The establishment of the United States Space Force tells us that we really do live in a science fiction world.

For nearly forty years, the United States Air Force has had a Space Command.  Now that organization is being upgraded to an independent military service.  For the time being, the Space Force will report to the secretary of the Air Force.  The arrangement is much like that of the Marine Corps, which reports to the secretary of the Navy.  However, we can envision that in a few years, the Space Force will split from the Air Force and become truly coequal with the senior services.  This evolution likely will follow the history of the birth of the Air Force. 

The Air Force formally started in 1926 as a subsidiary branch of the Army known as the Air Corps.  Our anticipated involvement in the Second World War required a great expansion of our air arm.  So, in 1941, the Air Corps was elevated to become the Army Air Force, which now reported directly to the Army chief of staff.  In 1947, the Air Force was separated from the Army and made into a coequal service.  We can reasonably expect the same thing to happen to the Space Force as its role progressively expands.

Why do we need a Space Force?  The reason is that far and away our nation's greatest vulnerability now lies on the space frontier.  This has been true for more than six decades, beginning with the advent of the nuclear-tipped intercontinental ballistic missile. 

An ICBM is a weapon that attacks from space.  During its flight, an ICBM follows an elliptical orbit around the Earth.  It is based on land for convenience and because of arms control (proper control, I might add).

We have learned to live with ICBMs as a deterrent to all out war.  In the meantime, the U.S. has developed major space frontier vulnerabilities of a completely different kind.  Space has become the purveyor of information that we need for our very survival. 

There are three types of information that have become critical: 1) observation of activities on Earth and in space, 2) secure communications, and 3) Global Positioning System navigation and timing.

Observation of the Earth, with imaging and with electronic surveillance, is critical to military operations.  Aviation became essential during the First World War because of aerial observation.  The French checked the German advance in the first Battle of the Marne because aerial observation reported that the Germans were unexpectedly close to Paris.  This convinced the allies that aerial reconnaissance was essential.  Full-scale aerial warfare quickly developed as a consequence.  If aerial observation was critical a century ago, its modern extensions into space are even more important today.  Observation of objects resident in space is equally critical — mainly to avoid surprise and to facilitate response.

Secure battlespace communications have become essential.  A major focus of satellite communications is to link all battle participants with secure communications and instantaneous universal data transfer.  Space dominance and security are critical for this kind of network.

GPS originally was developed just to help with navigation.  Now, because of GPS's precision, it is the key operational element on the battlefield and elsewhere.  Modern precision munitions and coordinated battle activities all depend on GPS.  Without GPS, we revert to Vietnam-era operations.

While these various functions are essential for modern military operations, they have become equally essential in the civilian arena as well.  To take just one example out of many, GPS provides the critical timing information needed to synchronize today's communications.  Without GPS, the stock market, the banking system, and the cell phone network all would collapse, and the United States would be thrown into chaos and a deep depression. 

A space-based defense is therefore essential to protect the economy of the United States.  We need a Space Force with the military muscle to destroy any threat to our vital space assets.  This means deploying weapons in orbit. 

Nuclear weapons are limited by treaty and by deterrence.  But conventional weapons in space are not so constrained.  Conventional space munitions already exist.  Weapons to intercept satellites have been tested by the U.S. and China and, it is believed, by Russia.  Exo-atmospheric missile interceptors are also space munitions.  It is only a small extension to actually station munitions in orbit.  The first generation of orbit-based weapons will be for missile defense.  Orbital conventional weapons with the ability to hit targets down on the Earth will inevitably follow.

Operations on land, sea, and air have great freedom of movement.  Armies can move over most of the Earth's land.  The Navy's ships sail over, or under, all the world's seas.  The atmosphere is everywhere accessible to aircraft.  Space is qualitatively different.  Movement in space is highly constrained.

An orbiting spacecraft can't fly freely around.  Energy expenditure determines what can be done.  Orbits are best defined by an orbit's inclination angle.  Once in orbit, changing that angle requires a great deal of energy.  Thus, some maneuvers are easy, and others are hard.  This constrains space combat.

A satellite's orbital elements are predictable.  It is difficult for spacecraft to do the unexpected — particularly if the spacecraft is continuously observed.  This orbit predictability and inflexibility has important military implications.

Despite these tactical restrictions, constellations of satellites have major advantages.  Once in orbit, satellites need almost no further expenditure of energy.  Usually twice a day each spacecraft will visit almost all locations on the Earth.  Individual satellites come and go, but a dense enough constellation is persistent.  It is always there, watching, waiting, everywhere.  A dense constellation has instantaneous access to any point on the Earth.  This has profound implications for war.

This constellation characteristic means that space-based defenses can permanently eliminate the threat from nuclear-tipped ballistic missiles and from newly emerging hypersonic vehicles as well.  Nuclear warheads can most easily be destroyed when their rockets are in the boost phase.  Then they are extremely vulnerable.  Boost phase defense requires weapons in space.  High-energy lasers — i.e., ray guns — are likely to be the preferred weapon for boost phase kills.  Hypersonic vehicles are extremely hot, and their infrared signatures will be easily visible from space.  These vehicles will be vulnerable to kinetic munitions delivered from orbit. 

An aircraft-launched munition may cost millions of dollars.  But this cost is usually trivial compared to the cost of getting the aircraft to the release point.  The material cost of a war is not the cost of the munitions; it is the cost of the logistics.

This is where space has an enormous advantage.  A constellation of orbiting military spacecraft can be everywhere all the time!  Kinetic munitions, stored in a constellation of spacecraft, can be delivered to a target any place on Earth, or above the Earth, within minutes after a fire order.  In the case of a laser defense against ICBMs, the reaction time is seconds.  Thus, once the initial investment has been made to place these devices in orbit, there is almost no further logistics cost. 

Given the logistics, time, and cost advantages of space-based weapons, the Space Force will have the most profound impact on both international relations and their fellow services: major conventional conflicts would be deterred by non-nuclear means.  Armed space forces would render obsolete almost all mass military forces.  Eventually, when space force parity is reached among adversaries, armies and surface navies will diminish into specialty forces; they are too vulnerable to attack from space.  In the realm of diplomacy, bilateral agreements will likely supersede today's multinational defensive coalitions like NATO. 

There will still be conflicts and killing.  But these conflicts will almost completely take the form of special forces warfare, urban warfare, and cyber-warfare — the point being that you must be invisible from space.

Combat in space between fleets of spacecraft will be possible, even though such combat will be very difficult and attritional.  The orbital constraints make it almost impossible to synchronize mass attacks by kinetic munitions, or even by lasers. 

The military world of the not too distant future is likely to resemble old-time space-opera science fiction.  It is easy to see why establishing the U.S. Space Force was inevitable.