Agena stage being loaded onto an Atlas rocket.
Fifty Years ago the US Air Force was attempting to place satellites in orbit that could warn us if an enemy country launched ballistic missiles at the USA. Named MIDAS (MIssile Defense Alarm System) the project would eventually launch nine satellites between 1960 and 1966. The sensors were primitive compared to later versions and often failed to detect launches. But the mission launched October 21, 1961 was successful. An Atlas-Agena rocket placed the MIDAS 4 sub-satellites into a polar orbit from the Pacific Missile Range.
Thor-Agena on the pad at Vandenberg AF Base in California.
On October 23, the USAF launched another Discoverer mission. Discoverer 33 failed to achieve polar orbit. The rocket shut down too early in the flight, and the spy satellite failed to separate and was lost into the Pacific.
On October 24, while scientists tracked the movement of the MIDAS sub-satellites in orbit over Earth, the Air Force launched a Titan ICBM from Cape Canaveral AF station. The small test MIDAS satellites detected the launch and successfully sent signals to Earth. This development helped our scientists plan on creating better sensors for the MIDAS satellites.
Polaris A1 on the test pad at Cape Canaveral.
Meanwhile on October 23, 1961, tests continued on the newest types of ICBMs, which were submarine-launched. The nuclear submarine USS Ethan Allen successfully fired off a Polaris A2, which was basically an improved Polaris A1. Eventually this missile design would enter srvice before the year was out and was placed on 13 submarines until 1974. This launch stands as the first underwater launch of the Polaris missile, and the tests were successful.
SSBN 608, USS Ethan Allen under way.
The USS Ethan Allen was the first submarine to be designed as a Ballistic Launch Nuclear Submarine. The first sub to launch a Polaris missile was the USS George Washington back in 1960, but that sub was modified from an attack submarine. The Ethan Allen had just completed trials and was commissioned in August 1961, before preparing for the Polaris tests.