| Weather Satellite|
10 August 1968
Hughes Aircraft Company
| ATS‑3, ATS‑2, ATS‑6, ATS‑1, Surveyor 7|
ATS-4 (Applications Technology Satellite) was a communications satellite launched by NASA on August 10, 1968 from Cape Canaveral through an Atlas-Agena D rocket.
The objective of ATS-4 was to investigate the possibilities of a gravity gradient stabilization system (the method of stabilizing artificial satellites).
The satellite has a cylindrical shape with a 142cm diameter and 183cm (about 360 cm considering the motor cover) with the surface covered by solar panels, and stabilized by gravity gradient.
A total of four experiments were conducted during the mission:Microwave Transponder
Gravity Gradient Stabilization
Image Orthicon (Day/Night) Camera
The ATS-4 launch vehicle failed in the ignition, resulting in an unplanned low elliptical orbit. The stress resulting from this orbit precipitated the fall of the spacecraft, yet, still achieved good results in some of the experiments. The primary objective to put a spacecraft stabilized by gravity gradient in orbit was not reached. The satellite reentered the atmosphere on 17 October 1968.