Discoverer 18 (KH-2 3)

Launch data: Designation 00067 / 1960 Sigma1 / 60018A Launch date 07 Dec 1960 - 20:20:58 UT Launch site Va, LC75-3 pad 4 Launch vehicle Thor-DM21 Agena-B (#296) Mission  Optical reconnaissance Low Earth orbit on: Perigee / Apogee  243 / 661 km Inclination  81,50° Period  93,66 min

Mission details:

• The launch of Discoverer 18 occurred at 20:20:58 UTC on 7 December 1960. A Thor DM-21 Agena-B rocket was used, flying from Launch Complex 75-3-4 at the Vandenberg Air Force Base. Upon successfully reaching orbit, it was assigned the Harvard designation 1960 Sigma 1.
• Discoverer 18 was operated in a low Earth orbit, with a perigee of 272 kilometres (169 mi), an apogee of 535 kilometres (332 mi), 81.4 degrees of inclination, and a period of 92.6 minutes. The satellite was equipped with a panoramic camera with a focal length of 61 centimetres (24 in), which had a maximum resolution of 7.6 metres (25 ft). Images were recorded onto 70-millimetre (2.8 in) film, and returned in a Satellite Recovery Vehicle, which was recovered three days after the launch. The Satellite Recovery Vehicle used by Discoverer 18 was SRV-508. Following the return of its images, Discoverer 18 remained in orbit until it decayed on 02 April 1961. It was the first KH-2 satellite to complete its mission successfully.