Spaceflight Insider

Pathfinder for Minotaur IV rocket stacked at SLC-46

Minotaur IV Pathfinder at Cape Canaveral's Space Launch Complex 46 in Florida. Orbital ATK recently conducted a pathfinder test of the SLC-46 launch tower. Photo Credit: Jason Rhian / SpaceFlight Insider

Minotaur IV Pathfinder at Cape Canaveral’s Space Launch Complex 46 in Florida. Orbital ATK recently conducted a pathfinder test of the SLC-46 launch tower at the historic site. Photo Credit: Jason Rhian / SpaceFlight Insider

CAPE CANAVERAL, Fla. — In an effort to ready Space Launch Complex (SLC) 46 for launching an Orbital ATK Minotaur IV rocket later this year, three inert pathfinder motors were stacked at the historic launch site. Space Florida invited the media to see the completed stack on Sunday, Feb. 12, 2017.

The purpose of the pathfinder was to test the new infrastructure at SLC-46. The U.S. Air Force’s Operationally Responsive Space 5 (ORS-5) satellite is scheduled to take to the skies from the site later this summer. If everything goes as planned, it will mark the first Minotaur IV rocket to fly out of Florida. Liftoff is tentatively scheduled for 1:00 a.m. EDT (05:00 GMT) on July 15.

Space Florida's Mark Bontrager (left) and Orbital ATK's Terry Luchi share insights into the upcoming ORS-5 mission and future commercial space efforts along Florida's Space Coast. Photo Credit: Michael Howard / SpaceFlight Insider

Space Florida’s Mark Bontrager (left) and Orbital ATK’s Terry Luchi share insights into the upcoming ORS-5 mission and future commercial space efforts along Florida’s Space Coast. Photo Credit: Michael Howard / SpaceFlight Insider

“This operation today is meant to verify all of the interfaces and modifications [function properly] that have taken place out here at LC-46 in support of the Minotaur IV launch vehicle,” Terry Luchi, Director of Minotaur Programs, Orbital ATK Launch Vehicles Division told SpaceFlight Insider. “This summer’s launch will mark the first time that we’ve launched a Minotaur IV from this particular launch site, so all of these tests will provide extremely valuable data in support of this flight.”

The payload for this mission is SensorSat, a 176- to 243-pound (80- to 110-kilogram) satellite designed to test technologies for future space situational-awareness satellites in geostationary orbit.

While most of the ORS-5 mission is classified, SensorSat is designed to orbit at approximately 370 miles (600 kilometers) above the Earth over the equator. It was that orbital requirement that necessitated launching from the Cape instead of out of Wallops Island, Virginia, where another Minotaur pad is located.

The special five-stage Minotaur IV will actually change planes from the 28 degrees it will initially achieve out of the Cape to zero degrees over the equator. The vehicle doesn’t have enough energy to complete that task if launched from the higher latitude Wallops site.

This summer’s launch will be the first flight from SLC-46 in more than 18 years (the last mission to be launched from SLC-46 was Taiwan’s first satellite, ROCSAT-I, which flew to orbit atop an Athena 1 booster).

The pad, constructed in the 1980s, saw test flights of the Trident II missile between 1987 and 1989. The site was then deactivated until 1997 when Space Florida, an aerospace development agency of Florida, leased the pad to Lockheed Martin. In turn, the Bethesda, Maryland-based company used SLC-46 from which to launch an Athena II from the complex in 1998 and an Athena I in 1999. The complex has sat idle since that time – until now.

According to Orbital ATK, the 45th Space Wing issued Real Property Licenses to Space Florida in 2010 for SLC-36 and 46. The Federal Aviation Administration issued a Launch Site Operator’s License for commercial launches at SLC-46 that same year. The ORS-5 mission will the first flight under this new structure.

Orbital ATK‘s Minotaur IV is derived from the three-stage LGM-118 Peacekeeper ICBM. Each of those three stages uses a solid propellant. At liftoff, the first stage produces an estimated 490,000 lbf (2,180 kN) of thrust.

It’s first flight took place on April 22, 2010, from Vandenberg Air Force Base located in California. Additionally, versions of the rocket have launched from the Kodiak Launch Complex in Alaska.

The final two stages of the 78-foot (24-meter) tall five-stage Minotaur IV rocket that will be used for the ORS-5 mission will be commercially-derived. If everything goes as planned, they will finish placing SenorSat into orbit and change the plane of the spacecraft once over the equator. The whole flight will last about 30 minutes.

Twenty-five Minotaur family rockets have launched since 2000. In the decade since that time, some five of the rockets have been sent aloft. All of them have launched successfully.

Technicians started de-stacking the pathfinder rocket on Monday. The Minotaur IV that will be used for this summer’s mission will be stacked three weeks prior to the planned T–0. It will then undergo about a week and a half of preflight testing.

This weekend’s tests were just another step toward revitalizing the launch sites located at Cape Canaveral and they served to highlight that once-dormant locations are being refurbished to service new launch systems.

“This is the first time that this launch complex has seen flight hardware since 1999,” Mark Bontrager, the Vice President of Spaceport Operations for Space Florida told SpaceFlight Insider. “Since that time, this pad has not been used and Space Florida has been working hard for the past three or four years to bring the infrastructure up to speed, including communications with the range and the above ground infrastructure to enable launches to once again take place from Launch Complex 46.”

Plaque highlighting the history of Trident II launches at Launch Complex 46. Photo Credit: Carleton Bailie / SpaceFlight Insider

Plaque highlighting the history of Trident II launches at Launch Complex 46. Photo Credit: Carleton Bailie / SpaceFlight Insider



Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a blog about the International Space Station, called Orbital Velocity. He met with members of the SpaceFlight Insider team during the flight of a United Launch Alliance Atlas V 551 rocket with the MUOS-4 satellite. Richardson joined our team shortly thereafter. His passion for space ignited when he watched Space Shuttle Discovery launch into space Oct. 29, 1998. Today, this fervor has accelerated toward orbit and shows no signs of slowing down. After dabbling in math and engineering courses in college, he soon realized his true calling was communicating to others about space. Since joining SpaceFlight Insider in 2015, Richardson has worked to increase the quality of our content, eventually becoming our managing editor. @TheSpaceWriter

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