| Mission type | Reconnaissance |
|---|---|
| Operator | US Air Force |
| Mission duration | 4 months (planned) Failed to orbit |
| Spacecraft properties | |
| Spacecraft type | Samos-E2 |
| Bus | Agena-B |
| Start of mission | |
| Launch date | 9 September 1961, 19:28:27 UTC |
| Rocket | Atlas LV-3A Agena-B |
| Launch site | Point Arguello LC-1-1 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Sun-synchronous low Earth (planned) |
Samos 3 was an American reconnaissance satellite that was lost in a launch failure in 1961. [1] It was an early electro-optical reconnaissance spacecraft, meaning that it transmitted images to receiving stations on Earth rather than returning them in a film capsule, and it was intended to operate as part of the Samos programme. Samos 3 was the only Samos-E2 spacecraft to be launched. Samos-E2 satellites were based on the Agena-B platform and carried a camera with a focal length of 91 centimetres (36 in) and a ground resolution of 6 metres (20 ft). [2]
The launch of Samos 3 occurred at 19:28 UTC on 9 September 1961. An Atlas LV-3A Agena-B rocket was used, flying from Launch Complex 1-1 at Point Arguello Naval Air Station. [3] At the moment of liftoff, one of the launch tower umbilicals detached 0.21 seconds late. This tripped a switch in the Atlas, causing it to change from internal to external power. As a result, the booster's engines shut down, and the vehicle fell back onto the pad and exploded, destroying the satellite and causing extensive damage to the launch complex. [4]
Samos 3 was intended to operate in a Sun-synchronous low Earth orbit at an altitude of 480 kilometres (300 mi) with an inclination of 83 degrees. [4] The satellite had a mass of around 1,900 kilograms (4,200 lb), [4] and was designed to operate for around four months. [2] Damage to SLC3 mainly affected electrical and plumbing components and repair work began almost immediately. The pad was back online to host the launch of Samos 4 in November. Samos 3 was the last DOD-related launch to be unclassified, and afterwards, much greater secrecy would be put around such flights.
