Another challenge is the complexity of the Iron Man suit. To date, all BMI studies have used very simple tasks, and participants have focused on a single task at a time. This is “pretty artificial, since we rarely focus so much attention on simple motor tasks,” says Doug Weber of the University of Pittsburgh School of Physical Medicine and Rehabilitation, another leading scientist in the field. “No one has really studied how BMI performance changes when the user is performing other tasks in parallel. Multitasking would require at least a portion of the BMI control to be performed subconsciously.”
The bottom line is that, upon first jacking in to an Iron Man suit, any user would probably be able to learn how to do something straightforward like opening or closing one hand fairly quickly, within a few hours. How long to do something more complex like standing up and walking? Using benchmarks from neural rehabilitation after spinal cord injury or stroke, it is reasonable to estimate that about three months of training might provide the ability to stand up slowly and walk at about one-half the normal pace across a space of about 30 feet. That is pretty sobering when we think of what is shown in the comic
books and movies. Grabbing the suit, throwing it on, plugging it in, and running off would just not be possible.
Another consideration is the integrity of the nervous system/electrode connection. It is very difficult to interface technology with biology. Based on state-of-the-art animal experiments, it seems only about 50 percent of implanted electrodes can be usefully employed. Of those, there is a significant reduction in usefulness over time, largely due to a process known as encapsulation or reactive gliosis, a type of scarring of the nervous system associated with immune rejection.
Jennie Leach, of the University of Maryland, and colleagues describe the body’s reaction to an implanted neuroprosthetic as beginning with a rapid acute response characterized by inflammation and what is known as microglial activation. Microglia provide the protective immune response cells in the brain and spinal cord. They are a kind of macrophage, which means they attack and digest invaders and foreign objects in the nervous system and are the first and main form of active immune response in the brain and spinal cord. If an intruder cannot be digested, the microglia cover it up so that it can do no harm. This response becomes chronic, which results in the formation of a virtually impenetrable glial or fibrotic scar around the implant.
There is a long way to go to get to a stable, enduring implant like that needed for a full brain-machine interface in an Iron Man suit. And then, on top of that, to have the brain subjected to the kind of continual head trauma that Tony experiences—being slammed into cars, pummeled by Iron Monger, slammed into a bus, and hit by bomb blasts—isn’t really
a recipe for long-term success.
A Lifetime in Iron
Ultimately, for an iron man suit of armor to be useful, it must be based on the kind of brain-machine interface hinted at in the Extremis story line. It must respond without having to be consciously commanded. This would free up neurological resources needed for more challenging tasks and environments. The user must also be highly trained and in tip-top shape.
Iron Man project development would require substantial improvements from where we are today. The technology to develop a system with articulated armor currently exists. Tony Stark or anyone else who wants to follow in his footsteps would need about two years to adapt such technology to create the full body armor that we see in Iron Man. An additional four years would most likely be required to strengthen and lighten the suit and then incorporate it all into a fully mobile passive system. Such a system would move like armor reminiscent of that of medieval knights but much more freely.
Next, providing the extras that Iron Man needs for his life of crime fighting would require motorizing and energizing the armor. A prototype would take another four years. Even when this improved armor was complete, its user would encounter a major problem: The current standard for this kind of approach in industry is to use hydraulic actuators (think of a forklift), which are extremely heavy. So Tony would have to make the armor even lighter and the motors much smaller and more efficient. A key focus for Tony in the next 10 years of developing his suit would be to miniaturize the motors that control the movement of the fully powered armor.
The next steps would each involve a slightly more invasive integration between the suit and the nervous system. The first would be to get stable motor control by using Tony’s own nerve signals to trigger the movement of the suit. Existing neuroprosthetics aren’t adequate. To bring it up to Iron Man capabilities would require improved processing of nerve signals, which would take about three or four years.
Then Tony would have to get around the delays and control problems that go along with using measurement of muscle activity. Tony would instead use direct brain commands to move the suit, requiring a suitable brain-machine interface. The basic technology already exists, but it typically involves surface electrodes on the scalp. These provide only limited two-dimensional (for example, up and down, side to side) movement control; they could be used for controlling only a paper-thin Iron Man moving across the pages of a comic book.
To function in three dimensions, Tony would need to spend another five years improving the understanding of brain output as a control signal. He would then most likely try to use the signal with the highest content: direct, single-cell neuronal recordings. A basic version of this technology is available now, but it has been restricted mostly to controlling simple arm movements in monkey studies. During those five years, along with an improved knowledge of brain output from neuronal recordings, the safety of recording from the human brain for prolonged periods would need to be improved.
At this point, Iron Man would still be able to execute only rudimentary walking, lifting, and striking movements and only with Tony’s paying strict attention and concentrating fully on the task at hand. More work remains.
Tony continues to toil just about every night. In the fourth decade of Iron Man R & D, we move into unknown territory. A highly functional suit would require some kind of direct meshing between Tony’s entire nervous system, both sensory and motor, and the Iron Man armor. This could be achieved only through some form of nanotechnology. This technology does not yet exist, not even a little bit, although the good news is that nanotech research, particularly for biomedical applications, is a rapidly expanding field.
An additional hiccup is how to deal with immune system rejection of any such interface and controlling the inflammatory response so that the interface could be maintained over time. It’s not even possible to identify a timeline for this stage.
Finally, Tony would need physical training to become fully comfortable and competent with the Iron Man suit. This adds another 5 to 7 years and gives a total projected timeline for inventing Iron Man and putting him into service of almost 40 years. If my math is correct, Tony will be in his sixties by the time he masters being Iron Man. Inventing, developing, and bringing Iron Man to reality would truly be a life’s work. But what a life!
Excerpted from Inventing Iron Man: The Possibility of a Human Machine, by E. Paul Zehr, The Johns Hopkins University Press. Copyright 2011 by E. Paul Zehr. Reprinted by permission of the publisher and the author.