WASHINGTON — A Northrop Grumman Minotaur 4 solid propellant rocket launched the NROL-129 mission for the National Reconnaissance Office on July 15 at 9:46 a.m. Eastern from NASA’s Wallops Flight Facility in Virginia.
The launch originally scheduled for 9:00 a.m. was delayed by the presence of fishing boats in restricted waters offshore that had to be cleared from the area.
The classified NROL-129 mission carried four remote sensing payloads.
This was the Minotaur 4’s first flight from the Mid-Atlantic Regional Spaceport at NASA’s Wallops Island Facility. It was the NRO’s 54th launch since 1996 and its first launch on a Minotaur 4, a four-stage vehicle made with three government-furnished solid rocket motors from decommissioned Peacekeeper intercontinental ballistic missiles. The upper stage is a Northrop Grumman Orion solid rocket.
The Minotaur 4 debuted in 2010. It can launch payloads of up to 1,730 kilograms to low Earth orbit.
The U.S. Space Force Space and Missile Systems Center acquired the launch through the Rocket Systems Launch Program.
The rocket motors used to build the vehicle that flew on Wednesday were cast between 1988 and 1990, Kurt Eberly, Northrop Grumman’s director of launch vehicles, told SpaceNews.
The U.S. Air Force stores and maintains surplus rocket motors in silos at Hill Air Force Base, Utah. They are shipped to launch locations where Northrop Grumman assembles the rockets.
“These motors remain very stable,” said Eberly. “We keep them in a good environment.”
Eberly said the NRO has booked two more Minotaur launches scheduled for next year, NROL-111 and NROL-174. The NRO is viewed as an attractive customer for Northrop Grumman’s solid rockets, said Eberly. The vehicles can be assembled and launched on short notice which fits the agency’s need for “rapid response,” he said.
The Minotaur 4 can launch from austere sites. Because it’s all solid motors it doesn’t require a liquid fuel farm next to the pad. The vehicle has launched missions from Wallops Island; Vandenberg Air Force, California; Kodiak Island, Alaska and from Cape Canaveral Air Force Station, Florida.
“We think there’s a real niche for the Minotaur and Pegasus solid rockets for DoD and intelligence agency customers,” said Eberly. The Pegasus is Northrop Grumman’s air-launched rocket.