What is the primary purpose of unmanned aircraft systems (UAS)?

The primary purpose of unmanned aircraft systems (UAS) is indeed to perform tasks without a human pilot onboard. This capability enables various applications, ranging from military operations to commercial activities, where remote or autonomous operation can enhance efficiency, safety, and cost-effectiveness. By removing the pilot from the aircraft, UAS can access areas that might be too dangerous or difficult for manned aircraft to navigate, such as disaster zones, or perform repetitive tasks with precision, like agricultural monitoring or surveillance.

While other options may highlight secondary functions or benefits of UAS, the core purpose is centered around their unmanned nature, which fundamentally distinguishes them from traditional aircraft that rely on human pilots for operation.