Galaxy 11

{{short description|American geostationary communications satellite}}

{{Infobox spaceflight

| name = Galaxy 11

| image =

| image_caption =

| mission_type = Communication

| operator = PanAmSat
Intelsat

| website =

| COSPAR_ID = 1999-071A

| SATCAT =

| mission_duration = 15 years (planned)
{{time interval|22 December 1999, 00:50|show=ymd|sep=,}} (in progress)

| spacecraft_bus = HS-702

| manufacturer = Hughes S&C

| dry_mass =

| launch_mass = {{convert|4477|kg}}

| power =

| launch_date = {{start-date|22 December 1999, 00:50|timezone=yes}} UTC

| launch_rocket = Ariane 44L

| launch_site = Kourou ELA-2

| launch_contractor = Arianespace

| entered_service =

| disposal_type =

| deactivated =

| orbit_epoch = 21 January 2000{{cite web |last=McDowell |first=Jonathan |title=SATCAT |url=http://planet4589.org/space/log/satcat.txt |publisher=Jonathan's Space Pages |access-date=3 May 2018}}

| orbit_reference = Geocentric

| orbit_regime = Geostationary

| orbit_periapsis = {{convert|33612|km|mi}}

| orbit_apoapsis = {{convert|38050|km|mi}}

| orbit_inclination = 0.12 degrees

| orbit_period = 1438.36 minutes

| orbit_longitude = 78.5° West(1999-2000)
99° West (2000)
91° West (2000-2008)
93° West (2008)
32.8° East (2008—)

| orbit_slot =

| apsis = gee

| trans_band = 24 G/H band
40 J band

| trans_frequency =

| trans_bandwidth =

| trans_capacity =

| trans_coverage =

| trans_TWTA =

| trans_EIRP =

| trans_HPBW =

}}

Galaxy 11 is an American geostationary communications satellite which is operated by Intelsat. It is located in geostationary orbit at a longitude of 32.8 degrees east, where it serves as a backup to the Intelsat 802 spacecraft. It was originally operated at 99° West and later spent most of its operational life at 91° West, from where it was used to provide communications services to Brazil and North America.{{cite web|url=http://www.tbs-satellite.com/tse/online/sat_galaxy_11.html|title=Galaxy 11|access-date=2009-08-11|publisher=TSE}}

Galaxy 11 was built for PanAmSat by Hughes Space and Communications, and is based on the HS-702 satellite bus. It was the first HS-702 to be launched, and the first satellite to be equipped with an XIPS propulsion system. It carries 24 G/H band and 40 J band (IEEE C and {{Ku band}}s respectively) transponders, and at launch it had a mass of {{convert|4477|kg}}, with an expected operational lifespan of around 15 years.{{cite web|url=http://www.ucsusa.org/nuclear_weapons_and_global_security/space_weapons/technical_issues/ucs-satellite-database.html|title=UCS Satellite Database|publisher=Union of Concerned Scientists|date=2009-07-01|access-date=2009-08-10}}{{cite web|url=http://space.skyrocket.de/doc_sdat/galaxy-11.htm|title=Galaxy 11|first=Gunter|last=Krebs|publisher=Gunter's Space Page|access-date=2009-08-10}}

As the first HS-702 to fly, the Galaxy 11 was one of the six which were launched before a design flaw in the type's solar arrays was discovered. Solar concentrators, used to increase the amount of sunlight falling on the arrays, were fogging up due to vapours emitted by the satellite. This reduces the output of the solar arrays, and is expected to result in a reduced operational lifespan.{{cite book|last=Harland|first=David M|author2=Lorenz, Ralph D.|title=Space Systems Failures|publisher=Springer-Praxis|location=Chichester|year=2005|edition=2006|isbn=0-387-21519-0}} Following the discovery of the fault, US$130 million insurance was claimed on the satellite. The satellite was transferred to Intelsat when it merged with PanAmSat in 2006.

The launch of Galaxy 11 was conducted by Arianespace, using an Ariane 44L carrier rocket flying from ELA-2 at the Guiana Space Centre. The launch occurred at 00:50 UTC on 22 December 1999.{{cite web|url=http://planet4589.org/space/log/launchlog.txt|title=Launch Log|last=McDowell|first=Jonathan|publisher=Jonathan's Space Page|access-date=2009-08-10}} It successfully placed Galaxy 11 into a geosynchronous transfer orbit, from which it raised itself to a geostationary orbit by means of an onboard R-4D apogee motor. Its insertion into geosynchronous orbit occurred at 16:30 on 2 January 2000.{{cite web|url=http://planet4589.org/space/log/geo.date|title=Index|work=Geostationary Orbit Catalog|last=McDowell|first=Jonathan|publisher=Jonathan's Space Page|access-date=2009-08-10|archive-url=https://web.archive.org/web/20100406015538/http://www.planet4589.org/space/log/geo.date|archive-date=2010-04-06|url-status=dead}} The satellite was originally scheduled to be launched by Sea Launch, on the maiden flight of the Zenit-3SL, however the contract was transferred to Arianespace, and Sea Launch replaced Galaxy 11 with a DemoSat for their maiden flight.

It currently operates at 44.9° East.

On 10 September 2022, the International Scientific Optical Network coordinated by the Keldysh Institute of Applied Mathematics reported that Galaxy 11 had been partially destroyed in geostationary orbit, which is potentially dangerous for other satellites.{{cite web |url=https://t.me/kiam_ison_network/82|title=🚨На геостационарной орбите произошло частичное разрушение старого (1999 год запуска) телекоммуникационного аппарата Galaxy 11 |publisher=KIAM & ISON |access-date=10 September 2022 |language=Russian |date=10 September 2022}}{{cite news |title=Российские ученые зафиксировали частичное разрушение спутника США на орбите |url=https://www.interfax.ru/world/861481 |access-date=10 September 2022 |agency=Interfax |date=10 September 2022 |language=Russian}}

Despite the report from the Keldysh Institute of Applied Mathematics, the Galaxy 11 satellite continues to operate nominally with no disruption to communications service.