OV5-8
Orbiting Vehicle 5-8, was a materials science microsatellite launched, along with 12 other satellites in the biggest multi-satellite launch to date, on 18 August 1968 on the first Atlas Burner 2 rocket. The rocket and all payloads were lost when the second stage shroud collapsed after first stage cutoff. OV5-8 was the third satellite in the OV5 series of the United States Air Force's Orbiting Vehicle program.
Background
The Orbiting Vehicle satellite program arose from a US Air Force initiative, begun in the early 1960s, to reduce the expense of space research. Through this initiative, satellites would be standardized to improve reliability and cost-efficiency, and where possible, they would fly on test vehicles or be piggybacked with other satellites. In 1961, the Air Force Office of Aerospace Research created the Aerospace Research Support Program to request satellite research proposals and choose mission experiments. The USAF Space and Missiles Organization created their own analog of the ARSP called the Space Experiments Support Program, which sponsored a greater proportion of technological experiments than the ARSP. Five distinct OV series of standardized satellites were developed under the auspices of these agencies.The OV5 program was a continuation of the Environmental Research Satellite series developed by Space Technology Laboratories, a subdivision of TRW Inc. These were very small satellites launched pick-a-back with primary payloads since 1962—a natural fit under the Orbiting Vehicle umbrella. The primary innovation over the earlier ERS series was a command receiver, allowing instructions to be sent from the ground, and a Pulse-code modulation digital telemetry system, versus the analog transmitters used on prior ERS missions. Like prior ERS, the OV5s were spin-stabilized and heat was passively controlled. All of the OV5 series were built by TRW with the exception of OV5-6, built by AFCRL, and OV5-9, built by Northrop Corporation.