SKYDWELLER proposes a medium altitude pseudo-satellite for Greece

The intention to propose its renewable energy aircraft as a platform for intelligence gathering, surveillance and reconnaissance (ISR: Intelligence, Surveillance & Reconnaissance) to meet the Greek operational requirements in the Eastern Mediterranean, was announced by the American-Spanish start-up Skydweller Aero Inc.

The statement of Skydweller CEO Dr. Robert Miller (one of the co-founders of the company), is revealing: ““We are developing next-generation technology to meet the most significant global defense and national security concerns. With present threats to Greece in the Eastern Mediterranean, an ultra-persistent airborne platform, like Skydweller, would provide critical intelligence, surveillance, and reconnaissance (ISR) capabilities, providing a key strategic advantage in the region.”

It is recalled that the basic characteristics of the aircraft, its origins (an evolution of the solar-powered manned aircraft Solar Impulse 2) and information on renewable energy technologies used to power it, have been presented in a previous post. However, it is now clear that Skydweller Aero Inc., created by aircraft experts from Northrop Grumman’s Special Projects unit, aims to develop the aircraft to operate as a Medium-altitude pseudo-satellite (MAPS).

This approach does not follow the “tradition,” according to which solar-powered aircrafts are able to operate as high-altitude pseudo-satellites (HAPS), flying in the stratosphere, over the winds and weather, remaining in flight for weeks or even months. However, in order to be able to reach altitudes of 60,000 feet (18,288 meters), aircraft must have a super-lightweight structure and limited weight mission equipment. It is easily understood that the limited mission load capacity significantly reduces the operational capabilities as a platform for surveillance or communications relay.

This realization led Skydweller Aero Inc. in a different approach, where the ability to carry large payloads of increased capabilities becomes a much higher priority than flight altitude. It should be noted here that medium altitudes are a “death zone” for solar aircraft designers as winds and weather exert forces on the ultra-lightweight structure (therefore of reduced strength) which have been shown to be destructive. A typical example is the Airbus Zephyr, which in 2019 due to unstable weather conditions fell into an uncontrolled flight and eventually disintegrated in the air.

However, Skydweller evolving a platform based on the solar-powered Solar Impulse 2 aircraft, which in 2015-2016 flew around the world, recording 558.7 flight hours and covering a total distance of 22,195 nautical miles (41,105 km) in medium altitudes, has a different starting point, as the structure of the aircraft is already proven in extended flights at medium altitudes.

The UAV features 72 m wings that are covered with 2,900 ft2 (269.41 square meters) of photovoltaic (PV) cells, which are capturing renewable solar energy that is converted to 2 – 20 kW of power to support its payloads. Hydrogen fuel cells can also be added to increase the reliability of the propulsion system especially in poor weather conditions.

Skydweller’s design aims to offer government users an extremely persistent (up to 90 days), long-range and cost-effective platform for intelligence gathering, surveillance and reconnaissance (ISR) missions, communications relay and location reporting services, and timing. The above-mentioned advantages can also benefit commercial users for telecommunication services, offering broadband internet connection and remote sensing for commercial-industrial purposes.

It is understood that the launch of the Skydweller platform will revolutionize ISR operations. Today extended (24 hours a day / 7 days a week) ISR operations requires a large number of platforms. According to Skydweller, a long-endurance aircraft with 8-hr. time on station at 1,000 nm requires a minimum of three aircraft in constant rotation to cover 24 hr. If turnaround time and the scheduled maintenance are taken into account, then the number increases to four or five platforms.

However, with the use of the Skydweller platform that can provide persistence 24 hours a day, 7 days a week, the number of platforms, personnel and maintenance needs are dramatically reduced. Of course, to the financial benefit the cost of fuel, which for extended missions is anything but negligible, should be added.

Providing a Skydweller platform for Greece, in combination with its operational capabilities (especially the extreme persistence) and the renewable energy technologies it incorporates, makes the case extremely interesting at operational and technological level. Moreover, as it has already been announced, the development and utilization of renewable energy technologies is one of the main areas of strategic development of the country.