I happened to think about the Parker Solar Probe scheduled to be launched between 31 July and 19 August 2018. This launch also uses the Delta IV the same family of lift vehicles as the NROL – 47 launch today uses although the Parker Solar Probe will use the Delta IV heavy.
Actually the Delta IV is rather versatile, coming in different lift strengths, the NROL-47 uses a Delta IV Medium (5,2) version that can put 10,220 kg / 22,500 lbs into Low Earth Orbit, where as the Delta IV Heavy can put 25,980 kg / 57,300 lbs into that same LEO.
There will be more about Parker Solar Probe coming in time and what a mission this will be. The probe will come within 5.95 million km / 3.7 million miles from the surface of the Sun at closest approach. Yes it will get HOT, the sun shade will reach an estimated 1,377 deg C / 2,500 deg F. The spacecraft will also be moving VERY fast at that point whizzing by at an astounding 700,000 kmh / 438,000 mph!!