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Receiving a boost from a modified decades-old Peacekeeper missile originally built for nuclear war, a U.S. military space surveillance satellite streaked into space early Saturday from Cape Canaveral to help the Air Force track threats and debris in orbit.

Running nearly three hours late after storms delayed final launch preparations, the eight-story Minotaur 4 rocket blasted off from Cape Canaveral’s Complex 46 launch pad at 2:04 a.m. EDT (0604 GMT).

The booster quickly climbed through a deck of clouds, exceeded the speed of sound within 20 seconds, and headed toward orbit on top of a half-million pounds of thrust.

Heading east over the Atlantic Ocean, three solid-fueled rocket motors stacked atop one another fired in quick succession to send the Minotaur 4 rocket and its payload, the military’s ORS-5 satellite tracking craft, into space.

The Minotaur’s lower three stages were repurposed from the Air Force’s stockpile of retired Peacekeeper nuclear missile. The modified Peacekeeper motors launched Saturday were originally built in the 1980s and put on alert in a missile silo ready to hurl nuclear warheads to distant targets.

The Air Force phased out the Peacekeeper in 2005 in favor of the Minuteman missile, leaving the leftover rocket stages available for satellite launches.

Two commercial Orion 38 rocket motors built by Orbital ATK did the extra lifting needed to reach a unique orbit hugging the equator, an unusual perch required for the ORS-5 satellite to conduct its space surveillance mission.

Two Prometheus CubeSat secondary payloads for Los Alamos National Laboratory and a CubeSat for the Defense Advanced Research Projects Agency, or DARPA, deployed from the rocket after an on-target fourth stage burn that reached a preliminary parking orbit ranging in altitude between 248 and 372 miles (400 to 600 kilometers).

The fourth stage firing put the rocket in an orbit tilted around 24.5 degrees to the equator. A final rocket burn redirected the ORS-5 satellite into an orbit that stays above the equator.

The military’s ORS-5 satellite, roughly the size of a coffee table, deployed from the Minotaur upper stage around 28-and-a-half minutes after liftoff.

Orbital ATK, the Minotaur 4 rocket’s commercial operator, confirmed the upper stage injected the ORS-5 payload into an orbit between 372 and 375 miles (599 to 604 kilometers), very near prelaunch predictions.

Ground controllers contacted the ORS-5 satellite a few minutes after separation from the rocket, verifying the spacecraft was healthy and stable to begin its three-year mission.

Orbital ATK declared the launch a success, giving the Minotaur rocket family a 16-for-16 record in satellite deployment missions since 2000. Counting suborbital Minotaur flights, the program has launched 26 times.

Saturday’s launch was the first time a Minotaur rocket took off from Cape Canaveral. All Previous flights were based off launch pads in California, Virginia and Alaska.

“This was our first Minotaur launch from Cape Canaveral Air Force Station, demonstrating the rocket’s capability to launch from all four major U.S. spaceports,” said Rich Straka, vice president and general manager of Orbital ATK’s launch vehicles division. “With a perfect track record of 26 successful launches, the Minotaur family has proven to be a valuable and reliable asset for the Department of Defense.”

The $87.5 million ORS-5 mission is the latest in a line of relatively low-cost military projects managed by the military’s Operationally Responsive Space office at Kirtland Air Force Base, New Mexico. Previous ORS missions have tested plug-and-play satellite technology, deployed experimental imaging and data relay satellites, and demonstrated an autonomous rocket destruct mechanism now used on commercial launchers.

“The capabilities ORS-5 brings to the nation are ushering in a new era of faster, cheaper satellite development,” said Lt. Gen. John Thompson, commander of the Air Force Space and Missile Systems Center. “ORS-5 will deliver global, persistent, optical tracking of satellites in geosynchronous orbit, enabling the nation to have increased global situational awareness of space objects.”

Air Force Col. Shahnaz Punjani, director of the ORS office, compared the ORS-5 satellite’s function to the A-10 attack jet, an aircraft that carries a powerful armor-piercing cannon.

“When people talk about the A-10 aircraft, (they say) it’s really a gun with an airplane wrapped around it,” Punjani said. “In this case, the ORS-5 satellite is essentially a telescope in low Earth orbit with a spacecraft wrapped around it, looking at the geosynchronous belt.”

Another way to look at it is to compare the ORS-5 satellite to an airport radar, said Grant Stokes, head of the space systems and technology division of the Massachusetts Institute of Technology’s Lincoln Laboratory, where the spacecraft was developed and manufactured.

“It’s sort of analogous to a surveillance radar at an airport, which goes around and around, surveilling the domain,” Stokes told reporters in a prelaunch briefing Thursday. “Once per orbit, what ORS-5 will do is scan the GEO (geosynchronous) belt and keep track, essentially, of all the items there.

“The GEO belt is particularly important,” Stokes said. “There’s a huge collection of satellites there, and a tremendous amount of economic value in that special orbit, so it is one that generally we want to keep fairly good tabs on what’s there and where things are.”

Satellites in geosynchronous orbit nearly 22,300 miles (35,800 kilometers) above the equator fly around Earth at the same rate the planet rotates. The effect at that altitude keeps satellites over the same geographic position at all times.

Designed for a three-year mission, ORS-5 should feed military officials data on how objects are moving around geosynchronous orbit. After identifying which objects might be threats, the Air Force could task the more capable SBSS Block 10 satellite to take better pictures, or send one of the military’s four close-up inspection satellites in geosynchronous orbit to take a closer look, according to Lt. Col. Heather Bogstie, ORS-5 program manager.

The data output from ORS-5 “gives you dots on a screen,” Stokes said.

“We very carefully measure how bright they are, but it does not resolve in any way,” he said. “It’s a dot at a distance of something like 40,000 kilometers (nearly 25,000 miles).”

Punjani said the ORS-5 satellite is a “change detection agent” to collect imagery of broad swaths of space. In keeping with the ORS program’s low-cost ethos, the ORS-5 mission was conceived to meet minimum standards required by the military’s space surveillance division, without the bells and whistles on more expensive spacecraft.

The SBSS Block 10 satellite launched in September 2010 cost more than $800 million, around 10 times more than ORS-5.

SBSS Block 10 will exceed its seven-year design life later this year, and a full-up replacement satellite is not expected to launch until at least 2021. ORS-5 will fill the potential gap in tracking coverage.

“When you look at how ORS builds our satellites, we’re going to go small,” Punjani said. “We’re going to go to threshold requirements, and then we’re going to hold to those requirements and not change those requirements throughout the life cycle, in order to ensure we rapidly acquire these programs. This program was done within three years, compared to other satellite programs that have a five-to-ten year life cycle.”

The Air Force said the ORS-5 satellite itself cost around $49 million. Another $27.2 million went toward purchasing the Minotaur 4 launch from Orbital ATK, the rocket’s commercial operator, and ground systems cost $11.3 million.

The military needed a dedicated rocket for the ORS-5 mission because of its unique orbit directly over the equator. That type of orbit required the Air Force and Orbital ATK to base the launch from Cape Canaveral instead of from an already-used Minotaur pad at Wallops Island, Virginia.

Officials looked at several launch options, including building a temporary Minotaur launch pad at Kwajalein Atoll in the Marshall Islands, or at the European-run Guiana Space Center in South America.

The cheapest and least risky option ended up being an uprated Minotaur 4 rocket launched from Cape Canaveral.

The Minotaur 4 usually comes with four stages, but the ORS-5 satellite’s equator-hugging orbit needed another boost. Instead of flying with a single Orion 38 rocket motor on top of the Peacekeeper missile stack, Saturday’s predawn launch carried two Orion 38 stages.

It was a case of necessity breeding invention, officials said.

The Minotaur 4 launched from Complex 46, a pad originally constructed for the U.S. Navy’s Trident missile program, then upgraded to support two Athena rocket launches in 1998 and 1999 for NASA and Taiwan. Space Florida, an arm of the state government, paid $6.6 million to refurbish the launch pad for the ORS-5 mission and future launch opportunities, according to Jim Kuzma, Space Florida’s chief operating officer.

Another launch from pad 46 using Peacekeeper rocket motors is scheduled in late 2019 for a suborbital in-flight abort test of NASA’s Orion crew capsule.

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