Triangulum constellation dating ariane
As is usual for an NRO mission, details of the NROL-37 payload are kept classified by the US Government, as are specifics of the Delta IV’s mission profile.Typically launch broadcasts and official coverage of NRO missions will end shortly after separation of the payload fairing from around the satellite.The Delta IV Heavy is capable of placing a payload of 6,750 kilograms (14,900 lb) directly into geosynchronous orbit or upwards of 14,000 kg (31,000 lb) into a geosynchronous transfer orbit.
Due to performance enhancements introduced to the Delta IV ahead of the NROL-15 launch, combined with unconfirmed reports that the increase in the rocket’s performance was necessary for the mission, it has been speculated that NROL-15 may be the first satellite of a third-generation Orion constellation. The modifications made ahead of NROL-15 – including RS-68A engines on the first stage and boosters in place of the earlier RS-68 – are now standard across the Delta IV fleet including Delta 374, which will make the launch.
The Delta IV’s second stage, a five-metre Delta Cryogenic Second Stage (DCSS), is powered by a single RL10B-2 engine also burning liquid hydrogen and liquid oxygen.
The engine has an extendible nozzle which will be deployed following first stage separation; the RL10 will ignite about 13.5 seconds after staging has been completed.
All three ignited five and a half seconds before liftoff, building up to full thrust by T-0, when launch occurred.
After lifting off, the rocket pitched and yawed to attain its planned easterly trajectory.
The first two satellites were deployed from Space Shuttle Discovery during the 19 STS-51C and STS-33 missions, with the aid of Inertial Upper Stages.