An Atlas V rocket has successfully launched a classified spy satellite for the United States National Reconnaissance Office (NRO). The satellite, currently known to the public as NRO L-28, or Launch 28, is believed by amateur enthusiasts to be a signals intellegence (SIGINT) spacecraft, known by the codename Trumpet. The Atlas V carrier rocket flew in the 411 configutation, with a 4 metre diameter fairing, one solid rocket motor, and a single-engine Centaur upper stage.

The rocket lifted off from Vandenberg Air Force Base, Space Launch Complex 3 East (SLC-3E), at 10:02 GMT (03:02 local time) this morning. Today's flight marks the thirteenth launch of the Atlas V, and the first Atlas V launch from Vandenberg. It is also the tenth orbital launch of 2008. The satellite entered a Molniya orbit, usually used by the NRO for SIGINT and communications satellites.

The launch was conducted by United Launch Alliance, a joint venture between Lockheed Martin, who designed and built the Atlas V, and Boeing, to provide EELV launches for the US Government. ULA president Michael Gass described the launch as "a proud moment in our company's history". The launch had been delayed by two years, from early 2006, due to a number of factors.

In addition to its reconnaissance payload, the satellite is carrying two small experiments. SBIRS-HEO 2 and TWINS-B. SBIRS is a test article for a missile detection system, slated to launch late this year or early next, and TWINS is a NASA infrared astronomy experiment. They will remain attached to the satellite for the duration of its mission.

Following the separation of the payload fairing, around five minutes after launch, all information on the launch was withheld, however about an hour into the flight, the launch was confirmed to have been successful. ULA will conduct its next launch on Saturday, when a Delta II will orbit a GPS satellite. The next Atlas launch is scheduled for mid-April, with the ICO G1 communication satellite.