The Future of Advanced Air Mobility

Hypersonic Aircraft Developer Destinus Resumes Test Flights with 'Jungfrau' Prototype

Destinus, a Swiss start-up that aims to develop a hydrogen-powered hypersonic aircraft for high-speed cargo deliveries, has resumed test flights with its Jungfrau technology demonstrator after the initial test flight of a second, larger prototype didn’t go as smoothly as planned. 

The company is developing a fully autonomous aircraft that can fly at hypersonic speeds exceeding Mach 5, or five times the speed of sound. This “near-space” hyperplane would operate in the mesosphere, flying higher than any existing aircraft, and it will be able to make cargo deliveries anywhere in the world in under two hours, according to Destinus. “The hyperplane they are building combines the technological advancements of a rocket with the simple physics of a glider,” a company spokesman told FutureFlight

Jungfrau, the company’s first technology demonstrator, made its first flight in November 2021, after which it returned to the hangar at Payerne Airport in Switzerland for hardware and software upgrades. The aircraft flew several loops at subsonic speeds and successfully landed, verifying that the airframe, which is designed for hypersonic flights, could perform at subsonic speeds as well. Destinus resumed subsonic flight testing with the upgraded Jungfrau in July, but the company has yet to break the sound barrier with either of its prototypes. 

The larger prototype, called Eiger, made its inaugural test flight on April 13 at an airport near Munich, Germany, according to a company blog post. For that mission, Destinus sought to determine how the aircraft would perform while flying at low speeds and during takeoff and landing. However, the prototype experienced an “aerodynamic instability” a few minutes into the flight and made a “hard landing,” Destinus officials wrote in the blog post. Eiger has since returned to the hangar, where the team is conducting a thorough investigation and making design changes before it's cleared to resume flight testing. 

“Although the flight did not go as planned, significant data points were collected from internal and external sensors that will help the engineers validate their analysis and provide new insights,” Destinus said in the blog. “This is a great opportunity for us to learn more about this challenging shape!”

One of the biggest challenges Destinus faces is designing an airframe that can fly not only at hypersonic speeds, but also at slower subsonic and supersonic speeds. That’s because hypersonic aircraft still need to be able to take off and land at slower-than-hypersonic speeds. 

“Although very efficient for hypersonic flights, both Jungfrau and Eiger have shapes that differ from common subsonic airframes,” Destinus wrote in its blog. “There will not be a single shape that can tackle subsonic, supersonic, and hypersonic flight regimes all in a single mission. This is because different geometrical features are tailored to each specific regime. Therefore, flying hypersonic shapes such as Jungfrau at subsonic speeds is a very challenging task, in which Destinus is succeeding.” 

Destinus's Eiger prototype is pictured on the runway.
Destinus's Eiger prototype is pictured on the runway. (Credit: Destinus)

The company is not yet using liquid hydrogen to power its prototypes, but it expects to begin testing its first hydrogen-fed air turborocket (ATR) engine in 2023, the company spokesman told FutureFlight. For now, the company’s prototypes are powered by turbojet engines. 

Destinus says it is working with EASA and other aviation regulators on the certification basis for this new type of aircraft, which has so far only been approved to conduct test flights at subsonic speeds. The company hopes to have a third prototype flying at supersonic speeds by the end of 2022, and it will introduce the ATR engines on subsequent prototypes that could begin hypersonic test flights between 2023 and 2024.