Launch Vehicle
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.
The Delta IV was created to fulfill the requirements of the United States Air Force’s Evolved Expendable Launch Vehicle (EELV) program. The inaugural launch of the Delta IV occurred in 2002. NROL-70 is the last ever launch of ULA’s Delta IV of either medium or heavy variants. NROL-70 builds upon a long legacy of NRO Delta IV Heavy launches at Cape Canaveral dating back to 2009.
Payload Fairing (PLF)
The PLF encapsulates the spacecraft to protect it from the launch environment on ascent. The 19.8m (63-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 110.1 kilo-Newtons (24,750 lbs) of thrust.
Boosters
The Delta IV booster propulsion is provided by three liquid hydrogen and liquid oxygen-burning RS-68A engines. Each RS-68A engine produces 312.3 kilo-Newtons (705,250 lbs) of thrust for a combined total liftoff thrust of more than 2.1 million pounds.
Site Info
NROL-70 has launched from Space Launch Complex-37 (SLC-37) at Cape Canaveral Space Force Station, Florida. SLC-37 was built in 1962 as Complex 37 to support the Saturn 1 and Saturn 1B programs. Between 1964 and 1968, it supported a total of eight unmanned Saturn launches but was eventually mothballed in 1971. In 1998, Boeing retrofitted it to launch the then-new Delta IV. The first Delta IV Heavy launch from SLC-37 was in December 2004. NROL-70 will be the eleventh Delta IV Heavy launch from Cape Canaveral, and the final Delta IV heavy launch in history.