{{Short description|American navigation satellite used for GPS}} {{Use American English|date=December 2020}} {{use dmy dates|date=December 2020}} {{Infobox spaceflight | name = USA-94 | names_list = Navstar 2A-13<br/>GPS IIA-13<br/>GPS II-22<br/>GPS SVN-35 | image = | image_caption = | image_size = 290px

| mission_type = Navigation | operator = US Air Force | COSPAR_ID = 1993-054A<ref name="Display"/> | SATCAT = 22779 | mission_duration = 7.5 years (planned)<br/>22.66 years (achieved)

| spacecraft = GPS IIA | spacecraft_type = GPS Block IIA<ref name="GSP"/> | manufacturer = Rockwell International | launch_mass = {{cvt|840|kg}} | dimensions = {{cvt|5.3|m}} of long | power = 710 watts

| launch_date = 30 August 1993, 12:38:00 UTC | launch_rocket = Delta II 7925-9.5<br/>(Delta D222) | launch_site = Cape Canaveral, LC-17B

| entered_service = 1 October 1993 | disposal_type = Graveyard orbit | deactivated = 10 June 2016

| orbit_reference = Geocentric orbit<ref name="Trajectory"/> | orbit_regime = Medium Earth orbit<br/><small>(Semi-synchronous)</small> | orbit_slot = B4 (slot 4 plane B) | orbit_periapsis = {{cvt|20074|km}} | orbit_apoapsis = {{cvt|20221|km}} | orbit_inclination = 54.9° | orbit_period = 716.0 minutes | apsis = gee

| programme = Global Positioning System | previous_mission = USA-92 (GPS IIA-12) | next_mission = USA-96 (GPS IIA-14) }} {{About|the satellite|the association football tournament|1994 FIFA World Cup}} '''USA-94''', also known as '''GPS IIA-13''', '''GPS II-22''' and '''GPS SVN-35''', was an American navigation satellite which formed part of the Global Positioning System. It was the thirteenth of nineteen Block IIA GPS satellites to be launched.

== Background == Global Positioning System (GPS) was developed by the U.S. Department of Defense to provide all-weather round-the-clock navigation capabilities for military ground, sea, and air forces. Since its implementation, GPS has also become an integral asset in numerous civilian applications and industries around the globe, including recreational used (e.g., boating, aircraft, hiking), corporate vehicle fleet tracking, and surveying. GPS employs 24 spacecraft in 20,200&nbsp;km circular orbits inclined at 55.0°. These vehicles are placed in 6 orbit planes with four operational satellites in each plane.<ref name="Display">{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1993-054A|title=Display: Navstar 2A-13 1993-054A|publisher=NASA|date=14 May 2020|access-date=20 December 2020}} {{PD-notice}}</ref>

GPS Block 2 was the operational system, following the demonstration system composed of Block 1 (Navstar 1 - 11) spacecraft. These spacecraft were 3-axis stabilized, nadir pointing using reaction wheels. Dual solar arrays supplied 710 watts of power. They used S-band (SGLS) communications for control and telemetry and Ultra high frequency (UHF) cross-link between spacecraft. The payload consisted of two L-band navigation signals at 1575.42 MHz (L1) and 1227.60&nbsp;MHz (L2). Each spacecraft carried 2 rubidium and 2 Cesium clocks and nuclear detonation detection sensors. Built by Rockwell Space Systems for the U.S. Air force, the spacecraft measured 5.3 m across with solar panels deployed and had a design life of 7.5 years.<ref name="Display"/>

== Launch == USA-94 was launched at 12:38:00 UTC on 30 August 1993, atop a Delta II launch vehicle, flight number D222, flying in the 7925-9.5 configuration.<ref name="LL">{{cite web |url=http://planet4589.org/space/log/launchlog.txt|title=Launch Log|publisher=Jonathan's Space Report|first=Jonathan|last=McDowell|access-date=10 July 2012}}</ref> The launch took place from Launch Complex 17B (LC-17B) at the Cape Canaveral Air Force Station (CCAFS),<ref name="lvdb">{{cite web|url=http://planet4589.org/space/lvdb/list2.html|title=Launch List|publisher=Jonathan's Space Report|work=Launch Vehicle Database|first=Jonathan|last=McDowell|access-date=10 July 2012|archive-date=15 August 2020|archive-url=https://web.archive.org/web/20200815040340/http://planet4589.org/space/lvdb/list2.html|url-status=dead}}</ref> and placed USA-94 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37XFP apogee motor.<ref name="GSP">{{cite web |url=http://space.skyrocket.de/doc_sdat/navstar-2a.htm|title=GPS-2A (Navstar-2A)|first=Gunter|last=Krebs|publisher=Gunter's Space Page|access-date=10 July 2012}}</ref>

== Mission == On 1 October 1993, USA-94 was in an orbit with a perigee of {{cvt|20074|km}}, an apogee of {{cvt|20221|km}}, a period of 716.0 minutes, and 54.9° of inclination to the equator.<ref name="Trajectory">{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1993-054A|title=Trajectory: Navstar 2A-13 1993-054A|publisher=NASA |date=14 May 2020|access-date=20 December 2020}} {{PD-notice}}</ref> It broadcast the PRN 5 signal, and operated in slot 4, and later 5, of plane B of the GPS constellation.<ref>{{cite web |url=http://www.astronautix.com/project/navstar.htm|archive-url=https://web.archive.org/web/20021111162023/http://www.astronautix.com/project/navstar.htm|url-status=dead|archive-date=11 November 2002|title=Navstar|publisher=Encyclopedia Astronautica|first=Mark|last=Wade|access-date=10 July 2012}}</ref> The satellite had a mass of {{cvt|840|kg}} and a design life of 7.5 years.<ref name="GSP"/> It was initially decommissioned on 26 March 2009 and then kept as a residual satellite.<ref name="decomissioned1">{{cite web|url=http://www.navcen.uscg.gov/?Do=gpsShowNanu&num=2009023|title=NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2009023|publisher=United States Coast Guard|access-date=23 June 2016}} {{PD-notice}}</ref> SVN 35 was then recalled to replace SVN 30 in the active constellation on 16 August 2011.<ref name="recomissioned">{{cite web|url=http://www.navcen.uscg.gov/?Do=gpsShowNanu&num=2011062|title=NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2011062|publisher=United States Coast Guard|access-date=23 June 2016}} {{PD-notice}}</ref><ref name="recomissionedstory">{{cite web|url=http://www.insidegnss.com/node/2731|title=2SOPS Takes Over IIF-2, Moves to Replace SVN-30 with Spare|publisher=Inside GNSS|access-date=23 June 2016|archive-date=20 August 2016|archive-url=https://web.archive.org/web/20160820060751/http://www.insidegnss.com/node/2731|url-status=dead}}</ref>

It was then decommissioned again on 1 May 2013, after almost 20 years in orbit,<ref name="decommissioned2">{{cite web|url=http://www.navcen.uscg.gov/?Do=gpsShowNanu&num=2013027|title=NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2013027|publisher=United States Coast Guard|access-date=3 May 2013}} {{PD-notice}}</ref> and finally placed in a disposal orbit approximately 1000&nbsp;km above the operational constellation and deactivated on 10 June 2016.<ref name="disposal">{{cite web|url=http://www.schriever.af.mil/News/Article-Display/Article/805847/obituary-farewell-to-svn-35|archive-url=https://web.archive.org/web/20160622125148/http://www.schriever.af.mil/News/Article-Display/Article/805847/obituary-farewell-to-svn-35|url-status=dead|archive-date=22 June 2016|title=Obituary: Farewell to SVN-35|publisher=United States Air Force|access-date=23 June 2016}} {{PD-notice}}</ref>

== References == {{Portal|Spaceflight}} {{NASA}} {{Reflist|2}}

{{GPS satellites}} {{Orbital launches in 1993}}

Category:Spacecraft launched in 1993 Category:GPS satellites Category:USA satellites