Discoverer 35

{{short description|Reconnaissance satellite}}

{{Infobox spaceflight

| name = Discoverer 35

| image = KH-2_CORONA.jpg

| image_caption =

| mission_type = Optical reconnaissance

| operator = US Air Force/NRO

| Harvard_designation = 1961 Alpha Zeta 1

| SATCAT =

| mission_duration = 1 day

| spacecraft =

| spacecraft_type = Corona KH-2

| spacecraft_bus = Agena-B

| manufacturer = Lockheed

| launch_mass = {{convert|2100|kg}}

| launch_date = {{start-date|15 November 1961, 21:23|timezone=yes}} UTC

| launch_rocket = Thor DM-21 Agena-B 326

| launch_site = Vandenberg LC-75-3-4

| decay_date = {{end-date|3 December 1961}}

| landing_date =

| landing_site =

| orbit_epoch =

| orbit_reference = Geocentric

| orbit_regime = Low Earth

| orbit_periapsis = {{convert|233|km|mi|sp=us}}

| orbit_apoapsis = {{convert|247|km|mi|sp=us}}

| orbit_inclination = 81.6 degrees

| orbit_period = 89.3 minutes

| apsis = gee

| programme = Discoverer

| previous_mission = Discoverer 34

| next_mission = Discoverer 36

| programme2 = Corona KH-2

| previous_mission2 = Corona 9027

| next_mission2 =

}}

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.{{cite web|url=https://space.skyrocket.de/doc_sdat/kh-2.htm|title=KH-2 Corona|first=Gunter|last=Krebs|publisher=Gunter's Space Page|accessdate=23 October 2020}}

File:Thor Agena B with Discoverer 35 (Nov. 15 1961).gif

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.{{cite web|url=http://planet4589.org/space/log/launchlog.txt|title=Launch Log|first=Jonathan|last=McDowell|publisher=Jonathan's Space Page|accessdate=30 June 2010}} 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 {{convert|233|km}}, an apogee of {{convert|247|km}}, 81.6 degrees of inclination, and a period of 89.3 minutes.{{cite web|url=http://planet4589.org/space/log/satcat.txt|title=Satellite Catalog|first=Jonathan|last=McDowell|publisher=Jonathan's Space Page|accessdate=30 June 2010}} The satellite had a mass of {{convert|2100|kg}},{{cite web|url=http://www.astronautix.com/craft/kh3.htm|title=KH-3|first=Mark|last=Wade|publisher=Encyclopedia Astronautica|accessdate=30 June 2010|url-status=dead|archiveurl=https://web.archive.org/web/20100918005311/http://astronautix.com/craft/kh3.htm|archivedate=18 September 2010}} and was equipped with a panoramic camera with a focal length of {{convert|61|cm}}, which had a maximum resolution of {{convert|7.6|m}}.{{cite web|url=http://msl.jpl.nasa.gov/programs/corona.html|title=Corona|publisher=NASA|work=Mission and Spacecraft Library|accessdate=30 June 2010|url-status=dead|archiveurl=https://web.archive.org/web/20071003082210/http://msl.jpl.nasa.gov/Programs/corona.html|archivedate=3 October 2007}} Images were recorded onto {{convert|70|mm|adj=on|sp=us}} film, and returned in a Satellite Recovery Vehicle just over a day after launch. The Satellite Recovery Vehicle used by Discoverer 35 was SRV-523. 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.

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