A solar-powered surveillance drone boasting a wingspan larger than that of the Boeing 747 is capable of flying continuously for weeks or even months, as claimed by its operators. A test flight is currently underway off the US Gulf Coast this month.

Run by the US-Spanish venture Skydweller Aero, the Skydweller drone features a 72-meter wingspan, surpassing the width of most commercial jets. Weighing approximately 2,500 kilograms—similar to a Ford F-150 truck—this drone aims to achieve the first solar-powered flight globally, which was targeted for 2016, with a mission to carry out “pure targeted flights” over 13 kilometers during daylight, while aspiring towards building a “comparable solar-powered carbon fiber drone.”

The Skydweller drone executed the world’s inaugural autonomous solar-powered flight in April 2024, with several subsequent test flights conducted throughout the year. Military funding evaluations are focusing on the viability of marine drone patrols. Military funding is assessing the feasibility of marine drone patrols.

Most recently, the solar-powered drone accomplished its longest flight after departing from Stennis International Airport in Mississippi on July 20. According to the Flightradar24 Flight Tracking Service, it remained aloft over the Gulf Coast for more than three days, landing on July 23. The service also indicated that, on July 14, the drone had flown for over 18 hours.

The wingspan of the Skydweller drone is nearly double that of major surveillance drones, such as the Northrop Grumman RQ-4 Global Hawk used by the US Air Force. Its payload capacity of 400 kilograms significantly surpasses the lifting capabilities of most solar drones. Recently, the French aerospace company Thales contributed to the development of the Skydweller drone by equipping it with air surveillance radar. Equipment was provided for enhancing its capabilities.

However, experts suggest that the decades-long pursuit of commercializing solar drones has largely been marked by unmet promises and monumental failures. Arthur Holland Michele, a research partner at the Oslo Peace Institute, points out that both Google and Facebook attempted to create solar-powered drones for internet services but eventually discontinuing their initiatives. Aerospace manufacturer Airbus, too, has heavily invested in smaller Zephyr solar-electric drones, yet “we haven’t observed significant returns thus far,” states Michele.

“The military has funded solar drone demonstration flights for over ten years, and no one has yet acquired the technology,” Michele explains. “While solar drones are impressive and theoretically meaningful, their practical sustainability as a business case remains unclear.”