HAP-alpha – the uncrewed high-altitude platform

Visualisation of the final HAP-alpha design
The HAP-alpha uncrewed high-altitude platform will ultimately be capable of reaching the lower stratosphere, at an altitude of approximately 20 kilometres.
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DLR project team in front of the HAP-alpha wing in an aircraft hangar in Braunschweig
Members of the DLR project team responsible for the aircraft structure stand in front of the HAP-alpha wing in the Braunschweig hangar. The wing was developed by DLR and constructed using an extremely lightweight design. It has a wingspan of 27 metres but weighs just 40 kilograms. The high-altitude platform wing was assembled in the aircraft hangar in Braunschweig.
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Visualisation of the uncrewed HAP-alpha high-altitude platform
DLR scientists and researchers from 16 participating institutes and facilities in the fields of aeronautics, space and security have contributed their expertise to the development and unique design of the uncrewed high-altitude platform HAP-alpha.
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Uncrewed stratospheric aircraft, also known as high-altitude platforms (HAPs), offer a sustainable alternative to satellites for Earth observation and communication tasks. HAPs can be manufactured and launched more cost-effectively than their counterparts in Earth orbit, and can also be landed and reused for other missions. HAP-alpha is a collaborative project involving 16 DLR institutes and facilities, aiming to build and flight-test an uncrewed, solar-powered high-altitude platform as a technology demonstrator. The HAP-alpha platform is ultimately intended to fly in the lower stratosphere, at altitudes of approximately 20 kilometres.

High-altitude, uncrewed and solar-powered platforms are attracting increasing interest in research and industry due to their wide range of potential applications.

In contrast to aircraft and non-geostationary satellites, HAPs can be permanently stationed at almost any location. They operate autonomously, like satellites, but – unlike satellites – can take off and land, making it possible to service the system and equip it with different payloads. In addition to conventional applications such as remote sensing or in situ measurements for Earth observation, HAPs can be deployed in crisis areas or serve as nodes in communication networks.

The goal of the cross-institutional HAP-alpha project is to establish comprehensive system-level expertise in high-altitude aircraft at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR). This knowledge will support the development, construction and operation of a fully certifiable overall system (platform, payload, ground station, operational procedures) suitable for continuous operation.

Thanks to advanced lightweight construction concepts, miniaturisation in sensor and avionics technologies, and further developments in storage systems, a wide range of applications feasible.

Beyond basic research and building up internal expertise, DLR is also working in consultation with regulatory authorities to help establish legal frameworks that will allow such platforms to be operated in controlled airspace. One example is DLR's contribution to the Joint Authorities for Rulemaking on Unmanned Systems (JARUS).

HAP-alpha project – an uncrewed high-altitude platform

  • Duration: January 2018 to December 2025
  • Leading institute: Institute of Flight Systems
  • Project type: HGF Programmorientierte Förderung
  • Funding body: DLR Programme Directorate for Aeronautics, Space and Security

Participating DLR institutes and facilities

In­sti­tute of Flight Sys­tems

Responsible for the overall administrative and technical management of the project, as well as for the flight mechanical design, avionics, propulsion, simulation systems, flight control, mission management, integration planning and flight test planning.

German Remote Sensing Data Center (DFD)

Responsible for the communications component of the ground segment, specifically the mobile receiving unit.

Institute of Aeroelasticity

Responsible for the aeroelastic design of HAP-alpha and, together with other institutes involved in this phase, established a design loop for the overall design of the aircraft.

Institute of Aerodynamics and Flow Technology

Responsible for the aerodynamic design of the aircraft and the propellers. Together with other institutes involved in the design, it established a design loop for the overall aircraft design.

Institute of Electrified Aero Engines

Leads administrative work on the propulsion system and contributed to the design of the electric propulsion units.

Institute of Flight Guidance

Responsible for the operator segment of the ground station, where pilots and flight test crew are located. It has also adapted DLR’s UFly guidance software to the needs of HAP-alpha.

Microwaves and Radar Institute

Responsible for developing the synthetic aperture radar (SAR) for HAP-alpha. 'HAPSAR' offers a 50-by-50-centimetre resolution, consumes less than 250 Watts of power and weighs just five kilograms.

Institute of Communications and Navigation

Designed and is responsible for the onboard communication systems of the aircraft.

Remote Sensing Technology Institute

Responsible for developing AI-supported evaluation methods for optical images from the high-resolution camera system (MACS-HAP) and synthetic aperture radar (SAR).

Institute of Optical Sensor Systems

Now merged into the Institute of Space Research, is developing the high-resolution camera system. 'MACS-HAP' has a ground resolution of 15 centimetres from an altitude of 20 kilometres and weighs less than five kilograms including its pan/tilt mechanism. The institute is also leading the payload sub-project.

Institute of Atmospheric Physics

Supports the project by collecting and evaluating weather data for the initial selection of potential flight test areas and for flight test campaigns.

Institute of Software Technology

Responsible for developing and maintaining the core software of the flight control computer.

Institute of System Dynamics and Control

Now part of the Institute of Flight Systems.

Institute of Lightweight Systems

Responsible for the design and construction of the aircraft structure made from carbon-fibre-reinforced polymer (CFRP). Participated in the design loop with other institutes involved in the overall aircraft design.

Institute of Networked Energy Systems

Responsible for the solar generator component of the propulsion system.

Systemhaus Technik

Supports the development of the aircraft's computer-aided design (CAD) model and has manufactured major structural components. The institute is also responsible for the design and construction of the launch vehicle and the airframe's transport structures.

Contact

Florian Nikodem

Project management
German Aerospace Center (DLR)
Institute of Flight Systems
Safety Critical Systems and Systems Engineering
Lilienthalplatz 7, 38108 Braunschweig