NASA’s Jet Propulsion Laboratory is pushing the boundaries of structural design and advanced manufacturing with its integration of 3D printed crushable lattices into the Mars Sample Return mission. Spearheaded by mechanical engineer Ryan Watkins, the initiative brings together cutting-edge simulation tools, process-controlled additive manufacturing, and a broader lesson of how understanding of institutional culture can achieve a rare feat: moving a novel technology from research prototype to mission-critical hardware.
Key Insights from Ryan Watkins’ NASA – Built to Break, Designed to Protect: Developing and Implementing 3D Printed Crushable Lattices
The Hardest Part Isn’t Technical: It’s Cultural: The real challenge was not designing or manufacturing the lattices, it was getting the technology accepted for use in a flagship NASA mission.
Trust and Embedded Experience Matter: Watkins spent his first five years on JPL’s engineering side, building trust with mission teams.
Process Control and Agility Won the Day: What persuaded the review board wasn’t theoretical performance; it was tight process control and design agility.
Simulation and Design Software: UnitcellHub: Enabled rapid narrowing of the design space: selected and tested only two lattice designs to meet all structural requirements
A Call to Go Beyond Demos: Watkins urged the AM community to stop showcasing lattices as visual proofs-of-concept and instead pursue meaningful applications.
NASA turns to crushable 3D lattices for safe Mars sample return
Additive manufacturing is tackling one of the most critical technical challenges in planetary exploration: how to ensure that Mars samples survive a high-speed return to Earth. “The final stage of the Mars Sample Return mission isn’t a parachute landing. This is terminal velocity impact, about 110 miles per hour,” Watkins explained, pointing to high-speed testing at JPL’s four-story drop tower.
NASA’s Mars Sample Return (MSR) mission aims to retrieve geological samples currently being collected by the Perseverance rover, which landed on the Martian surface in 2021. Those samples from the Jezero Crater are expected to be collected, sealed, and launched into Martian orbit before being returned to Earth. But without propulsion or aerodynamic braking, the return capsule will strike Earth’s surface at speed, presenting a daunting materials challenge.
Sample return has been a three-decade goal of U.S. space agency scientists now working with counterparts at the European Space Agency (ESA). To solve this, Watkins’ team is using 3D printed crushable lattices, a class of engineered structures designed to deform in a controlled way and absorb impact energy. The approach reflects a growing AM use at JPL, where additive manufacturing is no longer confined to research prototypes or minor components. “We’re not just printing parts: we’re designing entire systems around the capabilities of these materials,” he said.
JPL’s additive journey spans decades, with its first space-bound printed part, a nylon SLA component, dating to the late 1990s. After a lull, activity resumed in earnest around 2014 with polymer printers, followed by the first metal 3D printed parts integrated into space missions. Eleven metal parts, both titanium and Inconel, are flying on the Perseverance rover.
By 2021, JPL had implemented NASA Standard 6030 for additive manufacturing and fully qualified its primary metal AM systems. These were used to fabricate an aluminum bracket now en route to Jupiter’s moon Europa aboard the SPHEREx mission. That spacecraft also includes over 50 3D printed plastic components.
Watkins emphasized that the focus is no longer simply on qualifying parts for space. The aim is to integrate new materials, such as gradient alloys or shape-memory metals, with design philosophies like topology optimization. “It’s about enabling entirely new architectures,” he said. “We’re pushing toward missions where additive isn’t just part of the payload, it’s part of the mission concept from the outset.”
In the case of the Mars Sample Return capsule, the 3D printed lattice is both a novel and pragmatic solution. Traditional impact attenuation systems, such as crushable foams or mechanical dampers, don’t provide the mass-efficiency, customizability, or integration flexibility that a lattice offers. Using custom advanced simulation tools, Watkins’ team has been able to iterate quickly, optimizing the geometry for a precise deformation response under Earth re-entry conditions.
These lattices, made from high-strength metals, are designed to collapse on impact, absorbing kinetic energy and protecting the sample container from excessive forces. The underlying software used to design the structures, UnitcellHub, has recently won NASA’s Software of the Year award, enabling engineers to digitally model and test lattice configurations before fabrication.
“There is a high probability that a lot of our future missions are going to have more than a few metal 3D printed parts on them,” he said. “We’re building the tools to make that shift scalable, certifiable, and mission-critical.”
JPL turns to software-driven 3D lattices for Martian sample return
“Engineers love crushable lattices because you can get very reliable responses that ensure you protect the thing you’re trying to protect,” said Watkins. At the heart of the design is the unit cell, the smallest repeating structure within a lattice. The UnitcellHub software includes a simulation engine, a database of pre-computed lattice properties, and a user interface. The tool allows engineers to input mechanical requirements and quickly explore tens of thousands of unit cell configurations, along with their properties, such as stiffness, yield strength, thermal performance, and relative density.
“Instead of randomly searching the literature and printing hundreds of coupons, I used this tool to select two lattices, printed them, did two tests, and was about 90% of the way there,” Watkins said. He ultimately selected a diamond-shaped unit cell due to its ability to absorb impact energy while avoiding global instabilities such as shear banding, structural failures that can cause unpredictable force spikes during compression.
The design challenge hinges on managing two primary variables: relative density (the proportion of solid material to empty space) and length scale separation (the ratio between the unit cell size and the overall structure). Optimal lattices must be sparse enough to compress over a long stroke, but small enough in feature size to distribute load evenly and predictably.
This requirement pushes the limits of metal 3D printing. Standard direct metal laser sintering (DMLS) systems struggle to reliably print features below 300 microns without introducing surface roughness and internal voids. Watkins’ team initially explored tuning printer parameters but ultimately adopted post-processing techniques, specifically chemical etching, to achieve ultra-low relative densities and improve surface finish without compromising material integrity.
“Fixing material properties is much harder than dealing with surface roughness,” Watkins noted. The chemical process allowed the team to etch ligaments down to sub-100-micron thicknesses, enabling length scale separations sufficient for high-performance energy absorption.
Load testing confirmed the benefits. When compared to commercial off-the-shelf aluminum honeycomb panels, the 3D printed lattices demonstrated nearly identical stress–strain behaviour, with smooth plateau regions and ductile collapse mechanisms. “There’s no premature fracture,” Watkins said. “All of this is highly ductile failure, which is exactly what you want.”
From a design perspective, the UnitcellHub software enabled rapid iteration through a vast parameter space. Its simulation engine uses finite element analysis to compute key structural properties, but even with optimised meshing, full-scale models require significant computational resources. A gyroid-based lattice with 20,000 unit cells—comparable to the Mars Sample Return structure—would exceed two billion finite elements.
To manage this complexity, the platform uses surrogate modelling, trained on a database of over 15,000 lattice point designs, to predict behaviour in real time and guide selection. Engineers can explore trade-offs visually, using Ashby-style plots or multi-objective performance maps, and directly adjust geometric parameters through an interface that links to both precomputed data and predictive models.
For the Mars mission, the team needed a structure that would yield just below the breaking strength of the Martian sample container, approximately 2.5 MPa, and compress over a sufficient stroke to absorb the kinetic energy of impact. Of the candidate lattices in the software, only three met both criteria. After testing two of them, the diamond lattice was selected for its flat stress plateau and stable deformation.
JPL’s experience illustrates how additive manufacturing, when tightly integrated with simulation, can now offer not just form freedom but design certainty. “We’re building tools that enable us to treat lattices as first-class structural elements,” Watkins said. “This is about giving engineers the ability to predict and control the mechanical response of these complex materials – not just print them.”
JPL overcomes structural and cultural barriers to bring 3D printed lattices to Mars mission
The practical realities of advancing from experimental design to implementation formed an insightful part of Watkins’ presentation. “Everything I talked about is really just one through five,” he said, referring to NASA’s Technology Readiness Level (TRL) framework. “The real challenge is getting past the TRL 5–6 transition, that valley of death where most technologies die.”
NASA’s nine-step TRL system measures a technology’s maturity, with TRL 1 representing early-stage research and TRL 9 indicating flight-proven hardware. The leap from proof-of-concept to flight integration is fraught with barriers. In this case, the technical feasibility of the crushable lattice structures had already been demonstrated. The larger challenge, Watkins said, lay in convincing implementation teams to accept them.
“The hard problems are the non-technical ones. Culture, silos, ease of use; these are the reasons technologies stall,” Watkins noted. He pointed to the longstanding disconnect between research teams and engineering implementers. “Researchers think they know what engineers want, and engineers don’t trust what researchers develop.”
What made the difference, according to Watkins, was his prior experience on the engineering side of JPL. “I knew the people working on the sample return mission. They trusted me. I knew what they actually cared about: not the theoretical advantages, but the real-world implications,” he said.
The key breakthrough was not just the energy absorption potential of lattices or their geometry-specific tuning. It was the tight process control enabled by in-house metal 3D printing using JPL’s fully qualified laser powder bed fusion machines. “What sealed the deal in our first design review wasn’t the mechanical performance. It was our ability to maintain process control and change materials quickly as the mission evolved,” Watkins said. “Agility matters more than theoretical superiority.”
NASA has now cleared its Preliminary Design Review (PDR) for the Mars Sample Return mission and is preparing for the Critical Design Review (CDR), the final engineering checkpoint before manufacturing begins. While technical development continues, Watkins said the remaining work is focused on engineering execution: finalising analysis workflows, controls, and inspection protocols.
The selected lattice structure will be used to shield geological samples during high-velocity Earth impact, eliminating the need for propulsion or parachute-based landing systems.
Watkins ended with a call to the broader additive manufacturing community. “We see lattice structures on showroom floors all the time. But too often we’re demonstrating printing technology, not the engineering value of lattices,” he said. “I want to protect samples coming back from Mars. What do you want to do with lattices?”
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Featured image shows NASA JPL’s Ryan Watkins at the 2025 AMUG Conference. Photo by Michael Petch.
