Template:Infobox spaceflight USA-203, also known as GPS IIR-20(M), GPS IIRM-7 and GPS SVN-49, was an American navigation satellite which was intended to become part of the Global Positioning System. It was the sixth of seven Block IIRM satellites to be launched, and the twentieth of twenty one Block IIR satellites overall. It was built by Lockheed Martin, using the AS-4000 satellite bus, and had a mass of 2,032 kilograms (Template:Convert/round lb).[1]

USA-203 was launched at 08:34 UTC on 24 March 2009, atop a Delta II carrier rocket, flight number D340, flying in the 7925-9.5 configuration.[2] The launch took place from Space Launch Complex 17A at the Cape Canaveral Air Force Station,[3] and placed USA-203 into a transfer orbit. The satellite raised itself into medium Earth orbit using a Star-37FM apogee motor.[1]

USA-203 is located in an orbit with a perigee of 20,045 kilometres (Template:Convert/round mi), an apogee of 20,335 kilometres (Template:Convert/round mi), a period of 718 minutes, and 55.8 degrees of inclination to the equator.[4] It was intended to operate in slot 2 of plane B of the GPS constellation, replacing USA-128,[5] and to broadcast signal PRN-01.[6] During on-orbit testing an anomaly was discovered with the signals it was broadcasting, which prevented its operational use. It was decommissioned on 6 May 2011, two years into its ten-year design life.

In addition to its operational navigation signals, USA-203 was also equipped to broadcast a demonstration of the L5 signal which would be introduced with the GPS Block IIF series. The satellite was able to broadcast this signal correctly, but it was discovered that a filter used to produce the L5 signal was causing the disruption to its other frequencies.[6]


Launch of USA-203


  1. 1.0 1.1 Krebs, Gunter. "GPS-2RM (Navstar-2RM)". Gunter's Space Page. Retrieved 11 July 2012. 
  2. McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 11 July 2012. 
  3. McDowell, Jonathan. "Launch List". Launch Vehicle Database. Jonathan's Space Page. Retrieved 11 July 2012. 
  4. "NAVSTAR 63 (USA 203)". n2yo. Archived from the original on 11 July 2012. Retrieved 11 July 2012. 
  5. Ray, Justin (24 March 2009). "Delta 2 rocket delivers another GPS satellite to orbit". Spaceflight Now. Retrieved 11 July 2012. 
  6. 6.0 6.1 Goldstein, David. "Request for Feedback on GPS IIR-20 (SVN-49) Mitigation Options". US Air Force. Retrieved 11 July 2012. 
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