USA-42
{{Short description|American navigation satellite used for GPS}}
{{Use American English|date=December 2020}}
{{Use dmy dates|date=December 2020}}
{{Infobox spaceflight
| name = USA-42
| names_list = Navstar 2-03
GPS II-3
GPS SVN-16
| image =
| image_caption =
| image_size = 290px
| mission_type = Navigation
| operator = U.S. Air Force
| COSPAR_ID = 1989-064A
| SATCAT = 20185
| mission_duration = 7.5 years (planned)
11 years (achieved)
| spacecraft = GPS II
| spacecraft_type = GPS Block II
| manufacturer = Rockwell International
| launch_mass = {{cvt|840|kg}}
| dimensions = 5.3 m (17 ft) of long
| power = 710 watts
| launch_date = 18 August 1989, 05:57:59 UTC
| launch_rocket = Delta II 6925-9.5
(Delta D186)
| launch_site = Cape Canaveral, LC-17A
| launch_contractor = McDonnell Douglas
| entered_service = September 1989
| disposal_type =
| deactivated = 13 October 2000
| orbit_reference = Geocentric orbit
| orbit_regime = Medium Earth orbit
(Semi-synchronous)
| orbit_slot = ?
| orbit_periapsis = {{cvt|20113|km}}
| orbit_apoapsis = {{cvt|20246|km}}
| orbit_inclination = 54.9°
| orbit_period = 717.86 minutes
| apsis = gee
| programme = Global Positioning System
| previous_mission = USA-38 (GPS II-2)
| next_mission = USA-47 (GPS II-4)
}}
USA-42, also known as GPS II-3 and GPS SVN-16, was an American navigation satellite which formed part of the Global Positioning System. It was the third of nine Block II GPS satellites to be launched, which were the first operational GPS satellites to be placed into orbit.
Background
It was part of the 21-satellite Global Positioning System (GPS) Block II series that provides precise position data (accurate to within 16 m) to military and civilian users worldwide. Its signals could be received on devices as small as a telephone. The GPS II satellites, built by Rockwell International for the Air Force Space Systems Division, each have a 7.5-year design life. The Air Force intends to launch a GPS II every 2 to 3 months until the constellation of 21 operational satellite and 3 spares is aloft. The GPS Block II join 7 operational Block 1 satellites.
Launch
USA-42 was launched at 05:57:59 UTC on 18 August 1989, atop a Delta II launch vehicle, flight number D186, flying in the 6925 configuration.{{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}} The launch took place from Launch Complex 17A (LC-17A) at the Cape Canaveral Air Force Station (CCAFS),{{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}} and placed USA-42 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37XFP apogee motor.{{cite web |url=http://space.skyrocket.de/doc_sdat/navstar-2.htm|title=GPS 2 (Navstar 2-03)|first=Gunter|last=Krebs|work=Gunter's Space Page|access-date=10 July 2012}}
Mission
On 19 September 1989, USA-42 was in an orbit with a perigee of {{cvt|20113|km}}, an apogee of {{cvt|20246|km}}, a period of 717.86 minutes, and 54.9° of inclination to the equator.{{cite web|url=http://planet4589.org/space/log/satcat.txt|title=Satellite Catalog|publisher=Jonathan's Space Report|first=Jonathan|last=McDowell |access-date=10 July 2012}} The satellite had a mass of {{cvt|840|kg}}, and generated 710 watts of power.{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1989-064A|title=Display: Navstar 2-03 1989-064A|work=US National Space Science Data Center|publisher=NASA|access-date=10 July 2012}} {{PD-notice}} It had a design life of 7.5 years, and ceased operations on 13 October 2000.
References
{{Portal|Spaceflight}}
{{Reflist|2}}
{{GPS satellites}}
{{Orbital launches in 1989}}