Delta IV Heavy
United Launch Alliance’s Delta IV Heavy is a heavy-lift launch vehicle, the largest type of the Delta IV family and one of the world’s most powerful rockets. The Delta IV Heavy configuration is comprised of a common booster core (CBC), a cryogenic upper stage and a 5-meter diameter payload fairing (PLF). The Delta IV Heavy employs two additional CBCs as liquid rocket boosters to augment the first-stage CBC. The Delta IV Heavy can lift 28,370 kg (62,540 lbs) to low Earth orbit and 13,810 kg (30,440 lbs) to geostationary transfer orbit. It is an all liquid-fueled rocket, consisting of an upper stage, one main booster and two strap-on boosters.
Payload Fairing (PLF)
The PLF encapsulates the spacecraft to protect it from the launch environment on ascent. The 19.8 m (65 ft) long PLF makes the vehicle’s height approximately 71.5 m (235 ft).
Delta Cryogenic Second Stage (DCSS)
The DCSS is a cryogenic liquid hydrogen/liquid oxygen fueled vehicle, with a single RL10C-2-1 engine that produces 24,750 lbf (110 kN) of thrust.
The Delta IV booster propulsion is provided by three liquid hydrogen and liquid oxygen-burning RS-68A engines. Each RS-68A engine produces 705,250 lbf (3,137 kN) of thrust for a combined total liftoff thrust of more than 2.1 million lbf (9.4 mega-Newtons).
Space Launch Complex 37 (SLC-37)
NROL-68 will launch from Space Launch Complex-37 (SLC-37) at Cape Canaveral Space Force Station, Florida. SLC-37 was built in 1962 for earlier programs and retrofitted in 1998 to launch Delta IV vehicles. The first Delta IV Heavy launch from SLC-37 was in December 2005. NROL-68 will be the sixth and penultimate Delta IV Heavy launch from Cape Canaveral.