With an orbital inclination of 73.6 degrees, its orbit is lower than the other operational satellites, meaning that it does not pass as close to the Earth’s poles. Deployed by the NROL-71 mission in January 2019, it was the last-but-one KH-11 to launch prior to NROL-91. Up until now, the only KH-11 not operated in Sun-synchronous orbit has been USA-290. Most have operated in a Sun-synchronous orbit (SSO) - a particular type of low, near-polar, orbit that allows them to cover most of the Earth’s surface, ensuring they pass over each point at the same local solar time every day, ensuring consistent lighting conditions. They are rumored to resemble the Hubble Space Telescope but pointed toward the Earth, rather than out into space. The Crystal satellites are believed to give the NRO its highest-resolution pictures of the Earth’s surface. Failures in the procurement of the successor Future Imagery Architecture (FIA) saw additional Crystal spacecraft constructed, with the first bearing a conspicuous phoenix on its mission patch.ĭeclassified image taken by a KH-11 satellite, showing Iran’s Semnan launch site (Credit: NRO/US Government) The fourteenth KH-11, USA-186, was the payload for the final Titan IV launch and was at the time also expected to be the last Crystal satellite. Previous satellites had flown aboard Titan rockets, initially the Titan III(23)D and Titan III(34)D, and later the Titan IV. NROL-91 will be the nineteenth Crystal satellite to be launched, and the fifth to fly aboard a Delta IV. Since then, the satellites have undergone further upgrades, with several different blocks of spacecraft identified. When it was introduced in 1976, the KH-11 did away with these, instead downlinking images electronically.
#Nasa space shuttle final launch series
Earlier members of this series used small capsules to return photographic film to Earth for development. The satellite launched by the NROL-91 mission is expected to take on the designation USA-337, the next available number in this sequence.Ĭrystal, also known as KH-11, is the successor to a long line of Keyhole reconnaissance satellites that the NRO has operated since the 1960s. The NRO does not acknowledge the names or types of satellites it operates instead, they are assigned an NROL designation prior to launch and a numerical USA designation upon reaching orbit. Those signals intelligence satellites are typically launched by smaller rockets, so the combination of rocket and launch site suggests that NROL-91 will deploy one of the agency’s large imaging satellites, part of a program identified in previously leaked documents as Crystal. From its location on the West Coast, Vandenberg is an ideal launch site for low Earth orbit (LEO) reconnaissance satellites operating in polar and near-polar orbits, as well as some signals intelligence satellites in elliptical orbits. Delta IV Heavy missions carry satellites that have too great a mass for the most powerful Atlas V configurations to place into their destined orbits, indicating the satellite is very heavy, bound for a high orbit, or both. While the National Reconnaissance Office (NRO) keeps details of its satellites classified, the use of a Delta IV Heavy and the fact the launch is taking place from Vandenberg speak volumes. Saturday’s mission, NROL-91, is the final Delta IV launch from California’s Vandenberg Space Force Base, with the rocket’s remaining missions to be executed from the East Coast at Cape Canaveral. Delta IV Heavy, with its significantly higher payload capacity, has been kept in service to carry out a handful of national security launches that cannot be performed by Atlas V. One of the first steps in that transition was winding down Delta IV operations, with the last Delta IV Medium+ launch taking place in 2019. Delta IV, alongside its former competitor-turned-stablemate Atlas V, is now being phased out as a new generation of launchers prepare to take their place. Liftoff of the NRO Launch 91 (NROL-91) mission from Space Launch Complex 6 - at the Vandenberg Space Force Base in California - took place at 3:25 PM PDT (22:25 UTC).ĭelta IV Heavy is the most powerful version of the Delta IV, one of two rockets developed under the US Air Force’s Evolved Expendable Launch Vehicle (EELV) program to meet the US Government’s launch needs in the early 21st century. United Launch Alliance’s (ULA) Delta IV Heavy rocket made its last West Coast launch on Saturday, carrying out a mission for the National Reconnaissance Office, as it moves one flight closer to retirement.
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