USA-239

{{Short description|American navigation satellite used for GPS}}

{{Infobox spaceflight

| name = USA-239

| image = Navstar-2F.jpg

| image_caption = A Block IIF GPS satellite

| insignia =

| mission_type = Navigation

| operator = US Air Force

| COSPAR_ID = 2012-053A{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2012-053A|title=Navstar 67|publisher=US National Space Science Data Center|access-date=18 February 2014}}

| SATCAT = 38833

| mission_duration = 12 years (planned)

| spacecraft = GPS SVN-65 (IIF-3)

| spacecraft_type = GPS Block IIF

| manufacturer = Boeing

| launch_mass = {{convert|1630|kg}}

| dimensions =

| power =

| launch_date = {{start-date|4 October 2012, 12:10|timezone=yes}} UTC

| launch_rocket = {{nowrap|Delta IV-M+(4,2),}} D361

| launch_site = Cape Canaveral SLC-37B

| launch_contractor = ULA

| entered_service =

| disposal_type =

| deactivated =

| orbit_epoch =

| orbit_reference = Geocentric

| orbit_regime = Medium Earth
(Semi-synchronous)

| orbit_apoapsis = {{convert|20231|km|sp=us}}

| orbit_periapsis = {{convert|20132|km|sp=us}}

| orbit_inclination = 54.87 degrees

| orbit_period = 717.96 minutes

| apsis = gee

}}

USA-239, also known as GPS IIF-3, GPS SVN-65, and Navstar-67 is an American navigation satellite which forms part of the Global Positioning System. It was the third of twelve Block IIF satellites to be launched.

Built by Boeing and launched by United Launch Alliance, USA-239 was launched at 12:10 UTC on 4 October 2012, atop a Delta IV carrier rocket, flight number D361, flying in the Medium+(4,2) configuration.{{cite web|url=http://planet4589.org/space/log/launchlog.txt|title=Launch Log|publisher=Jonathan's Space Page|first=Jonathan|last=McDowell|access-date=18 February 2014}} The launch took place from Space Launch Complex 37B at the Cape Canaveral Air Force Station,{{cite web|url=http://planet4589.org/space/lvdb/list2.html|title=Launch List|publisher=Jonathan's Space Page|work=Launch Vehicle Database|first=Jonathan|last=McDowell|access-date=18 February 2014|archive-date=15 August 2020|archive-url=https://web.archive.org/web/20200815040340/http://planet4589.org/space/lvdb/list2.html|url-status=dead}} and placed USA-239 directly into medium Earth orbit. The rocket's second stage failed to provide the expected full thrust in all of its three burns due to a leak above the narrow throat portion of the thrust chamber, however the stage had enough propellant margins to put the satellite in the correct orbit.{{cite web|url=http://spaceflightnow.com/delta/d361/investigation.html|title=Investigation finds Delta 4 rocket engine issue|publisher=Spaceflight Now|first=Justin|last=Ray|date=9 Dec 2012|access-date=18 February 2014}}

As of 18 February 2014, USA-239 was in an orbit with a perigee of {{convert|20231|km|sp=us}}, an apogee of {{convert|20132|km|sp=us}}, a period of 717.96 minutes, and 54.87 degrees of inclination to the equator.{{cite web|url=http://planet4589.org/space/log/satcat.txt|title=Satellite Catalog|publisher=Jonathan's Space Page|first=Jonathan|last=McDowell|access-date=18 February 2014}} It is used to broadcast the PRN 24 signal, and operates in slot 1 of plane A of the GPS constellation. The satellite has a design life of 15 years and a mass of {{convert|1630|kg}}.

{{cite web|url=http://space.skyrocket.de/doc_sdat/navstar-2f.htm|title=GPS-2F (Navstar-2F)|first=Gunter|last=Krebs|work=Gunter's Space Page|access-date=18 February 2014}} As of 2019 it remains in service.