High Virgo - Weapons System 199C (WS-199C)

Proposals were considered for using the B-58 as a strategic missile launcher, and Lockheed built a 9.15 meter (30 foot) long solid fuel air launched ballistic missile (ALBM) derived from the company's X-17 test booster. The ALBM was test-launched four times in 1958 and 1959, with two successful trials. In the fourth and last launch, on 22 September 1959, the ALBM was supposed to be launched into space to take a picture of an American Explorer satellite under Project SNAP SHOT. This was a proof-of-concept test with applications for satellite inspection and anti-satellite interception, but that particular launch failed.

High Virgo, also known as Weapons System 199C (WS-199C), was a prototype air-launched ballistic missile (ALBM) jointly developed by Lockheed and the Convair division of General Dynamics during the late 1950s. The WS-199A designation applied to Strategic Air Command system studies in general, while three other subprojects flight tested actual hardware. The missile proved moderately successful and aided in the development of the later GAM-87 Skybolt ALBM; in addition, it was used in early test of anti-satellite weapons.

As part of the WS-199 project to develop new strategic weapons for the United States Air Force's Strategic Air Command, the Lockheed Corporation and the Convair division of General Dynamics proposed the development of an air-launched ballistic missile, to be carried by the Convair B-58 Hustler supersonic medium bomber. In early 1958 the two companies were awarded a contract for development of the weapon, designated WS-199C, under the code-name "High Virgo". While the project was a research-and-development exercise, it was planned that an operational weapon could be quickly developed into an operational system if required.

The High Virgo missile was a single-stage weapon, powered by a solid-fueled Thiokol TX-20 rocket, and was equipped an advanced inertial guidance system derived from that of the AGM-28 Hound Dog cruise missile. Four tailfins in a cruciform arrangement provided directional control. The missile was developed by Lockheed, utilising components developed for several existing missiles in order to reduce the cost of the project, and to reduce development time. Convair was responsible for development of a pylon for carriage and launching of the missile from the prototype B-58, the pylon replacing the aircraft's normal weapons pod.

Four test flights of the High Virgo missile were conducted. With development problems, the first two did not include the inertial guidance system, instead being fitted with a simple autopilot guiding the weapon on a pre-programmed course. Launched from the B-58 carrier aircraft at high altitude and supersonic speed, the initial flight, conducted on 05 September 1958, was a failure when the missile's controls malfunctioned. The second test, three months later, proved more successful, with the missile flying a range of nearly 200 miles (320 km). The third flight test, in June 1959, used the inertial guidance system for the first time; it, too, was a successful flight.

The fourth High Virgo missile was utilized in a test mission, under Project SNAP SHOT, intended to demonstrate the capability of the missile for use as a "satellite interceptor", or anti-satellite (ASAT). The missile, modified with cameras to record the results of the test, was initially targeted at the Explorer 4 satellite, but due to errors in calculating the satellite's orbit, Explorer 5 was targeted instead. The ASAT test mission, the final flight of the High Virgo missile, was conducted on 22 September 1959. Less than a minute after the launch of the missile from the B-58 carrier aircraft at Mach 2, the telemetry signal was lost. No data was recovered from the test, and the camera data, intended to be recovered afterward, was not located; therefore the test was inconclusive.

No further test firings of High Virgo were conducted, the research project having been concluded. However the Air Force was already undertaking work on what became the GAM-87 Skybolt missile, which incorporated lessons learned from the WS-199 project in its construction.