Delta-4 Heavy

Delta 4-Heavy on the pad prior to NROL-37. Credit: ULA

Liftoff of NROL-37. Credit: Alex Polimeni/Spaceflight Now

Descriptions:

• The Delta 4-Heavy is capable of delivering 14,900 pounds of payload into a circular geosynchronous orbit, the most of any rocket flying today. The vehicle´s maximum operation time is eight hours.
  This was the fifth time an operational Delta 4-Heavy reached geosynchronous orbit, once for the Air Force and now four missions for the NRO.
• Observers say these satellites are the brightest ones seen in geosynchronous orbit and the NRO calls them the largest in space.
• This was the 374th Delta rocket launch since 1960 and the 32nd Delta 4 since debuting in 2002. The vehicle has flown 17 Air Force flights, 10 for the National Reconnaissance Office and five commercial missions.
  For the NRO, is was the 44th flight since the agency began acknowledging and publicly claiming its launches in 1996 and the 21st from the Cape.