S-45A

S-45A was an American satellite, which was lost in a launch failure in 1961. The satellite was intended to operate in a highly elliptical orbit, from which it was to have provided data on the shape of the ionosphere,[1] and on the Earth's magnetic field.[2] It was part of the Explorer programme, and would have been designated Explorer 12 had it reached orbit. It was the second of two identical satellites to be launched; the first, S-45, had also been lost in a launch failure, earlier in the year.[2]

S-45A

An S-45 satellite before launch
Mission type	Ionospheric
Operator	NASA
Mission duration	Failed to orbit
Spacecraft properties
Launch mass	33.6 kilograms (74 lb)
Start of mission
Launch date	24 May 1961, 19:48:05 (1961-05-24UTC19:48:05Z) UTC
Rocket	Juno II AM-19G
Launch site	Cape Canaveral LC-26B
Orbital parameters
Reference system	Geocentric
Regime	Highly elliptical (planned)
Explorers

S-45A was launched aboard a Juno II rocket, serial number AM-19G. It was the final flight of the Juno II.[3] The launch took place from Launch Complex 26B at the Cape Canaveral Air Force Station at 19:48:05 UTC on 24 May 1961.[3] The system which was intended to ignite the second stage malfunctioned, and as a result that stage failed to ignite.[4] The rocket failed to achieve orbit.[5]