The US Army's Vision of Soldiers in Exoskeletons Lives On

After decades of research and development, the United States Army is taking yet another run at developing a powered exoskeleton to help soldiers carry heavy loads on the battlefield—but don’t expect a futuristic suit of combat armor straight out of Starship Troopers or Iron Man anytime soon.

Soldiers assigned to the Army’s 1-78 Field Artillery Battalion training unit at Fort Sill, Oklahoma, recently completed a three-day “proof of concept” evaluation of several off-the-shelf “exoskeleton suits” in late September and early October, officials confirmed to WIRED. The evaluation was overseen by the service’s Combat Capabilities Development Command (DEVCOM), the organization responsible for developing new technology for soldiers.

Official photos from the evaluation published to social media showed Advanced Individual Training students hauling artillery shells to and from a M109 Paladin self-propelled howitzer and M777-towed howitzer with telltale black exoskeleton harnesses contrasted against their camouflage uniforms, part of a field exercise undertaken “to assess the potential of human augmentation, improve soldier performance, and determine if these exoskeletons meet the demands of our warfighters,” as the service put it.

While a DEVCOM spokesperson declined to identify which commercially produced systems were evaluated by soldiers, the Army announced its intent in August to award a contract to exoskeleton maker SUITX to “give users experience of advanced soldier augmentation technologies,” according to a government notice. “This exoskeleton will serve as a critical tool for evaluating the potential benefits of robotic assistance in increasing soldier endurance, strength, and overall operational effectiveness.”

Increased strength and endurance are an alluring duo for an American fighting force used to hauling close to 140 pounds into combat, and the prospect of a sophisticated combat suit that delivers both to soldiers even more so. But DEVCOM officials strongly emphasized that, despite this recent testing, the US military has yet to even determine how to actually apply a powered exoskeleton in a military context, let alone outfit soldiers in an “Iron Man suit” the likes of which the Army has bragged about in years past. Indeed, service officials tell WIRED that an official requirement document—a formal outline of a potential program’s technical and logical preconditions—for the adoption and fielding of exoskeletons does not currently exist, despite the fact that officials previously stated back in 2020 that Army Futures Command, DEVCOM’s superior organization, was closing in on one.

“As of today, the Army has not determined what the primary purpose of a ‘military exoskeleton’ is,” says David Accetta, a DEVCOM spokesperson.

That the Army is taking another crack at a powered exoskeleton should come as no surprise. The US military has been pursuing such technology for potential tactical applications for decades, since around the same time that science fiction author Robert Heinlein introduced the world to his vision of a “mobile infantry” flitting across future battlefields clad in advanced robotic armor in his beloved 1959 military science fiction classic Starship Troopers. Where Heinlein imagined future soldiers operating a mechanized battlesuit reminiscent of “a big steel gorilla, armed with gorilla-sized weapons,” the ostensible advantage of powered armor wasn’t just its added strength and durability, but the fact that “you don’t have to control the suit; you just wear it, like your clothes, like skin.” No fancy control interface, no complicated training: Soldiers would ostensibly step into a notional apparatus and be ready to “fight tonight,” as US military planners are fond of saying.

With an eye to future conflicts on an atomic battlefield, the Cold War-era US Defense Department clearly drew at least some inspiration from Starship Troopers. One year after Heinlein’s novel published, the Army went on the hunt for a “power-operated mechanical suit or skeleton that would transform the ordinary GI into a Superman,” according to a 1960 issue of the service’s Army Research & Development magazine, with future “servo-soldiers” hauling munitions and other heavy equipment “beyond the strength of a dozen men.” The servo-soldier “will wear a special suit which will have its own engine, enabling him to run faster, stop quicker, and lift bigger loads than ordinary mortals,” as Armor magazine put it in 1961 when the Pentagon officially solicited the defense industry for potential exoskeleton solutions. “What is more, he will be immune to germ warfare, poison gas, and the heat and radiation from nuclear blasts.”

In the following decades, the Pentagon took several stabs at making the servo-soldier a reality. In the 1960s, Cornell University engineer Neil Mizen’s “Man Amplifier,” funded by an Office of Naval Research grant, offered service members a patchwork of robotic components intended “to help sailors manhandle torpedoes, bombs, and machinery in the cramped quarters aboard ships and submarines,” as Popular Science described it in a November 1965 issue. In the later part of the decade, General Electric debuted its “Hardiman” exoskeleton, developed under a dual Army-Navy effort, a colossal, bulky apparatus that more closely resembled the P-5000 Powered Work Loader from the 1986 movie Aliens than a sleek battlesuit like Iron Man’s armor. In the 1980s, Los Alamos National Laboratory Advanced Weapons Technology Group engineer Jeffery Moore offered the Pentagon its most futuristic vision of a powered exoskeleton yet with his proposed “Pitman” combat suit, a vision of robot armor so advanced it remained a mere concept without ever producing a prototype. Every decade, the Pentagon appears to stand up and quickly wind down an exoskeleton project without ever producing a feasible prototype.

While the Defense Advanced Research Projects Agency (Darpa) oversaw incremental advances in US military exoskeleton research in the early 2000s, the most recent concerted attempt at a suit of powered armor came in the last decade in the form of US Special Operations Command’s Tactical Assault Light Operator Suit (TALOS). Inspired by the death of a Navy SEAL during a hostage rescue effort in Afghanistan, TALOS sought to cloak elite US special operations forces in additional layers of ballistic armor, sensors, and an exoskeleton to boost their survivability and situational awareness to near-superhuman levels. But while the TALOS program did yield several novel technologies (a lower body exoskeleton among them), the effort was canceled in 2019 after just five years of research and development, felled by “complex subsystem interdependencies” between its various elements that failed to coalesce into a unified and intuitive suit that operators could “just wear,” as Heinlein envisioned decades earlier. (SOCOM would pivot to its “hyper enabled operator” concept, which focuses on “cognitive overmatch” rather than physical augmentation to give American commandos an edge on the battlefield.)

Wary of the technological complexity required to develop mechanized armor for infantry troops, the Pentagon has spent the better part of the last two decades, with the exception of SOCOM’s TALOS effort, scaling back its exoskeleton ambitions to better match the original duties of the servo-soldier: hauling munitions and other heavy equipment. The Army’s Robotics and Autonomous Systems strategy released in March 2017, for example, stated that the service would pursue exoskeleton research primarily “to lighten the soldier load in the future” as a near-term priority as the Pentagon began its pivot from counter-insurgency operations in the Middle East to “great power competition” with technologically-advanced “near-peer” adversaries like Russia and China. The following October, in a letter to senior officials laying out the Army’s core modernization priorities for the coming decades, General Mark Milley, then the Army chief of staff and later chairman of the Joint Chiefs of Staff, declared that the service would eventually field “load-bearing exoskeletons” as part of a renewed emphasis on “soldier lethality” (the next year, Milley directed DEVCOM to undertake “a detailed engineering analysis of existing and emerging exoskeleton products” for their potential military applications).

This newfound push appears to have yielded several fresh experiments with exoskeleton technology in recent years. In 2018, Lockheed Martin was awarded a $6.9 million contract to “enhance” its ONYX exosuit for future Army demonstrations (Accetta, the DEVCOM spokesman, tells WIRED that initiative was ended due to a “number of technical issues” and lack of funding). Similarly, the service has been testing the Dephy ExoBoot for at least the last several years. In August 2022, the Army unveiled an (unpowered) exoskeleton dubbed the Soldier Assistive Bionic Exosuit for Resupply (SABER) to reduce lower back pain and physical stress among service members in the field; according to a 2023 study, 90 percent of soldiers who used the exosuit during field artillery training exercises reported an increased ability to perform their assigned tasks. And the Army isn’t the only branch exploring exoskeletons: Later in 2022, the Air Force announced that the service was testing its own pneumatically powered exosuit developed by ROAM Robotics to help aerial porters load up cargo aircraft like the C-17 Globemaster III.

The Fort Sill exoskeleton trial isn’t just the latest installment in a seven-decade push to meld man and machine; it’s also representative of the service’s cautious, restrained approach to the technology. Although US military planners may have long aspired to build an army of those so-called servo soldiers to dominate the future battlefield, current exoskeleton research efforts appear laser focused on more modest and potentially attainable applications like logistics and resupply rather than combat engagements. Slowly but surely, the Pentagon is carefully examining whether a robotic assist will help service members carry more for longer downrange.

But the Pentagon doesn’t appear to have totally given up on its dream of a powered exoskeleton as the basis for an armored battlesuit just yet. The 2017 Army RAS strategy, despite its emphasis on lightening soldier loads, also posited the long-term goal of building a “warrior suit” with “integrated displays that aggregates a common operating picture, provides intelligence updates, and integrates indirect and direct fire weapons systems”—capabilities not unlike those imagined with a notional Starship Troopers mobile infantry or Iron Man suit-clad operator and explored with the TALOS initiative. As of a few years ago, at least one Army official was still talking about such a suit as a long-term effort that could potentially become a reality sometime in the 2040s.

Today, however, that idea appears to be in hibernation, if not fully dead. When asked about the “warrior suit” effort, DEVCOM officials threw cold water on the entire concept as “the professional vision of one person” and “not to be considered (even at the time) as an official Army position,” despite its explicit mention in the 2017 RAS document.

“The ‘warrior suit’ never existed as such, it was never considered a ‘warrior suit’—at least not by the Army—but a proof of concept, meaning, ‘Would something like this help manage load while on the move?’’ Accetta says. “The number of technical, integration, design, power, ergonomic, and so on concerns were not trivial.”

“The project is not abandoned, it’s simply inactive,” he adds. “And if it ever were to become active, we doubt highly it would be called a ‘warrior suit.’”