This article is based on an official press release from TOPPAN Holdings and SoftBank Corp.

SoftBank and TOPPAN Unveil Ultra-Lightweight Wing Skin for Stratospheric HAPS Aircraft

In a significant step toward the realization of 6G “flying base stations,” SoftBank Corp. and TOPPAN Holdings Inc. have announced the joint development of an ultra-lightweight, highly durable wing skin. According to a joint press release issued on April 27, 2026, this new material is specifically engineered for solar-powered High-Altitude Platform Station (HAPS) aircraft.

HAPS vehicles are uncrewed aircraft designed to operate in the stratosphere at an altitude of approximately 20 kilometers. By functioning as airborne telecommunications towers, they offer broader geographic coverage than traditional ground-based cell sites and deliver higher-volume, lower-latency connectivity than satellite networks. We anticipate these platforms will become crucial for disaster recovery and bridging the digital divide in remote regions.

The newly developed wing skin solves a major physical bottleneck in sustained stratospheric flight, combining extreme weather resistance with the strict weight requirements necessary for solar-powered aviation.

Engineering for the Edge of Space

The Stratospheric Challenge

Operating at 20 kilometers above sea level exposes aircraft to environmental extremes that rapidly degrade conventional aerospace materials. According to the project’s technical data, temperatures in the stratosphere can plummet to between -50°C and -95°C, while surfaces exposed to direct sunlight can heat up to 100°C.

Furthermore, the stratosphere features intense shortwave deep ultraviolet (UV-C) radiation and high-concentration ozone levels ranging from 10 to 20 parts per million. The press release notes that these harsh conditions typically destroy the structural integrity of standard all-purpose films, making long-endurance flights nearly impossible without specialized shielding.

Adapting Packaging Technology for Aerospace

To overcome these environmental hurdles, TOPPAN utilized its proprietary “converting technology”, a sophisticated process originally developed for consumer packaging films that involves precise printing and lamination.

“By layering proprietary materials over an impact-resistant base resin designed for extreme cold, they created a skin that resists tearing and degradation,” the project documentation states.

Crucially, the joint announcement confirms that despite the added durability and multi-layered protection, the new skin weighs the same as or less than conventional aircraft skins. This weight efficiency is a mandatory requirement for HAPS aircraft, which rely entirely on solar power and must remain as light as possible to maintain sustained flight.

A New Standard in Material Testing

The partnership between the telecom giant and the materials manufacturers also yielded a breakthrough in aerospace testing methodologies. Historically, testing materials for stratospheric conditions on the ground has been difficult due to the complex interplay of extreme cold, radiation, and atmospheric gases.

According to the release, TOPPAN engineered a novel testing infrastructure capable of simulating the stratosphere’s unique environment. This new facility simultaneously exposes materials to cryogenic temperatures, shortwave UV rays, and high ozone concentrations. This allows engineers to accurately observe and measure stratospheric degradation mechanisms without needing to launch test flights.

SoftBank played a critical role in this phase by providing real-world stratospheric data gathered from its previous HAPS flight operations. SoftBank supplied exact temperature profiles and UV-C exposure metrics, while also defining the strict weight and aerodynamic performance requirements for the final material.

Commercialization Timeline and Strategic Goals

The companies have outlined a clear roadmap for bringing this technology to market. Throughout fiscal 2027 (ending March 2028), SoftBank and TOPPAN will continue their research to make the current skin material even lighter and stronger. By fiscal 2028, the partners target the establishment of mass-production technology to ensure reliable quality and sufficient supply.

Official commercial services utilizing this new wing skin on SoftBank’s heavier-than-air (HTA) HAPS aircraft are slated to launch in 2029. Additionally, both companies stated they are exploring broader applications for this highly durable material in other industries that require extreme weather resistance.

AirPro News analysis

We view this partnership as a critical indicator of two major industry trends. First, it highlights SoftBank’s comprehensive, dual-track approach to stratospheric infrastructure. While the telecom company invested $15 million in U.S.-based aerospace firm Sceye in June 2025 to deploy lighter-than-air (LTA) airships for pre-commercial services in Japan starting in 2026, this TOPPAN collaboration secures the supply chain for its heavier-than-air (HTA) fixed-wing aircraft targeted for 2029. SoftBank is effectively hedging its bets across different aerodynamic platforms to ensure dominance in the emerging 6G landscape.

Second, this development underscores TOPPAN’s strategic corporate pivot. Historically recognized as a traditional printing and packaging giant, TOPPAN is successfully leveraging its legacy converting and lamination technologies to penetrate high-value, advanced sectors like aerospace materials and digital solutions. By solving a complex aerospace engineering problem with adapted consumer packaging technology, TOPPAN is positioning itself as a vital player in next-generation telecommunications infrastructure.

Frequently Asked Questions (FAQ)

What is a HAPS aircraft?

High-Altitude Platform Stations (HAPS) are uncrewed, often solar-powered aircraft that fly in the stratosphere (around 20 kilometers above Earth). They act as “base stations in the sky,” providing wide-area cellular and internet coverage to the ground below, making them ideal for disaster recovery and connecting remote areas.

Why is the stratosphere so difficult for aircraft materials?

The stratosphere presents a combination of extreme environmental hazards. Materials must survive temperature swings from nearly -100°C to 100°C, intense UV-C radiation that breaks down chemical bonds, and highly concentrated ozone (10-20 ppm) that accelerates material degradation.

Sources

• TOPPAN Holdings and SoftBank Corp. Press Release