Intelsat III F-3

{{Short description|Geostationary communications satellite}}

{{Infobox spaceflight|auto=all

| name = Intelsat III F-3

| image =

| image_size = 180px

| image_caption = Intelsat III F-3.

| mission_type = Communications

| operator = Intelsat

| website =

| COSPAR_ID = 1969-011A

| SATCAT = 03674

| mission_duration = 5 years

| spacecraft_bus =

| spacecraft_type = Intelsat III

| manufacturer = TRW

| dry_mass =

| launch_mass = {{convert|293|kg|lb|abbr=on}}

| BOL_mass = {{convert|151|kg|lb|abbr=on}}

| dimensions =

| power = 183 watts

| launch_date = {{start-date|February 6, 1969, 00:39:00|timezone=yes}} UTC{{cite web|url=http://planet4589.org/space/log/launchlog.txt|title=Launch Log|first=Jonathan|last=McDowell|work=Jonathan's Space Page|access-date=February 9, 2014}}

| launch_rocket = Delta M

| launch_site = Cape Canaveral LC-17A

| launch_contractor = NASA{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1969-011A|title=INTELSAT 3 F-3|publisher=National Space Science Data Center|access-date=February 9, 2014}}

| disposal_type = Decommissioned

| deactivated = c.{{end-date|December 14, 1979}}

| orbit_epoch = January 23, 2015, 15:01:00 UTC{{cite web|url=http://www.n2yo.com/satellite/?s=03674|title=INTELSAT 3-F3 Satellite details 1969-011A NORAD 03674|publisher=N2YO|date=January 23, 2015|access-date=January 25, 2015}}

| orbit_reference = Geocentric

| orbit_regime = Geosynchronous
Now Graveyard

| orbit_periapsis = {{convert|39921|km|mi|abbr=on}}

| orbit_apoapsis = {{convert|41534|km|mi|abbr=on}}

| orbit_inclination = 18.33 degrees

| orbit_semimajor = {{convert|47100|km|mi|abbr=on}}

| orbit_period = 1695.49 minutes

| orbit_longitude = 174° east (1969)
63° east (1969-c.1975)

| apsis = gee

| trans_band =

| trans_frequency =

| trans_bandwidth =

| trans_capacity =

| trans_coverage =

| trans_TWTA =

| trans_EIRP =

| trans_HPBW =

| programme = Intelsat III

| previous_mission = Intelsat III F-2

| next_mission = Intelsat III F-4

}}

Intelsat III F-3 was a geostationary communications satellite operated by Intelsat. Launched in 1969 it was intended for operations over the Pacific Ocean; however, it spent most of its service life over the Indian Ocean at a longitude of 63 degrees east.{{cite web|url=http://space.jpl.nasa.gov/msl/QuickLooks/intelsat3QL.html|title=Intelsat 3 Quicklook|publisher=NASA Jet Propulsion Laboratory|work=Mission and Spacecraft Library|access-date=February 9, 2014}}

The third of eight Intelsat III satellites to be launched, Intelsat III F-3 was built by TRW. It was a {{convert|293|kg|lb|adj=on}} spacecraft, with its mass reducing to {{convert|151|kg|lb}} by entry into service as it burned propellant to reach its final orbit. The satellite carried an SVM-2 apogee motor for propulsion and was equipped with two transponders powered by body-mounted solar cells generating 183 watts of power.{{cite encyclopedia|url=http://www.astronautix.com/craft/intlsat3.htm|archive-url=https://web.archive.org/web/20020223094128/http://www.astronautix.com/craft/intlsat3.htm|url-status=dead|archive-date=February 23, 2002|title=Intelsat 3|first=Mark|last=Wade|encyclopedia=Encyclopedia Astronautica|access-date=February 9, 2014}} It was designed for 5 years of service life.{{cite web|url=http://space.skyrocket.de/doc_sdat/intelsat-3.htm|title=Intelsat-3|first=Gunter|last=Krebs|work=Gunter's Space Page|access-date=February 9, 2014}}

The launch of Intelsat III F-3 made use of a Delta M rocket flying from Launch Complex 17A at the Cape Canaveral Air Force Station. The launch, which was conducted by NASA, took place at 00:39:00 UTC on February 6, 1969, with the spacecraft entering a geosynchronous transfer orbit. Shortly after launch, Intelsat III F-3 fired its apogee motor to achieve geostationary orbit.

Intended to be operated over the Pacific Ocean at a longitude of 174° east, Intelsat III F-3 was moved to the less important Indian Ocean slot at 63° east after only three months in orbit due to concerns regarding its reliability. The satellite was only regarded as partially operable; however, it remained in service until April 1979, before being decommissioned in December of that year.{{cite web|url=http://planet4589.org/space/log/geo.log |title=Geostationary Satellite Log |first=Jonathan |last=McDowell |work=Jonathan's Space Page |access-date=February 9, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20160909151249/http://planet4589.org/space/log/geo.log |archive-date=September 9, 2016 |df=mdy-all }}{{cite web|url=https://history.nasa.gov/SP-4012/vol3/table4.103.htm|title=Chronology of Intelsat Development and Operations, 1969-1978|publisher=NASA History Office|work=NASA Historical Data Book|access-date=February 9, 2014}}

At the end of its service life, Intelsat III F-3 was raised into a higher orbit to reduce the probability of it colliding with an operational spacecraft. As of February 3, 2014 it remains in orbit, with a perigee of {{convert|39935|km|mi|sp=us}}, an apogee of {{convert|41521|km|mi|sp=us}}, inclination of 18.63 degrees and an orbital period of 28.25 hours.