DARPA's prosthetic limb research projects have yielded two advances that will surely be welcomed by the thousands of servicemen with amputated limbs. The new technologies allow limbs to be controlled more naturally, and even endow users with a rudimentary sense of touch.

The research being conducted is intended to create more reliable and long-term implants with which to control prostheses. Using a direct interface with nerves or the brain itself is something many researchers are interested in trying, but the Defense Advanced Research Projects Agency, part of the Department of Defense, is focusing more on everyday usability and longevity — two things that matter quite a bit to the devices' users.

With DARPA's Reliable Neural-Interface Technology (RE-NET) program, the agency "took on the mission of giving our wounded vets increased control of advanced prosthetics," wrote program manager Jack Judy in the blog post describing the research.

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The latest advances come from teams at the Rehabilitation Institute of Chicago and Case Western Reserve University, which are working independently but under the same DARPA directive.

In Chicago, they are working on "targeted muscle re-innervation," which allows the artificial limb to be controlled via the muscles still intact on the amputated limb. A bicep muscle, even if only partially retained after surgery or injury, could be tapped into and used as the trigger that makes the arm pull up — just as it would if the muscle were doing the job itself.

Meanwhile, the Case Western Reserve team has created a "flat interface nerve electrode" that sends signals the other way, allowing a very rudimentary sense of touch to be felt from sensors on the limb. While most prosthetic users must use their eyes to confirm that an object is gripped or in the right position, this tactile feedback, however slight, could make them able to operate the limb much more easily.

A user might be able to choose between a large and small object or take keys from their pocket without looking — a huge benefit. In the video above, a tester explains the feeling and how he would take the upgraded hand "in a heartbeat."

Swiss researchers are working with similar goals but a different approach; their implant can only be left in for a month at a time, while DARPA hopes theirs could be much more long-lived or even permanent.

For now the technologies are only in the lab, being tested in clinical trials and at military hospitals. The current DARPA-sponsored programs are expected to continue through 2016.

Devin Coldewey is a contributing writer for NBC News Digital. His personal website is coldewey.cc.