This Fourth of July weekend, Fred Downs and Artie McAuley will treasure independence in ways most of us take for granted, like grabbing a soda from a table or reaching into a pocket to answer a cellphone. And though football season has yet to start, for the first time in nearly a half-century Mr. McAuley will be able to raise both arms to celebrate a touchdown.

These simple, daily movements represent to them freedom in an intensely personal way: Both are Army veterans who lost part or all of an arm while in the service. Mr. Downs, a platoon leader in Vietnam, lost his left arm just above the elbow when he stepped on a land mine during a firefight in 1968. Mr. McAuley was assigned to an ordnance unit in upstate New York when a car accident cost him his left arm and part of the shoulder in 1969.

The men celebrated the start of the Independence Day weekend by becoming the first two recipients, according to the Department of Veterans Affairs, of astate-of-the-art robotic arm that uses computers, sensors and motors to give back to them the simple, but essential, functions they had lost in their youth. The arm — known as Life Under Kinetic Evolution or LUKE — is the result of an eight-year research project by the Department of Veterans Affairs, the Defense Advanced Research Projects Agency (known as Darpa) and private companies. Unlike current prosthetics available for upper limb amputees, the LUKE arm allows for smooth and simultaneous movement using motors at the shoulder, elbow, wrist and hand to flex and turn or lift and grip.

“This is a life-changer,” David J. Shulkin, the secretary of Veterans Affairs, said in a telephone interview Friday, shortly before a ceremony at the Manhattan V.A. hospital where the two veterans received their new arms. “Many people, including our first veterans being fitted today, are still using technology that was 40 years old, which is a hook mounted onto a piece of plastic. Now they can return to doing things like cooking, lifting up suitcases. It gives them a functionality they never had.”