Three classified small satellites for the National Reconnaissance Office fired into orbit from the Eastern Shore of Virginia Tuesday, riding a Northrop Grumman Minotaur 1 booster with a surplus military missile first stage made in 1966, likely the oldest rocket part ever used on a space launch.
The 69-foot-tall (21-meter) Minotaur 1 rocket vaulted off pad 0B at the Mid-Atlantic Spaceport on Wallops Island, Virginia, at 9:35 a.m. EDT (1335 GMT) Tuesday.
Thunderstorms held up work at the Minotaur launch pad early Tuesday, delaying the liftoff more than two-and-a-half hours. Once the bad weather cleared, ground crews returned to the pad to complete launch preparations.
After final arming and pre-flight checkouts, the four-stage, solid-fueled Minotaur 1 rocket rapidly climbed away from the coastal spaceport, which is co-located with NASA’s Wallops Flight Facility, and headed southeast over the Atlantic Ocean.
A thrust vector system steered the rocket as the first stage, originally built in the Cold War for the U.S. Air Force’s Minuteman missile program, burned through its pre-packed propellant to generate more than 200,000 pounds of thrust.
The Minotaur 1 exceeded the speed of sound in less than 30 seconds, darting through scattered clouds as the booster stage exhausted its solid propellant. The Minotaur jettisoned its spent first stage motor casing about a minute into the mission.
The second stage, also taken from the Air Force’s decommissioned Minuteman stockpiles, ignited at the same time and burned for 72 seconds, accelerating the rocket to more than 6,000 mph (nearly 10,000 kilometers per hour).
At that time, NASA’s live webcast of the mission ended at the request of the NRO, the U.S. government’s spy satellite agency. The rest of the launch sequence occurred in secret, but NRO officials later confirmed the flight went according to plan.
Two commercially-produced solid rocket motors built by Northrop Grumman finished the job of placing the three NRO payloads into orbit.
An Orion 50XL third stage ignited nearly two-and-a-half minutes after liftoff. The rocket’s 61-inch-diameter (1.55-meter) titanium payload fairing jettisoned during the third stage burn, once the Minotaur 1 soared above the dense, lower layers of the atmosphere.
After burnout of the third stage, the rocket coasted for several minutes until it reached the proper altitude for ignition of the fourth stage Orion 38 motor, which placed the three NRO satellites into orbit. The payloads separated from the rocket soon after the fourth stage completes its burn.
The NRO has not disclosed the exact purpose, design, or orbit of the satellites. Airspace warning notices suggested the Minotaur 1 rocket targeted an orbit several hundred miles above Earth, at an inclination of about 50 degrees to the equator.
The mission Tuesday was designated NROL-111. Despite the classified payloads, the typically secretive NRO held a pre-launch press conference last week to preview the mission.
“We certainly cannot get into any specifics for national security reasons, but I can tell you that there are three spacecraft that will be launched on this mission,” said Col. Chad Davis, director of the NRO’s office of space launch. “NRO payloads and capabilities, in general, are the nation’s eyes and ears in space, being able to deliver that exquisite intelligence information from space that our warfighters and national decision-makers need.”
NRO satellites collect high-resolution optical and radar imagery of sites around the world, eavesdrop on communications from U.S. adversaries, and help track worldwide military activity.
“NRO is the best in the world at delivering space-based intelligence, surveillance, and reconnaissance to more than 500,000 government users working together to keep America safe,” said Christopher Scolese, director of the NRO, in a post-launch statement. “NROL-111 is the 16th payload we put on orbit in 18 months to advance our mission of providing critical information to every member of the intelligence community, two dozen domestic agencies, our nation’s military, lawmakers, and decision makers.”
In 2016, the Space Force’s Space and Missile Systems Center, then part of the Air Force, selected a Minotaur 1 rocket for the NROL-111 mission. The launch contract awarded to Orbital ATK, since acquired by Northrop Grumman, was valued at $29.2 million.
The launch Tuesday marked the 28th flight of a Minotaur rocket since 2000, including suborbital missions. It was the 18th orbital launch of a Minotaur rocket, and the 12th use of the Minotaur 1 configuration, which is capable of placing a payload of up to 1,278 pounds (580 kilograms) into low Earth orbit.
The Minotaur 1 is based on leftover solid-fueled motors from the U.S. Air Force’s Minuteman missile program. Designers added two Orion solid rocket motors on top of the lower two stages of a Minuteman missile to turn the bomb carriers into satellite launchers.
The Minotaur 1 rocket’s M55A1 first stage motor was cast with solid propellant in 1966 by Thiokol, now part of Northrop Grumman. The SR19 second stage motor, produced by Aerojet, was filled with its solid propellant in 1983, according to a Northrop Grumman spokesperson.
The age of the first stage means it is likely the oldest rocket motor ever used on a space launch.
After going on alert with nuclear warheads in silos during the Cold War, the Minuteman missile motors were stored at Hill Air Force Base, Utah, and refurbished there before shipping out for launch preparations.
Military teams test-fired Minuteman motors with similar ages in 2019 and 2020, and engineers verified good performance in both stages.
“We are using these decommissioned assets, taxpayer-funded assets, and we’re taking them and we’re able to launch government-sponsored payloads, which to me is actually one of the coolest things about our Minotaur 1 rocket,” said Kelly Fitzpatrick, a Northrop Grumman senior guidance, navigation and control engineer.
Northrop Grumman also launches the Minotaur 4 rocket family using more powerful surplus Peacekeeper missile motors.
Tuesday’s mission was the eighth Minotaur rocket to launch from the Mid-Atlantic Regional Spaceport in Virginia. Minotaur missions have also launched from Vandenberg Space Force Base in California, the Pacific Spaceport Complex in Alaska, and Cape Canaveral Space Force Station in Florida.
The NROL-111 mission was the second launch in two days for Northrop Grumman’s rocket program.
The company’s air-launched Pegasus XL rocket fired into orbit Sunday off the coast of California with a small Space Force satellite named Odyssey. The spacecraft was developed in less than a year, and the Space Force conceived the mission as a demonstration for a “tactically responsive launch” capability.
Military officials informed Northrop Grumman of the target launch date and the mission’s orbital parameters just 21 days ahead of time. Northrop Grumman configured a Pegasus rocket already in its inventory to launch the Odyssey space surveillance satellite.
“It just shows the depth and breadth of Northrop Grumman’s capabilities that we have fairly independent teams to be able to get these two launches off in two days on opposite coasts,” said Kurt Eberly, head of the company’s launch vehicles division.
“These launches are both for the U.S. Space Force, so when they want to launch, and when the Space Force’s customer — the NRO — wants to launch, we try to be there on the day that they want,” Eberly said.
Northrop Grumman’s orbital-class rockets, which also include the Antares launcher used for space station resupply missions, have a relatively low flight rate. The launch Sunday was the first flight of a Pegasus rocket since 2019, and Antares rockets typically launch about twice per year.
But the company also launches suborbital rockets on tests of the U.S. military’s missile defense system. Eberly said Northrop Grumman plans to launch 28 rockets in 2021, and they all use the same common avionics package, from small target vehicles to the medium-class Antares rocket.
“Most of them you’re not really going to hear about,” he said. “They’re target launches for various parts of the military, but nonetheless each of those is a rocket in and of itself.”
Northrop Grumman has no more Pegasus launches in its backlog, but the Space Force and the NRO have purchased at least one more Minotaur flight to deliver another classified payload to orbit.
That mission, known as NROL-174, will use a Minotaur 4 rocket, the larger Minotaur variant. It is scheduled for launch in 2023, Eberly said. A launch site for the NROL-174 mission has not been confirmed.
Northrop Grumman’s next orbital launch is scheduled in August, when an Antares rocket will take off from Virginia with the next Cygnus cargo ship for the International Space Station.
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