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Satellite Data System

{{Short description|American military satellite communication system}}

{{Use American English|date=January 2019}}

{{Use dmy dates|date=January 2021}}

File:SDS3 const.png type and two geostationary satellites]]

The Satellite Data System (SDS) is a system of United States military communications satellites. At least three generations have been used: SDS-1 from 1976 to 1987; SDS-2 from 1989 to 1996; SDS-3 from 1998 to the present. It is believed that these satellites were known by the code name Quasar.[http://planet4589.org/nro/nro.html Jonathan's Space Report: NRO Satellite Names] The first generation was named simply 'SDS', the second generation was named 'Quasar' and the third generation each had their own designations.[http://planet4589.org/space/log/satcat.txt Jonathan's Space Report: Satellite Catalogue]

Orbital characteristics

SDS satellites have a highly elliptical orbit, going from about 300 kilometers at perigee to roughly 39,000 km at apogee in order to allow communications with polar stations that cannot contact geosynchronous satellites. The high apogee meant that the polar regions were visible for long amounts of time, and only two satellites were required in order to achieve constant communications ability. In addition, two geostationary satellites appear to be part of the system. The SDS satellites were constructed by Hughes Aircraft Company.

Mission

The primary purpose of the SDS satellites is to relay imagery from low-flying reconnaissance satellites, notably the Keyhole optical reconnaissance and Lacrosse/Onyx radar reconnaissance satellites to ground stations in the United States.{{cite book |last=Richelson |first=J.T. |date=2001 |title=The Wizards of Langley. Inside the CIA's Directorate of Science and Technology |location=Boulder, Colorado |publisher=Westview Press |isbn=9780813340593}}

SDS-1

File:NRO comm satellite.PNG

File:USA179 SDS 3 4.jpg

Each SDS-1 satellite had 12 channels available for Ultra high frequency (UHF) communication. They were cylindrical in shape, roughly {{cvt|25|ft|m}} long. 980 watts of electrical power were available from solar panels and batteries. The SDS-1 had a mass of {{cvt|630|kg}} and was launched on Titan-3B rockets. The SDS-1 satellites had similar orbits to the Air Force's Jumpseat ELINT satellites.[http://www.zianet.com/jpage/black/NRO%20Brochure.pdf National Reconnaissance Office: "NRO Brochure circa 1997"]{{dead link|date=December 2017|bot=InternetArchiveBot|fix-attempted=yes}}

It has been speculated that the early satellites served as data relays for the first KH-11 Kennen reconnaissance satellites.{{cite web|first=Dwayne A.|last=Day|date=26 February 2018|url=http://www.thespacereview.com/article/3440/1|title=Shadow dancing: the Satellite Data System|publisher=The Space Review}}

SDS-2

The SDS-2 is significantly more massive at {{cvt|2335|kg}}, with three separate communication dishes, including one for a K-band downlink. Two dishes are {{cvt|4.5|m}} in diameter, while the third is {{cvt|2|m}} in diameter. The solar arrays generate 1238 watts of power. It is believed that the Space Shuttle has been used to launch several satellites, possibly on missions STS-28, STS-38, and STS-53. Other launches have used the Titan IV launch vehicle.

Satellites

{|class="wikitable"

|-

! Name

! COSPAR ID[http://planet4589.org/space/log/ Jonathan's Space Report: List of satellite launches]
SATCAT №

! Launch date

! Launch vehicle

! Launch site

! Launch designation

! Perigee

! Apogee

! Inclination

! Remarks

|-

| colspan=10|

= First generation =

|-

| OPS 7837

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1976-050A 1976-050A]
08871

| 2 June 1976

| Titan III(34)B

| VAFB, SLC-4W

| SDS F-1

| 380 km

| 39315 km

| 63.3 deg

|

|-

| OPS 7940

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1976-080A 1976-080A]
09270

| 6 August 1976

| Titan III(34)B

| VAFB, SLC-4W

| SDS F-2

| 380 km

| 39315 km

| 63.3 deg

|

|-

| OPS 7310

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1978-075A 1978-075A]
10993

| 5 August 1978

| Titan III(34)B

| VAFB, SLC-4W

| SDS F-3

| 380 km

| 39315 km

| 63.3 deg

|

|-

| OPS 5805

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1980-100A 1980-100A]
12093

| 13 December 1980

| Titan III(34)B

| VAFB, SLC-4W

|

|

|

|

|

|-

| USA-4

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1984-091A 1984-091A]
15226

| 28 August 1984

| Titan III(34)B

| VAFB, SLC-4W

| SDS F-5A

|

|

|

|

|-

| USA-9

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1985-014A 195-014A]
15546

| 8 February 1985

| Titan III(34)B

| VAFB, SLC-4W

| USA-9

|

|

|

|

|-

| USA-21

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1987-015A 1987-015A]
17506

| 15 February 1987

| Titan III(34)B

| VAFB, SLC-4W

| SDS F-6

|

|

|

|

|-

| colspan=10|

= Second generation =

|-

| USA-40

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1989-061B 1989-061B]
20167

| 2 June 1989

| {{OV|102}}
STS-28/Orbus-21S

| KSC, LC-39B

| rowspan=4| N/A

|

|

|

|

|-

| USA-67

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1990-097B 1990-097B]
20963

| 15 November 1990

| {{OV|104}}
STS-38/Orbus-21S

| KSC, LC-39A

|

|

|

| Geosynchronous satellite, deployed along with Prowler and initially misidentified as a Magnum SIGINT spacecraft

|-

| USA-89

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1992-086B 1992-086B]
22518

| 2 December 1992

| {{nowrap|{{OV|103}}}}
STS-53/Orbus-21S

| KSC, LC-39A

|

|

|

|

|-

| USA-125

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1996-038A 1996-038A]
23945

| 3 July 1996

| Titan IV(405)A

| CCAFS, LC-40

|

|

|

|

|-

| colspan=10|

= Third generation =

|-

| USA-137

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1998-005A 1998-005A]
25148

| 29 January 1998

| Atlas IIA

| CCAFS, SLC-36A

| NROL-5

|

|

|

| Capricorn, Molniya orbit

|-

| USA-155

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2000-080A 2000-080A]
26635

| 6 December 2000

| Atlas IIAS

| CCAFS, SLC-36A

| NROL-10

|

|

|

| Great Bear, geosynchronous satellite at 10° West

|-

| USA-162

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2001-046A 2001-046A]
26948

| 11 October 2001

| Atlas IIAS

| CCAFS, SLC-36B

| NROL-12

|

|

|

| Aquila, geosynchronous satellite at 144° West

|-

| USA-179

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2004-034A 2004-034A]
28384

| 31 August 2004

| Atlas IIAS

| CCAFS, SLC-36A

| NROL-1

|

|

|

| Nemesis, Molniya orbit, final Atlas II launch

|-

| USA-198

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2007-060A 2007-060A]
32378

| 10 December 2007

| Atlas V 401

| CCAFS, SLC-41

| NROL-24

|

|

|

| Scorpius, Molniya orbit

|-

| USA-227

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2011-011A 2011-011A]
37377

| 11 March 2011

| Delta IV-M+(4,2)

| CCAFS, SLC-37B

| NROL-27

|

|

|

| Gryphon, geosynchronous satellite at 10° West, replaced USA-155

|-

| USA-236

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2012-033A 2012-033A]
38466

| 20 June 2012

| Atlas V 401

| CCAFS, SLC-41

| NROL-38

|

|

|

| Drake, geosynchronous satellite at 144° West, replacement for USA-162

|-

| USA-252

| [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2014-027A 2014-027A]
39751

| 22 May 2014

| Atlas V 401

| CCAFS, SLC-41

| NROL-33

|

|

|

| Geosynchronous satellite

|-

| USA-269

| {{COSPAR|2016-047A}}
41724

| 28 July 2016

| Atlas V 421

| CCAFS SLC-41

| NROL-61

|

|

|

| Spike, Geosynchronous orbit, might be a new generation {{cite news|url=https://spaceflightnow.com/2016/07/30/nrol-61-satellite-launched-thursday-spotted-in-space-by-sky-watchers/|title=NROL-61 satellite launched Thursday spotted in space by sky-watchers|publisher=Spaceflight Now|date=July 30, 2016}}

|-

| USA-279

| {{COSPAR|2017-066A}}
42973

| 15 October 2017

| Atlas V 421

| CCAFS, SLC-41

| NROL-52

|

|

|

| Likely Geosynchronous orbit{{cite news|url=https://www.nasaspaceflight.com/2017/10/ula-atlas-v-nrol-52-launch-cape-canaveral/|title=Atlas V finally launches with NROL-52 |publisher=NASASpaceFlight.com|first=William|last=Graham|date=October 15, 2017|access-date=October 15, 2017}}

|}

References

{{Portal|Spaceflight}}

{{Reflist|30em}}

  • Vick, Berman, Lindborg, Fellow (March 19, 1997) [https://fas.org/spp/military/program/com/sds_1.htm SDS-1 Military Communications Satellite] {{Webarchive|url=https://web.archive.org/web/20160828024008/http://fas.org/spp/military/program/com/sds_1.htm |date=28 August 2016 }} Federation of American Scientists Accessed April 24, 2004
  • Vick, Berman, Lindborg, Fellow, Pike, Aftergood (March 19, 1997) [https://fas.org/spp/military/program/com/sds_2.htm SDS-2 Military Communications Satellite] {{Webarchive|url=https://web.archive.org/web/20160920050553/https://fas.org/spp/military/program/com/sds_2.htm |date=20 September 2016 }} Federation of American Scientists Accessed April 24, 2004

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{{NRO satellites}}

Category:Communications satellites

Category:Hughes Aircraft Company

Category:Military satellites