VELUM: Ultra-Lightweight Composite Membranes for Minimal-Leakage Aerial Vehicles

Published in Aerospace Science and Technology (2026).

A New Membrane Architecture for the Next Generation of Airships

Airships and aerostats are experiencing a renaissance. Driven by the need for persistent, energy-efficient aerial platforms — from surveillance to cargo transport — interest in lighter-than-air vehicles has grown significantly in recent years. At the heart of any aerostat is its envelope membrane: the structure that contains the lifting gas, bears the aerodynamic loads, and must do all of this at the lowest possible mass.

Our latest paper introduces VELUM — a novel composite membrane architecture specifically engineered for minimal gas leakage while maintaining ultra-low areal mass. This work complements the lab’s ongoing research on lightweight rigid structures for indoor aerostats (see the 3D Printed Aerostats project), now extending to the flexible envelope itself.

The Problem: Leakage vs. Mass Trade-off

Helium and hydrogen — the gases used in lighter-than-air vehicles — permeate slowly through any membrane. For small indoor aerostats, even slow permeation means frequent refills and limited mission duration. The conventional solution is to increase membrane thickness or add barrier coatings, but both approaches add mass, directly reducing the useful payload.

The VELUM architecture addresses this leakage-mass trade-off through a structured composite approach: combining carefully selected barrier films with structural textile reinforcements in a geometry optimized for permeation resistance without thickness penalty.

Key Contributions

• Novel membrane architecture that decouples gas barrier performance from structural stiffness requirements
• Experimental characterization of helium permeation, tensile properties, and areal density for the proposed system
• Comparison with state-of-the-art commercial aerostat envelope materials
• Design guidelines for membrane selection and layup in ultra-lightweight airship applications

What This Means for Airship Design

The VELUM results demonstrate that it is possible to achieve competitive gas barrier performance at lower areal mass compared to commercial alternatives. This creates new design space for mission planners: longer autonomous missions, larger payload fractions, or simply smaller and more agile vehicles for the same mission profile.

This work is a direct output of the Flying Whales collaboration and positions ilylabs at the intersection of composite manufacturing and lighter-than-air vehicle design.