KH-5 4 (Discoverer 27)

The KH-5, also known as Keyhole 5 or codenamed Argon, served as the area survey component within the Corona program. Equipped with the Argon camera, also referred to as Corona-A, this single-frame camera was integrated with standard Corona hardware, including the return vehicle (SRV). Operating with a ground resolution of approximately 140 meters, the KH-5 relied on the Agena-B stage for three-axis control and propulsion throughout its mission. Upon completion, the SRV was deorbited using its own small solid rocket motor.