How does the old saying go? “If you can’t beat ‘em, build a mechanical exoskeleton and then beat ‘em?” That’s the military strategy in Tom Cruise’s latest sci-fi action film, Edge of Tomorrow.

In nature, when a predator is stronger, faster, and better equipped than the prey, it kicks off an evolutionary arms race. Over millions of years, prey evolves better defenses like camouflage or poison, and predators keep up with claws and teeth. In Edge of Tomorrow, Tom Cruise and Emily Blunt don’t have a million years to adapt to a fearsome new predator. Humanity decides that the only way to stop the world-conquering “mimics” (aside from some spoilery details) is to use human ingenuity to our advantage. That means augmenting human performance with “combat jackets.”

The Real Thing

You might expect a big-budget sci-fi film to use big-budget CGI while creating the combat jackets seen in Edge of Tomorrow, but you’d be wrong. Tom Cruise and costume designer Kate Hawley worked together with the rest of the “ExoSuit” team to create a physical suit—they wanted battle scenes to look as real and gritty as possible.

In other words, the suits weren’t just for show. Popular Science explained “the modeler, Pierre Bohanna, made each suit from 350 to 400 discrete components that together form a fully articulating device. The materials include standard nylon, high-grade aluminum, and a lightweight polymer created specifically for the film.”

So, the sweat you see on Cruise’s brow isn’t an effect—a finished suit could weigh between 100 to 135 pounds, and initially took Cruise and the other actors 30 minutes to get in and out of with the aid of four handlers, reports The Credits.

The whole process of design to final suit took five months.

The design team for Edge of Tomorrow took cues from the plans militaries and private companies have already made real, but just how far are we away from the alien-crushing battle jacket Emily Blunt dashes around in?

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The Edge of Tomorrow is set in “the near future,” which is good news if we do have to fend off alien invaders, because our exoskeleton technology is surprisingly advanced. Here are six suits already augmenting human abilities.

The XOS 2

Developed by Sarcos and then Raytheon, the XOS 2 robotics suit was developed under the US Defense Advanced Research Projects Agency’s (DARPA) exoskeleton research initiative in 2001. The XOS 2 enables the user to lift up to 200 pounds like he or she was lifting something much, much lighter. With hydraulic actuators controlled by computer, the suit has a 17:1 strength ratio, meaning that lifting a 50-pound object only feels like lifting under three pounds. It also lets you punch through three planks of wood and do a ton of push-ups, as you can watch below:

The HAL 5

The HAL 5 (Human Assistive Limb 5) is unique in that it was the first exosuit to attain global safety certification. Developed to help the disabled in hospital settings, the HAL 5 is already in use in some hospitals thanks to Cyberdyne (not the evil one that created terminators). Take a look at it in action:

The HULC

Lockheed Martin created the HULC (Human Universal Load Carrier) with soldiers in mind. The suit uses computer processors and a hydraulically-powered titanium frame to lighten the load soldiers have to carry. It weighs only 53 pounds, but it enables soldiers to carry much heavier loads, lift up to 200 pounds like it was nothing, and sustain three-mile per hour marches and 10 mile per hour sprints (for as long as the battery is charged). Aside from the XOS 2, the HULC is probably the closest exosuit we have to the battle jackets in Edge of Tomorrow.

The Body Extender

The PERCO Perceptual Robotics Lab created “the Body Extender,” apparently “the most complicated” exosuit developed so far. Looking almost exactly like the powerloader from Aliens, this machine has a 10:1 power ratio and enables the user to lift 50 kilograms with each arm (seriously impressive).

The Powerloader

Coming out in 2015, the Japanese robotics company ActiveLink developed a “Dual Arm Power Amplification Robot” which senses the motions of the user and acts accordingly, to make everything move fluidly. Check it out:

The ReWalk

Argo Medical Technologies helps lower-limb impaired people walk again with their ReWalk technology, which has already been approved in a number of world markets, and is currently being sold for personal use.

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Even more exosuits exist either on the market or in development (or in the military), but none of them will let you jump sideways 20 feet while launching rockets like Tom Cruise. Our current technology still has a few hurdles before it looks like Edge of Tomorrow.

First, we need better power systems. Exosuits work great when they are hooked up to an umbilical cord, much less so when they have to run on batteries. Today’s batteries just don’t hold a lot of energy and are too heavy. We haven’t had a breakthrough in battery technology for decades now, so perhaps an alien invasion would be just the push we would need to get post-lithium-ion.

Next, we need better materials. The fundamental engineering problem with an exosuit that is supposed to make you stronger is weight vs. strength. If you make an exosuit out of steel, you can put much bigger artificial muscles on it because the material is stronger. But steel is heavy, much heavier than aluminum, for example. Aluminum can’t hold as much as steel, but it significantly reduces the weight on the user. The solution to this problem is likely in non-traditional materials such as carbon fiber.

The weight vs. strength problem is only an issue when the motors and artificial muscles the exosuits use aren’t very efficient. If we could innovate a new muscle technology that increased power ratios far beyond what we are capable of now, lifting a car could be like lifting a feather. Then we would really be ready for the aliens.

Lastly, exosuits would have to be better at predicting our movements. The HAL 5 suit currently gets around this problem by attaching sensors to the skin of the user, letting the artificial muscles move as in-sync with the real muscles as possible. But for most full-body suits like HAL 5, there can be seconds of lag time. To speed everything up, suits could jack directly into our nervous systems, as in the film Elysium, with a brain-machine interface. These incredible augmentations interpret electrical signals directly from the brain and translate them into mechanical action. If we already can make one that allows a monkey to control a robotic arm, perhaps the next generation of exosuits can be just as mobile as we are.

Given how far militaries and private companies around the world have come so far, a mechanical exoskeleton could turn humans into supermen and superwomen relatively soon. Of course, an alien invasion would probably speed that process along.

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Kyle Hill is the Science Editor of the Nerdist enterprise. Follow the geekery on Twitter @Sci_Phile.

READ: Review: Edge of Tomorrow
WATCH: Tom Cruise and Chris Hardwick Talk EDGE OF TOMORROW