EchoStar XXI

{{Short description|Communications satellite}}

{{Infobox spaceflight

| name = EchoStar XXI

| image =

| image_caption =

| mission_type = Communication

| operator = EchoStar Corporation

| website =

| COSPAR_ID = 2017-032A

| SATCAT = 42749

| mission_duration = Planned: 15+ years
Elapsed: {{time interval|8 June 2017 03:45|show=ymd|sep=,}}

| spacecraft_bus = SSL 1300

| manufacturer = Space Systems Loral

| dry_mass =

| launch_mass = {{convert|6871|kg}}

| power =

| launch_date = {{start-date|8 June 2017, 03:45|timezone=yes}} UTC

| launch_rocket = ILS Proton Breeze M

| launch_site = Baikonur Cosmodrome

| launch_contractor = International Launch Services

| entered_service =

| disposal_type =

| deactivated =

| orbit_epoch = 22 July 2018, 15:03 UTC{{cite web|url=https://www.n2yo.com/satellite/?s=42749|title=EchoStar XX1 Satellite details 2017-032A NORAD 42749|work=N2YO|date=22 July 2018|accessdate=22 July 2018}}

| orbit_reference = Geocentric

| orbit_regime = Geostationary

| orbit_periapsis = {{convert|35784.4|km|mi|sp=us}}

| orbit_apoapsis = {{convert|35801.8|km|mi|sp=us}}

| orbit_inclination = 6.8 degrees

| orbit_period = 23.93 hours

| orbit_longitude = 10.25° East

| orbit_slot =

| apsis = gee

| trans_band = S-band

| trans_frequency =

| trans_bandwidth =

| trans_capacity =

| trans_coverage = Europe

| trans_TWTA =

| trans_EIRP =

| trans_HPBW =

}}

EchoStar XXI (formerly known as TerreStar 2{{cite web|url=https://spaceflight101.com/proton-echostar-21/echostar-21/|title=Echostar 21|date=8 June 2017 |accessdate=2018-07-22}}) is a European communications satellite which is operated by Echostar Corporation. It was constructed by Space Systems/Loral, based on the SSL 1300 satellite bus, and carries S band transponders which will be used to provide 2 GHz mobile connectivity throughout Europe.

EchoStar XXI was launched at 03:45 UTC on June 8, 2017{{cite web|url=https://www.echostar.com/en/Press/Newsandmedia/EchoStar%20XXI%20Satellite%20Successfully%20Launched.aspx|title=EchoStar XXI Satellite Successfully Launched|publisher=EchoStar Corporation|date=2017-06-08|accessdate=2018-07-22}} from the Baikonur Cosmodrome in Kazakhstan. This satellite was the heaviest commercial payload flown aboard a Russian booster at the time of its launch.{{cite web|url=https://spaceflightnow.com/2017/06/08/video-proton-rocket-returns-to-service-with-launch-of-echostar-21/|title=Video: Proton rocket returns to service with launch of EchoStar 21|accessdate=2018-07-22}}

Before being launched, the satellite was known as TerreStar-2, a ground spare for TerreStar Networks' satellite-terrestrial telephone network.{{cite web|url=https://spacenews.com/terrestar-2-final-payload-integration/|title=TerreStar-2 in Final Payload Integration|date=26 April 2010|accessdate=2018-07-22}}