Updated: 5/22/2026
This week at the International Friction Welding Conference 2026, retired Bond Technologies president and ongoing consultant Dave Hofferbert presented presented research that marks a genuine first: the first solid-state weld ever performed in vacuum.
The presentation examined a practical question: how do you build large, durable structures on the Moon without minimal human intervention to manage the assembly?
A Different Set of Requirements
A sustained human presence on the Moon requires infrastructure, and power is one of the first problems to solve. Solar energy is available, but the uneven lunar terrain and long lunar nights limit what fixed arrays can reliably provide. One concept under evaluation is tall solar tower structures — approximately 50 meters in height — designed to extend access to sunlight and support surface operations.
In a project funded by NASA, Bond Technologies and EWI are evaluating how those structures could be manufactured and assembled using automated processes built around Refill Friction Stir Spot Welding (RFSSW). The presentation at IFWC focused on the process and environmental challenges associated with that work — specifically, how friction-based joining performs under vacuum conditions and severe thermal extremes that simulate aspects of the lunar surface.
Why RFSSW
RFSSW is a solid-state joining process used primarily for aluminum structures. Rather than relying on traditional fasteners or melting the base material, RFSSW uses frictional heat and plastic deformation to create a localized spot weld. For an automated assembly system operating without a crew, that matters: fewer parts to manage, fewer handling steps, and less complexity in an environment where every variable counts.
Those advantages are already well understood in manufacturing on Earth — the harder question Bond and EWI set out to answer is whether they hold in an environment as extreme as the lunar surface.
Testing in a Simulated Lunar Environment
The work centered on a straightforward problem: can refill friction stir spot welds actually be produced under these extreme conditions? Testing at Michigan Technological University’s Planetary Surface Technology Development Lab demonstrated that yes, they can — in high vacuum and across temperatures ranging from approximately -196°C to +100°C. The work also evaluated tooling behavior, process parameters, and joint performance across multiple environmental setups.
Bond’s RS2 RFSSW head was modified to operate under the test conditions, with updates to support performance across the full temperature range and within the environmental testing chamber.
The results don’t establish readiness for deployment, but they do demonstrate that the process works under conditions that begin to approximate the lunar surface — which was the objective of this phase of work.
Toward Automated Assembly
The broader concept under development is a fully automated system for assembling tall aluminum truss towers on the Moon. The current design targets a tower approximately 50 meters tall with a structural payload capacity of around 250 kilograms (in moon weight, or approximately 1500 kg earth weight), incorporating automated material handling, robotic positioning, and joining provided by RFSSW. Bond’s role is focused on the joining process and how it integrates into that larger system.
Beyond Towers
The solar tower is a concrete near-term application, but the potential reach goes well beyond it. If aluminum can be extracted from lunar regolith — and several groups are actively working on exactly that — then having reliable joining and forming technologies available on the Moon becomes part of a much larger manufacturing picture.
According to Hofferbert, NASA has been pushing hard on In Situ Resource Utilization (ISRU) — the goal of building and operating on the Moon using lunar resources rather than shipping everything from Earth. His presentation outlines how friction-based processes for forming and joining aluminum could eventually contribute to that chain, opening the door to applications well beyond solar towers.
A Measured Step Forward
There is still significant work ahead. Questions surrounding long-term equipment durability, thermal management, radiation exposure, and lunar dust remain open. The research Hofferbert presents this week makes no claim of full readiness for space deployment — what it does show is that the process functions under conditions that resemble the lunar environment, and that is where this work stands today.
Bond Technologies is proud to be part of work that is pushing friction welding and processing technologies into territory that, until recently, existed only in theory.
A Note on a Well-Deserved Honor
Also at IFWC 2026, Hofferbert was presented with the TWI Wayne Thomas Innovation Award — by Wayne Thomas himself. Thomas invented Friction Stir Welding at TWI in 1991, a development that fundamentally changed the way aluminum structures are joined and opened the door to the technology Bond has spent decades advancing. Receiving that recognition from the man who started it all makes the moment particularly meaningful. Congratulations, Dave.
Presentation Details
Dave Hofferbert presented:
Refill Friction Stir Spot Welding in a Lunar Environment
Date: May 20, 2026
Time: 14:10 BST
Location: Lecture Room 1, IFWC 2026 – Cambridge, England
