ORION-9 satellite created for National Reconnaissance Office will be launched utilizing DELTA IV HEAVY. Mission planned launch site is SLC-37, Cape Canaveral AFS.
As usual National Reconnaissance Office does not disappoint and gives rise to speculating. According some sources this time, planned payload will be Orion satellite. It would be ninth from Orion series so scheduled rocket is not surprise. In mission scheduled on 27th April 2016 one we know for sure - ULA will utilize Delta IV Heavy rocket. These satellites are operating since 1995 and have been launched using Titan or Delta rockets. It is known, that Orion were developed to meet demands of NRO and CIA as a new SIGINT satellite (SIGINT refers to gathering intelligence signals from space, for example telemetry data of rockets). It is heavy satellite with weight around 5200 kg and large (about 100 m after deploying) antennas for receiving radio signals. Manufacturer is not known, but other SIGINT satellites were made by TRW.
Delta IV rocket is soon be retired. ULA is going to keep only Delta IV Heavy operational after 2018. Rest of launches will be moved to Atlas V. Delta IV in its largest version offers 5 m long payload fairings and weight of GTO missions cargo up to 14220 kg. Heavy version is equipped with two more CBC (Common Booster Core) comparing to Medium. It means that in version Heavy, rocket is equipped with three identical first stages (this is clearly visible in the picture). Each of them is powered with one RS-68 engine fueled with liquid oxygen and liquid hydrogen. Each from CBC has thrust at 3140 kN and weighs 224600 kg. After ignition and start CBC from left and right is separating earlier then center. Second stage is generally common with Medium version. Its name is DCSS (Delta Cryogenic Second Stage) and is powered with RL-110-B-2 engine with thrust at 110 kN. Difference is in interstage - in Medium fairing is narrowing from 5m to 4m in diameter; in Heavy fairing is cylindrical (diameter at 5m).
We can assume that because of dimensions of Orion on previously launches, TITAN rocket was utilized. Now Delta in Heavy version offers similar payload capacity dimensions (especially with 5 m long fairing) and really "Heavy" costs. For commercial market, Delta is not competitive (withdrawal of this rocket from civilian market was decided by Boeing in 2003) - cost of the rocket is around $400 million. Atlas V costs around $170 million and still is one of more expensive solution on the market. United Launch Alliance decision of keeping Delta Heavy after 2018 it is perhaps dictated by NRO and necessity of providing dependable launch solution for extra-long payloads (for extra money of course).