NROL-71 kicks off ULA’s 2019 launch manifest

Patrick Attwell

LOMPOC, Calif. — United Launch Alliance (ULA) successfully completed its first flight of 2019. Today’s launch utilized the largest rocket in the Colorado-based company’s arsenal to send a classified payload into space. In doing so the company finally managed to move past a saga of delays.

ULA’s Delta IV Heavy rocket had been selected to send the classified NROL-71 payload to orbit from Vandenberg Air Force Base’s Space Launch Complex 6 (SLC-6) at 11:10 a.m. PST (2:10 p.m. EST), Jan. 19, 2019. The flight had been slated to get underway five minutes earlier but was pushed back to allow the team to complete final items before entering terminal count. That tiny adjustment marked the final slip for the oft-delayed mission.

NROL-71 had been slated to get underway on Sept. 26, Dec. 7, 8, 18, 19, 20 and 30 (in 2018). On Jan. 5, 2019 ULA stated that the launch date was “under review.”

“We understand that this is a high-priority mission for the nation’s warfighters and we take our commitment to safety and mission assurance seriously,”Gary Wentz, vice president of Government and Commercial programs said via a ULA-issued statement.

NROL-71 was ULA’s 28th flight for the National Reconnaissance Office (NRO) and the 38th launch of a Delta IV rocket (today’s flight marked only the 11th use of the rocket in its “Heavy” configuration). The Delta IV first took to the skies on Nov. 20 of 2002.

The NRO is the U.S. government’s agency in charge of designing, building, launching and maintaining the U.S. fleet of intelligence satellites. Formed in 1961, the existence of the NRO was a tightly kept secret.

Until 1973, the NRO’s very existence wasn’t public knowledge (and even then it was revealed by accident). It was declassified in September of 1992. Now the NRO has its own Facebook page. NROL-71 is the agency’s 52nd known payload that has been launched since 1996.

Due to NROL-71’s classified nature, little is known about what was actually launched, but it is believed to be an electro-optical imaging reconnaissance satellite, operating from an elliptical polar orbit of roughly 160 by 620 miles (260 by 1,000 kilometers).

The NROL-71 mission marked the first flight of the 233-foot (71-meter) Heavy variant of the Delta IV rocket from Vandenberg in more than five years. The vehicle consists of three Common Booster Cores (CBCs), a 16 foot (5-meter) diameter payload fairing and a Delta Cryogenic Second Stage. Each of the CBCs is powered by an RS-68A, manufactured by Aerojet Rocketdyne. The rocket’s second stage is propelled by an RL-10 engine.

Each RS-68A engine provided an estimated 702,000 pounds of thrust during the initial phase of the flight. After staging, an RL10B-2 granted some 24,750 pounds of thrust to send the Delta IV Heavy’s upper stage with the payload into orbit.

An old foe appeared to be raising its head shortly before the opening of today’s launch window — high winds. As ULA’s CEO and President Tory Bruno noted in tweets prior to liftoff: “Wind is creeping up. Everybody think calm thoughts.”

As things improved, Bruno appeared more optimistic — something that paid off later on in the day: “Board is green, wind is high but better.”

At 90 seconds before launch a ULA commentator stated something that the launch team had waited a long time to hear: all key elements were ready to support the flight. Once the 90 seconds had elapsed, flames flickered up from the base of the rocket, heralding the start of the flight.

Once the rocket lifted off the pad, it began a short vertical rise before pitching over on a southward trajectory out over the Pacific Ocean. It reached Mach 1 — the speed of sound — about a minute-and-a-half after liftoff.

Around this point in the mission the Delta IV Heavy was burning about 5,000 pounds (2,268 kilograms) of fuel per second.

Four minutes, 10 seconds after it had taken flight, the two side-mounted CBCs depleted their fuel and fell away. Nearly two minutes later, the center core finished its part of the mission and separated from the upper stage, which activated its lone engine about at 5 minutes, 55 seconds after launch for a burn that was slated to last about 12 minutes and six seconds.

Because this was a classified mission, ULA coverage of the launch concluded at payload fairing separation, which occurred 6 minutes, 6 seconds after leaving the pad.

ULA’s next planned flight is a launch of another Delta IV, this one in its Medium+ (5,4) configuration. Its payload will be the 10th Wideband Global SATCOM spacecraft for the U.S. Air Force. At present, that mission is scheduled to launch on March 13, 2019, from Cape Canaveral Air Force Station’s Space Launch Complex 37B in Florida.