Recommendation: Go see it, but take advantage of the slow and predictable parts of the movie to watch the videos from the Cybathlon games for real-life cyborgs.
Alita: Battle Angel is a thoughtful movie. There’s plenty of time to think about the special effects, to note the cinematic similarities to The Matrix and Dark Angel, and to compose a tweet to Ed Skrein suggesting that he stop playing the British villain (really, Ed, it was cool in Deadpool but let’s move on). There’s also time for us to wonder why the movie was released on Valentine’s Day. Is this a date night movie for guys who think Tomb Raider is a chick flick? Or is it for 14-year old girls who will be, in theory, empowered by a strong female cyborg who gets a boob job as part of a body upgrade midway through the movie? Hard to say. Alita: Battle Angel is a bit like Solo: A Star Wars Story; it’s good but not great, fun but not joyous.
But, in terms of robotics, Alita: Battle Angel offers some thoughtful moments about robots and cyborgs. In real life, cyborgs generally fall under the purview of medical and rehabilitation robotics research. Medical and rehabilitation robotics has been an active area of research for decades, but really got a big push from the DARPA 2005 Rehabilitation Robotics challenge designed to help wounded soldiers.
One thought is that, no surprise, the movie glosses over the four big problems in prostheses. The biggest is how to coordinate the limb. Current technology for coordinating the movement a leg or an arm uses EMG signals from other muscles, but the real goal is a brain-machine interface. A second problem is designing prostheses that have an equivalent range of motion and sufficient power to at least duplicate human movement. Remember the intro to The Six Million Dollar Man: "We can rebuild him. We have the technology. We can make him better than he was. Better...stronger...faster.” Right now, it would be “We can make him almost as good as he was.” A third challenge is sensing: sensors are needed to make a prostheses able to move naturally and sensors are needed as replacement eyes and touch. The fourth challenge is how to build all of this in a way that guarantees safe operation; for example, that the prosthesis can’t get into a state that would trip the human or cause an injury.
Another thoughtful moment is that apparently 500 years into the future, it will STILL be hard to make prostheses that are both functional and cosmetic. In Alita: Battle Angel, the majority of prosthesis are big and bulky, smaller versions of Pacific Rim’s (see review on exoskeletons here) unnecessarily complex mechanisms, making the owner look to be in serious danger of toppling over from the added weight. Morphology is a current challenge in rehabilitation robotics: how to make limb replacement look natural but also work. However, the big emphasis, both by the injured and by researchers, is on replacements that “work”, not on ones that look natural.
A third thought is that in the future it will be great to be a cyborg because, although we won’t be able to build a natural-looking prosthesis, we will have resolved some of the existing legal issues about wearing one. Currently, it can be tough to be a cyborg. Neil Harbisson had to file a lawsuit in order to get a passport because the British government insisted he take off the camera that hangs over his forehead like an antenna. The camera detects colors and creates vibrations, so that Harbisson, who can only see in black and white, can “hear” colors. Harbisson’s beef with the government was that the antenna is surgically attached to his skull. He eventually won but it doesn’t bode well that it literally required a court case. As research into brain-machine interfaces continues to progress, prostheses will become harder to detach, even with chainsaws (which was the method of choice for parts jacking in Alita: Battle Angel by Alita’s boyfriend Hugo, a member of the Twilight Team-Jacob-let-me-take-off-my-t-shirt school of method acting).
Alita: Battle Angel is definitely worth seeing but it’s not an Avatar or Sin City sweep-you-off-your-feet event. The future is unlikely to have cyborgs that look like Alita or her overly mechanized enemies, but it will have cyborgs- injury and disease will see to that. Check out the May 2017 issue of Science Robotics and do a web search for Cybathlon, the real life fantastic Olympic games for cyborgs hosted by ETH Zurich, if you want to learn more about cyborg research.