Samos 2


Samos 2
Mission typeReconnaissance
OperatorUnited States Air Force
Harvard designation1961 Alpha 1
COSPAR ID1961-001A
SATCAT no.00070Edit this on Wikidata
Mission duration1 month
Spacecraft properties
Spacecraft typeSamos-E1
Start of mission
Launch dateJanuary 31, 1961, 20:31:19 (1961-01-31UTC20:31:19Z) UTC
RocketAtlas LV-3A Agena-A 70D
Launch sitePoint Arguello LC-1-1
End of mission
Decay dateOctober 21, 1973
Orbital parameters
Reference systemGeocentric
RegimeSun-synchronous Low Earth
Perigee altitude474 kilometers (295 mi)
Apogee altitude553 kilometers (344 mi)
Inclination97.4 degrees
Period94.9 minutes

Samos 2 was an American reconnaissance satellite launched in 1961 as part of the Samos program. 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. Samos 2 was a Samos-E1 spacecraft, based on an Agena-A.[1]

The launch of Samos 2 occurred at 20:31:19 UTC on January 31, 1961. An Atlas LV-3A Agena-A rocket was used, flying from Launch Complex 1-1 at the Point Arguello Naval Air Station.[2] Ten minutes and fourteen seconds later, the Agena's engine cut off, having successfully achieved a low Earth orbit.[3] It was assigned the Harvard designation 1961 Alpha 1.

Samos 2 operated in a Sun-synchronous low Earth orbit, with an apogee of 553 kilometres (344 mi), a perigee of 474 kilometres (295 mi), an inclination of 97.4 degrees, and a period of 94.9 minutes.[4] The satellite had a mass of 1,915 kilograms (4,222 lb),[3] and measured 6.86 metres (22.5 ft) in length, with a diameter of 1.52 metres (5 ft 0 in).[5] It operated successfully, but the images returned were poor.[6] Designed to operate for around ten days,[1] it ceased operations around a month after launch,[3] and decayed from orbit on October 21, 1973.[4]


  1. ^ a b Krebs, Gunter. "Samos E-1". Gunter's Space Page. Retrieved June 17, 2010.
  2. ^ McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved June 17, 2010.
  3. ^ a b c McDowell, Jonathan. "SAMOS 2". The History of Spaceflight. Jonathan's Space Page. Retrieved June 17, 2010.
  4. ^ a b McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved June 17, 2010.
  5. ^ "Pioneer/Samos-A". FAS. Retrieved June 17, 2010.
  6. ^ Wade, Mark. "Samos". Encyclopedia Astronautica. Archived from the original on January 16, 2010. Retrieved June 17, 2010.