Motherboard reports that "while America’s most expensive surveillance drone, the Northrop Grumman RQ-4 Global Hawk, can stay aloft for 32 hours, the Pentagon is looking for a drone that can fly nonstop for a week or more at a time, if two recently submitted solicitations are to go by."
"In a solicitation published last November, the Department of Defense (DoD) is calling on contractors to submit designs for a low cost, ultra-long endurance UAV that can perform intelligence, surveillance, and reconnaissance (ISR) missions for seven days or more. Specifically, the DoD wants to eliminate the need for launching new waves of drones to replace the ones that have run out of fuel and have to return to base."
“'The objective of this topic is to develop a low cost UAV with very long endurance, of at least seven days, that would enable the ISR mission to be accomplished with reduced manpower and system resources (esp. number of vehicles) to maintain near continuous coverage,' writes the DoD."