil or near its frontier and striking deep with long-range fires. However, they are not capable of a sustained ground offensive far beyond Russian railroads without a major logistical halt or a massive mobilization of reserves.

Deciphering Russiaxe2x80x99s intentions right now is increasingly difficult. Its military buildup on the border with Ukraine could be preparation for an invasion or it could be yet another round of coercive diplomacy. Nevertheless, thinking through Russiaxe2x80x99s military logistics capabilities could give NATO some insights into what Moscow might be planning to do next xe2x80x94 and what the Western alliance might do to protect its interests.

Lt. Col. Alex Vershinin commissioned as a second lieutenant, branched armor, in 2002. He has 10 years of frontline experience in Korea, Iraq, and Afghanistan, including four combat tours. Since 2014, he has worked as a modeling and simulations officer in concept development and experimentation field for NATO and the U.S. Army, including a tour at the U.S. Army Sustainment Battle Lab, where he led the experimentation scenario team.

Correction: A previous version of this article stated that Russiaxe2x80x99s Western and Southern Commands each have three armies and only two material-technical support brigades to support them. In fact, those districts have three material-technical support brigades.

Image: Russian Ministry of Defence

Russian military shifts and stinging Kremlin criticisms of Ukraine are raising questions about Moscow’s aims. In 2014, Russia’s seizure and annexation of Crimea and invasion of eastern Ukraine led to a strong Western responsexe2x80x94a jump in military aid to Ukraine, a NATO buildup on its eastern flank, and unprecedented sanctions. What could be in store now?

There are multiple reasons to be wary.

On November 1, Politico reported that satellite images showed a xe2x80x9cbuildup of armored units,xe2x80x9d tanks, and self-propelled artillery in Russia near Belarus, and a relocation of tanks from near Moscow to Ukraine’s border. President Biden’s security advisor, Jake Sullivan, said the United States was consulting with allies and partners.

Earlier Russian military actions also spurred unease. In September, Russia and Belarus conducted a huge Zapad-21 military exercise, xe2x80x9cfar more robustxe2x80x9d than one four years prior. Last spring in an out-of-cycle move, Russia shifted substantial forces closer to Ukraine and into Crimea. The U.S. European Command raised its alert level, and U.S. Chairman of the Joint Chiefs of Staff Mark Milley called Russian Chief of the General Staff Valery Gerasimov.

Kremlin rebukes also cause anxiety. On November 1, Foreign Minister Sergei Lavrov warned of xe2x80x9cattempts to carry out provocationsxe2x80xa6and drag Russia into some kind of combat.xe2x80x9d Some in the West might see this as cover for renewed aggression. On October 22, Russian President Vladimir Putin said a visit by Secretary of Defense Lloyd Austin to Ukraine had xe2x80x9copened doorsxe2x80x9d for it to join NATO. This is a distant prospect. Putin aide Dmitri Medvedev claims Ukraine’s leaders are hostage to xe2x80x9crabidxe2x80x9d nationalist forces, which is erroneous.

That said, the Kremlin’s intentions regarding Ukraine remain uncertain. Some earlier troubling signs did not presage imminent threats. On November 3, Gen. Milley described Russian movements as not xe2x80x9covertly aggressive.xe2x80x9d On November 8, however, CNN reported that earlier in the week in Moscow, Central Intelligence Agency Director William Burns had voiced xe2x80x9cseriousxe2x80x9d concerns to Putin about Russia’s military buildup along Ukraine’s border. And on November 10, Secretary of State Antony Blinken warned Moscow against making a xe2x80x9cserious mistakexe2x80x9d in Ukraine.

Perhaps Moscow seeks only to discourage further Western military support for Ukraine. But if Russia were to heighten threats, the West could take stronger measures. Those the West took after 2014 might hint at how the West could raise costs to Russia.

The United States and NATO have provided substantial training, equipment, and advisory assistance to Ukraine. The United States has sent modern armed patrol boats and portable Javelin missiles, lethal against Russian tanks. In September, the United States announced further aid in response to the xe2x80x9cmajor increase in Russian military activityxe2x80x9d along Ukraine’s border.

A second Western response has been NATO’s eastern build-up of forces. It now rotates four battalion-sized land combat units to Estonia, Latvia, Lithuania, and Poland. A multinational brigade, including air power, rotates to Romania. Since 2014, the United States has spent billions of dollars (PDF) to enhance collective security in Europe.

A third dimension of the Western response is sanctions. They might have reduced Russia’s economic growth by as much as 2.5-to-3.0 percent per year. Sanctions combined with the pushback by Ukrainian fighters against Russian forces in summer 2014 in eastern Ukraine might have helped dissuade the Kremlin from attempting to take all of eastern and southern Ukraine. The Kremlin had hinted that its goal was to seize what it calls Novorossiya.

If it were to become necessary, what new steps might the West consider?

One may be supplying a wider range of lethal weaponry. The U.S. House Committee on Armed Services has called for a Biden administration report on how to help Ukraine address air and missile defense gaps. The United States could send Ukraine portable Stinger air defenses or Iron Dome defenses against short-range missiles.

NATO could further buttress eastern defenses. A RAND study found that at present xe2x80x9cNATO cannot successfully defend the territory of its most exposed members.xe2x80x9d Wargaming suggests that a force of seven brigades could prevent a xe2x80x9crapid overrunxe2x80x9d of the Baltics. This might involve an order of magnitude more combat power. NATO states could also send more warships into the Black Sea, subject to limits in the Montreux Convention.

Tougher sanctions might be a third response. Sen.Lindsey Graham (R-S.C.) warns of xe2x80x9csanctions from hell.xe2x80x9d In 2017 by near-unanimous votes in both chambers, Congress passed a sweeping sanctions bill aimed mainly at Russia. A recent Biden administration review cautioned that economic and financial sanctions are best used in xe2x80x9ccollaboration with our allies (PDF).xe2x80x9d In 2014, such coordination with Europe amplified the effect of Western sanctions.

Now is probably not the best time to be breathless about the risk of increased Russian threats in Ukraine. This may, or may not, be Moscow’s purpose. But the West will be watching.

William Courtney is an adjunct senior fellow at the nonprofit, nonpartisan RAND Corporation and a former U.S. ambassador to Kazakhstan, Georgia, and the U.S.-Soviet commission to implement the Threshold Test Ban Treaty.

This commentary originally appeared on The Hill on November 13, 2021. Commentary gives RAND researchers a platform to convey insights based on their professional expertise and often on their peer-reviewed research and analysis.