Samos 3 was an American reconnaissance satellite which was lost in a launch failure in 1961. 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 was to have been operated as part of the

Samos Samos (, also ; el, Σάμος ) is a Greece, Greek island in the eastern Aegean Sea, south of Chios, north of Patmos and the Dodecanese, and off the coast of western Turkey, from which it is separated by the -wide Mycale Strait. It is also a se ...

programme. Samos 3 was the only Samos-E2 spacecraft to be launched. Samos-E2 satellites were based on an Agena-B, and carried a camera with a focal length of , and a resolution of . 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 the

Point Arguello Point Arguello ( Spanish: ''Punta Argüello'') is a headland on the Gaviota Coast, in Santa Barbara County, California, near the city of Lompoc. The area was first used by the United States Navy in 1959 for the launch of military and soundin ...

Naval Air Station. At the moment of liftoff, one of the launch tower umbilicals detached 0.21 seconds late. This tripped a switch in the Atlas and caused it to change from internal to external power. The booster's engines shut off and it fell back onto the pad and exploded, destroying the satellite and causing extensive pad damage. Samos 3 was to have operated in a Sun-synchronous

low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...

, at an altitude of and with 83 degrees of

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

. The satellite had a mass of around , and was designed to operate for around four months. 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.

References

{{Orbital launches in 1961 Spacecraft launched in 1961 Satellite launch failures