Once upon a time, Ronald Reagan inaugurated America's Strategic Defense Initiative, a missile defense program that critics immediately derided as "Star Wars" -- pure fantasy.

Ronald Reagan's "Star Wars." Artist's concept: Wikimedia Commons.

Don't look now, but Star Wars is coming to life today -- and Boeing (NYSE:BA) and Lockheed Martin (NYSE:LMT) are helping to lead the way.

Star Wars tech
By now you're probably all up to speed on the many advances U.S. defense companies have made in the field of laser weapons. You know that the U.S. Marine Corps is developing a "Ground Based Air Defense" energy weapon, and that Lockheed Martin just demoed a "High-Energy Laser Mobile Demonstrator" that can melt a pickup truck at 30 paces. You've certainly heard about the U.S. Navy's drone-blasting Laser Weapon System  -- already deployed to the Persian Gulf.

Video still: U.S. Navy..

But did you know that laser guns are just the beginning of the Pentagon's Star Wars-ian aspirations? Did you know we're also developing a new generation of force fields, and even cloaking devices?

Force fields are real
It's true. Earlier this year, Boeing obtained a patent from the U.S. Patent and Trademark Office for a rudimentary "force field" defensive system, as illustrated in the following drawing:

Boeing Patent 8,981,261 B1 depicts the operation of a rudimentary force field. Source: U.S. Patent and Trademark Office..

Boeing's technology works like this: An armored vehicle equipped with the system detects an explosion nearby and calculates the exact instant that the shock wave from the explosion will strike the vehicle. The system fires lasers at a patch of air betwixt explosion and vehicle, superheating the air into a plasma -- the "force field" in question -- which disrupts and deflects the shock wave, protecting the vehicle from harm.

Now, Boeing's system is at best a "beta" version of a real force field. It won't stop shrapnel, for example, much less a missile coming in on a collision course. But other companies are hard at work devising defenses that might do that.

Over in Britain, for example, the local version of our own DARPA is called the Defence Science and Technology Laboratory. DSTL has found a way to electrify a tank's armor, forming an instantaneous force field that can vaporize incoming projectiles as big as an RPG round before they penetrate to the vehicle's interior.

DSTL says the amount of electric power needed to achieve this effect is "surprisingly small." And once fully matured, this tech could reduce the amount of armor a vehicle must carry to protect itself, cutting vehicle weight by as much as 70%, and reducing vehicle cost, fuel consumption, and transportation cost proportionally.

You call that "stealth"? We'll show you stealth.
High-tech and whiz-bang as this all sounds, the electrical engineers at University of California, San Diego, may have just eclipsed it with a new invention that improves upon Lockheed Martin's existing "stealth" technology. Defense Update describes it as a "cloaking device," incorporating ceramic nanocylinders into a Teflon substrate to create an ultra-thin "skin" that can cover a tank, an airplane, or a spaceship -- rendering it invisible in certain spectra.

Designed one way, this cloaking device could render an object invisible to radar. Tweak the design, and it could be invisible, period. As this research matures, a future skin might be devised to do both at once -- and create an all-purpose cloaking device.

A cloaking device bends light waves around it, redirecting them such that a cloaked object appears to be "not there." Illustration: Wikimedia Commons.

But what does all this mean to investors?
Here at The Motley Fool, we're as interested as anyone else in keeping up with developments in the military-industrial complex. But what we really enjoy is figuring out how these advances might affect investors' portfolios. So here's how we look at this "Star Wars" story:

Two of the biggest logistical problems the U.S. military faces are getting supplies ("bullets") to its shooters, and ensuring there are always bullets on hand when and where they're needed. Laser weapons solve both of these dilemmas by permitting laser "bullets" to be created on the spot, from electricity generated by a military vehicle.  

A third dilemma involves not bullets, but "billions." Specifically, the billions of dollars spent funding America's military every year -- billions that are increasingly hard to come by in tight budgetary times.

If one shot from a laser cannon can replace one launch of a Rolling Airframe Missile, and if that one shot costs less than $1, while the RAM costs $1 million, then the military theoretically saves $1 million every time it fires a laser instead of launching a missile. Savings of this magnitude justify an almost infinite amount of investment into making laser weapons a reality, because the payoff will be so big. For this reason, I'm convinced that the Pentagon's first priority in maturing "Star Wars" tech will be to develop and roll out laser weapons across all four branches of the military.

Investments in force fields and in cloaking devices are another matter. On one hand, they have the potential to become dramatic force multipliers for U.S. military units. By making it harder for adversaries to locate and destroy multimillion-dollar tanks, aircraft, warships, and spaceships, they'll also save us money in the long run. But both of these defensive technologies are at earlier stages in their development -- and offer the Pentagon less obvious, immediate cost savings than do laser weapons.

The upshot for investors? Force fields and cloaking devices are fun to read about and capture our imagination. But don't get too excited about them. in the immediate future, the real money to be made from "Star Wars" tech remains in lasers. Lucky for us, we also know a lot more about which companies are dominating this field -- and are deserving of our investment.

More laser-weapon art. Source: Wikimedia Commons.