Optus D3

{{Short description|Australian geostationary communications satellite}}

{{Use Australian English|date=January 2014}}

{{Use dmy dates|date=April 2025}}

{{Infobox spaceflight|auto=all

| name = Optus D3

| image =

| image_caption =

| mission_type = Communication

| operator = Optus

| website = http://www.optus.com.au/about/network/satellite/fleet/b3

| COSPAR_ID = 2009-044B

| SATCAT = 35756

| mission_duration = 15 years

| spacecraft_bus = Star-2.4

| manufacturer = Orbital Sciences

| dry_mass =

| launch_mass = {{convert|2401|kg}}

| power =

| launch_date = {{start-date|21 August 2009, 22:09|timezone=yes}} UTC

| launch_rocket = Ariane 5ECA

| launch_site = Kourou ELA-3

| launch_contractor = Arianespace

| entered_service =

| disposal_type =

| deactivated =

| orbit_epoch = 23 January 2015, 19:12:10 UTC{{cite web|url=http://www.n2yo.com/satellite/?s=35756|title=OPTUS D3 Satellite details 2009-044B NORAD 35756|publisher=N2YO|date=23 January 2015|access-date=25 January 2015}}

| orbit_reference = Geocentric

| orbit_regime = Geostationary

| orbit_periapsis = {{convert|35778|km|mi}}

| orbit_apoapsis = {{convert|35808|km|mi}}

| orbit_inclination = 0.05 degrees

| orbit_period = 1436.12 minutes

| orbit_longitude = 156° east

| apsis = gee

}}

Optus D3 is an Australian geostationary communications satellite, which is operated by Optus and provides communications services to Australasia. D3 was the third Optus-D satellite to be launched. It is a {{convert|2401|kg|adj=on}} satellite, which was constructed by Orbital Sciences Corporation based on the Star-2.4 satellite bus, with the same configuration as the earlier Optus D2 satellite.{{cite web|url=http://space.skyrocket.de/doc_sdat/optus-d2.htm|title=Optus D2, D3|last=Krebs|first=Gunter|publisher=Gunter's Space Page|access-date=2009-08-21}}

It was launched, along with the Japanese JCSAT-12 satellite, by Arianespace. An Ariane 5ECA rocket was used for the launch, which occurred from ELA-3 at the Guiana Space Centre in Kourou, French Guiana. The launch took place at 22:09 GMT on 21 August 2009, at the start of a 60-minute launch window.{{cite web|url=http://www.arianespace.com/news-mission-update/2009/621.asp|title=Preparations continue with the JCSAT-12 and Optus D3 payloads for Ariane 5's next launch|date=2009-08-12|work=Mission Update|publisher=Arianespace|access-date=2009-08-21}}

Optus D3 separated from its carrier rocket into a geosynchronous transfer orbit, from which it raised itself to geostationary orbit using an IHI -500-N apogee motor. It has a design life of fifteen years, and carries thirty two J band transponders (US IEEE Ku band).

Optus D3 will be visited by Mission Extension Vehicle-1, which will dock to Optus D3 and extend the mission of the satellite by 5-7 years.