Discoverer 35


Discoverer 35
Mission typeOptical reconnaissance
OperatorUS Air Force/NRO
Harvard designation1961 Alpha Zeta 1
COSPAR ID1961-030A
SATCAT no.00201Edit this on Wikidata
Mission duration1 day
Spacecraft properties
Spacecraft typeCorona KH-2
Launch mass2,100 kilograms (4,600 lb)
Start of mission
Launch date15 November 1961, 21:23 (1961-11-15UTC21:23Z) UTC
RocketThor DM-21 Agena-B 326
Launch siteVandenberg LC-75-3-4
End of mission
Decay date3 December 1961 (1961-12-04)
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Perigee altitude233 kilometers (145 mi)
Apogee altitude247 kilometers (153 mi)
Inclination81.6 degrees
Period89.3 minutes

Discoverer 35, also known as Corona 9028, was an American optical reconnaissance satellite which was launched in 1961. It was the last of ten Corona KH-2 satellites, based on the Agena-B.[1]

The launch of Discoverer 35

The launch of Discoverer 35 occurred at 21:23 UTC on 15 November 1961. A Thor DM-21 Agena-B rocket was used, flying from Launch Complex 75-3-4 at the Vandenberg Air Force Base.[2] Upon successfully reaching orbit, it was assigned the Harvard designation 1961 Alpha Zeta 1.

Discoverer 35 was operated in a low Earth orbit, with a perigee of 233 kilometres (145 mi), an apogee of 247 kilometres (153 mi), 81.6 degrees of inclination, and a period of 89.3 minutes.[3] The satellite had a mass of 2,100 kilograms (4,600 lb),[4] and 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).[5] Images were recorded onto 70-millimeter (2.8 in) film, and returned in a Satellite Recovery Vehicle just over a day after launch.[4] The Satellite Recovery Vehicle used by Discoverer 35 was SRV-523.[2] The SRV was successfully recovered. Apart from the presence of some emulsion on the images it returned, Discoverer 35 completed its mission successfully. It subsequently remained in orbit until it decayed on 3 December 1961.[3]


  1. ^ Krebs, Gunter. "KH-2 Corona". Gunter's Space Page. Retrieved 23 October 2020.
  2. ^ a b McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 30 June 2010.
  3. ^ a b McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved 30 June 2010.
  4. ^ a b Wade, Mark. "KH-3". Encyclopedia Astronautica. Archived from the original on 18 September 2010. Retrieved 30 June 2010.
  5. ^ "Corona". Mission and Spacecraft Library. NASA. Archived from the original on 3 October 2007. Retrieved 30 June 2010.