A soldier wears a skullcap that stimulates his brain to make him learn skills faster, or reads his thoughts as a way to control a drone. Another is plugged into a Tron-like “active cyber defense system,” in which she mentally teams up with computer systems “to successfully multitask during complex military missions.”

The Pentagon is already researching these seemingly sci-fi concepts. The basics of brain-machine interfaces are being developed—just watch the videos of patients moving prosthetic limbs with their minds. The Defense Department is examining newly scientific tools, like genetic engineering, brain chemistry, and shrinking robotics, for even more dramatic enhancements.

But the real trick may not be granting superpowers, but rather making sure those effects are temporary.

Augmented Once, Augmented Forever?

The latest line augmentation research at DARPA, the Next-Generation Nonsurgical Neurotechnology (N3) program, is focused on one key part of augmenting soldiers: making sure the effects can be reversed.

Creating a seamless interface between human and machine invokes images of brain implants and cutting-edge prosthetics. The webpage of DARPA’s program notes that “the most effective, state-of-the-art neural interfaces require surgery to implant electrodes into the brain.” The N3 program, however, falls in line with the current trend in U.S. military research: Figuring out ways temporary, non-invasive ways to enhance soldiers.

The question of reversibility steers a lot of the debate over human augmentation. There are many ways to improve a person, from vaccines to corrective eye surgery. The question becomes when such efforts cross the line into “human enhancement.” Some researchers cite anything above a “baseline human” as augmentation. Laser surgery to correct vision is not enhancement, but a contact lens that enables 4x zooming would be.

“CAN CONSENT BE FULLY FREE FROM COERCION IN THE MILITARY?”

Things get thornier as scientists learn more about how to hack the human body and more enhancements become possible. This is most evident in genetic therapy when doctors add DNA containing a functional version of a lost or defective gene back into a cell. Medical researchers are getting good at this: Just this month, medical researchers for the first time cured an inherited disease that blinds its victims. “This restored vision to treated children and adults,” the news release claimed, “and in turn their success enabled the entire field of gene therapy for human disease.”

Just as prosthetics for amputees can lead to exoskeletons, gene-based cures can be adapted to become enhancements. If scientists can discover a way to circumvent a genetic limitation — say, adding cat DNA to human eyes cells to see better in the dark — such therapies can become tools in the enhancement chest. But gene therapy can be reversed by reinserting the original gene. At least, in theory.

Can a Soldier Consent?