Missile Defense Alarm System

Origins

The launch of Sputnik 1 on October 4, 1957, from the Tyuratam range in the Kazakh SSR demonstrated that the Soviet Union possessed the capability to attack the United States with an intercontinental ballistic missile. The R-7 booster that launched Sputnik 1 and Sputnik 2 could carry a hydrogen bomb, raising the threat of a surprise nuclear attack. In response, the United States, Canada, and Denmark agreed to build the Ballistic Missile Early Warning System (BMEWS), with a main radar station at Thule Air Base in Greenland.

BMEWS used radar to detect incoming ICBM warheads and provide about 20 minutes of warning. However, radar limitations and the curvature of the Earth meant BMEWS could not detect warheads immediately after launch; only when they rose above the horizon could they be detected.

Calculations showed BMEWS would give ten to 25 minutes of warning. The planned MIDAS system would extend this to about 30 minutes, allowing Strategic Air Command's nuclear-armed heavy bombers to take off and thus deter a Soviet sneak attack by ensuring nuclear retaliation. MIDAS could also confirm radar detections from BMEWS, reducing the chance of a false alarm.

Development and costs

On March 16, 1955, the U.S. Air Force ordered development of an advanced reconnaissance satellite for continuous surveillance of preselected areas to determine an enemy's war-making capability. This led to the secret WS-117L program, which controlled the first generation of American reconnaissance satellites, including Corona and SAMOS. Lockheed-Martin, hired to design and manufacture these satellites, suggested additional satellite programs, including one using infrared sensors and a telescope to detect heat from heavy bombers and ICBMs.

After the Soviet launch of Sputnik, Subsystem G was added to WS-117L before the end of 1957. The Advanced Research Projects Agency (ARPA) took over Subsystem G and gave it the codename MIDAS in November 1958. In February 1959, ARPA submitted an initial development plan to the Air Force. MIDAS would use infrared sensors from above the Soviet Union to detect ICBM launches and give early warning of a thermonuclear attack.

The plan called for a 10-satellite research and development program from November 1959 to May 1961, after which a full operational system would be deployed. Because the information was time-sensitive, MIDAS could not use the film-canister dropping system of Discoverer/Corona/SAMOS. Instead, it transmitted warning signals via radio, sending messages about suspected missile launches and their time and location, not actual infrared images.

Program summary and launch history

The MIDAS program began on February 26, 1960, with MIDAS 1 launching on an Atlas-Agena A booster from LC-14 at Cape Canaveral. The Atlas burned successfully, but during coasting before staging, the Atlas LOX tank pressure dropped to zero and the missile tumbled while Agena telemetry ceased. The likely cause was inadvertent activation of the Agena Inadvertent Separation Destruct System (ISDS) charges. The ISDS was redesigned, and MIDAS 2's booster did not carry an ISDS during modifications.

MIDAS 2 launched successfully on May 24, but its attitude control system failed. Some infrared sensor data was returned before the telemetry system also failed. Planned experiments, including detection of ground flares and a Titan I missile test, were abandoned. The satellite remained in orbit until decaying in 1974.

The next launch occurred over a year later from Point Arguello's SLC-3 1-2. During this interval, two CORONA satellites carried and tested MIDAS sensors. MIDAS 3, the first operational model, launched on July 24, 1961, using the restartable Agena B stage. The Atlas's programmer reset during booster jettison, but the satellite reached orbit.

One solar panel failed to deploy, starving MIDAS 3 of power, and it died after a few orbits. MIDAS 4 launched on October 21; the Atlas lost roll control at T+186 seconds, placing the satellite in an incorrect trajectory. The Agena B exhausted its attitude control gas compensating, and by the time MIDAS 4 reached its transfer orbit, no gas remained for stabilization. It detected a Titan I launch from Cape Canaveral before one solar panel failed, and died a week into the mission when batteries ran down.

Investigation into MIDAS 4 and a similar SAMOS 4 failure found that retrorocket package heat shields on both Atlas boosters had broken off, exposing the gyroscope package to aerodynamic heating. A transistor in the roll output channel was also suspected and replaced with a different type, and the retrorocket heat shields were redesigned.