Will There Be 3D Printed Autophage Missiles?

First publicly unveiled at the University of Glasgow a year ago, advancements in “autophage” rocket engines promise significant efficiency gains. These polymer-based rocket motors are designed to consume themselves in a predetermined sequence. By optimizing their structures, the engines can use melted polymer components—formerly structural parts of the engine—to augment liquid propellant as the rocket progresses.

The advantages are clear: rockets could be smaller, require less material, and travel further. With reduced lift needed for propulsion, the overall efficiency and performance of such systems could see substantial improvements.

3D Printed Solid Fuel Rocket Engines

Amid the need for new design directions and the depletion of existing stockpiles, the U.S. is increasingly turning to solid-fuel rocket engines to augment current capabilities and power a new generation of rockets. Xair Robotics pioneered the 3D printing of solid-fuel rocket engines as early as 2015. Another startup, X-Bow, established in 2016, collaborated with NASA and other entities to produce low-cost engines at scale. Firehawk Aerospace has taken a different approach, leveraging its proprietary form of material extrusion to manufacture hybrid rocket engines. Among these players, Ursa Major appears to have emerged as the biggest winner thus far, securing a significant Navy contract to develop solid rocket engines.

The Air Force Research Laboratory and other organizations have long pursued the concept of a “rocket factory in a box.” While this initiative partly addresses the need to replenish arsenals and improve missile manufacturing efficiency, its broader significance lies in the potential for localized missile production. Although this technology has clear applications for rockets designed to launch satellites into space, the bigger and more important picture is missiles.

Missile Gap

The U.S. simply cannot produce enough missiles to strike a significant number of targets. In a war with China—emphatically not a short conflict designed to make optimal use of U.S. strengths but a prolonged engagement—the U.S. would lose. The sheer number of targets would overwhelm its capacity. Drone proliferation has exacerbated this problem a thousandfold. Whether in handheld missiles like the Javelin, anti-aircraft batteries, or cruise missiles, the U.S. is falling short.

3D printing could enable efficient missile production at varying scales and volumes. It could replace scarce materials with alternatives and allow for on-site manufacturing at major bases. One size fits all!

3D Printed Missiles

Separately from and overlapping with solid rocket motor development, companies such as Raytheon have been exploring the 3D printing of entire missiles—electronics, housing, struts, the warhead, sensors, engine, control surfaces, radar components, RF components, hydraulics, servos, actuators, main motors, smaller motors for fins and seekers, gimbals, wiring, shock insulation—essentially everything. While this approach enhances production speed and efficiency, it also offers significant additional advantages.

Parts consolidation and mass savings are among the most obvious benefits. Many components can also serve dual purposes—for example, a battery housing could function as the battery itself. Conformal parts made possible through 3D printing can drastically reduce size, while the technology also allows for specialized enhancements, such as more efficient hydraulics or improved warheads. The business case for 3D printing missiles is exceptionally strong, rivaling that of implants.

3D Printing Advantages

Stacking the advantages for just one component, such as a servo valve for missile fin control, reveals the revolutionary potential of 3D printing in missile design:

• Performance Enhancements:
  • More efficient.
  • Faster response.
  • Reduced mass.
  • Better flow.
  • Higher precision.
  • Higher reliability.
  • Tailored specifically to this missile’s needs rather than a generic or cross-application design.
• Production and Integration Benefits:
  • Conformal or partially conformal design to fit precisely within the missile’s structure.
  • On-demand production at a specific location.
  • Higher production volumes to meet demand.
  • Drastically faster lead times compared to casting or forging.
  • Improved buy-to-fly ratio, minimizing wasted material.
• Economic and Labor Advantages:
  • Reduced reliance on manual labor, both in production and final assembly.
  • Smaller production footprint.
  • Reduced capital expenditure on tooling and spare parts.
• Design Synergies:
  • Integrated functionality (e.g., housing doubling as a battery).
  • Lower overall weight by further reducing part count as a cascading effect.

These benefits don’t stop at the servo valve. They extend to RF components, actuators, wiring, and beyond. This level of innovation heralds a revolution in missile design, enabling unprecedented performance, efficiency, and adaptability.

Autophage

Imagine leveraging these advantages across many parts of the missile—perhaps even transforming certain components or nearly the entire missile into an autophage system. Such a system could perform all the previously described functions while also enabling elements like a valve to serve as fuel. The implications are remarkable. Beyond performance enhancements, this approach ensures that the missile would leave no trace behind for adversaries to recover. Even in the event of a malfunction or falling short, much of the sensitive, cutting-edge design would already be consumed.

However, achieving complete combustion is challenging with solid materials like Inconel or titanium. So, what if the entire rocket were made from plastic—ABS, for example? This material choice would not only reduce weight but also simplify the problem significantly. Of course, this innovation raises the question of whether it could inadvertently accelerate proliferation by enabling missile components to be produced using desktop 3D printers.