Space Cover 198, Discoverer 26 AKA Corona 9019
Discoverer 26, also known as Corona 9019, was an American optical reconnaissance satellite which was launched in 1961. It was a KH-2 (Keyhole-2) Corona' satellite, launched aboard an Agena-B. The KH-2 was second version in the Corona-program to build optical reconnaissance satellites. KH-1 flew on Discoverer 4 - 11, 14 and 15 and KH-2 flew on Discoverer 16 - 18, 22, 25, 26, and 28.
The KH-2 payload consisted of the improved C' (Corona prime) single panoramic camera and a single General Electric return vehicle (SRV, Satellite Return Vehicle). The film return capsule carried its own small solid-fuel retro motor to deorbit at the end of the mission with mid-air recovery of the returning capsule by a specially equipped aircraft.
The launch of Discoverer 26 occurred at 23:29:48 UTC on 7 July 1961. A Thor DM-21 Agena-B rocket was used, flying from Launch Complex 75-3-5 at the Vandenberg Air Force Base.
The covers above show a printed launch cover from Goldcraft Cachets and a Ted Holden rubber stamp cachet.
Discoverer 26 was operated in a low Earth orbit, with a perigee of 142 miles, an apogee of 443 miles, 82.9 degrees of inclination, and a period of 94 minutes. The satellite had a mass of 2,500 pounds, and was equipped with a panoramic camera with a focal length of 24 inches, which had a maximum resolution of 25 feet. Images were recorded onto 2.8 inch film, and returned in a Satellite Recovery Vehicle, which was deorbited two days after launch on July 10, 1961. The Satellite Recovery Vehicle used by Discoverer 26 was SRV-511. Once its images had been returned, Discoverer 26's mission was complete.
The covers above are for the recovery of the Satellite Recovery Vehicle on July 10, 1961. The first is a Ted Holden RSC cancelled at Vandenberg AFB which is the typical cancel location for Discovery recovery covers. The next two covers are interesting as they are cancelled from Honolulu near where the actual recovery took place. They both have a generic "Missile Launching" cachet but one has "Carried in the plane wich (sic) recovered the Discovere 26 Space Capsule" and the other has the handwritten notation "Discoverer 26 Catchers" with 8 signatures of the crew on the front and back of the cover. Interestingly, the cancel on the stamps looks to have no date as part of the cancel on either cover with the second cancel (the one not on the stamps) having a very clear date cancel (even though it doesn't show well on the scan the 1961 is clear on both of the actual postmarks).