Spaceflight Insider

Orbital ATK launches ORS-5 space surveillance satellite atop Minotaur IV

Orbital ATK's Minotaur IV rocket zips toward space with the ORS-5 satellite. Photo Credit: Michael Deep / SpaceFlight Insider

Orbital ATK’s Minotaur IV rocket zips toward space with the ORS-5 satellite. Photo Credit: Michael Deep / SpaceFlight Insider

CAPE CANAVERAL, Fla. — The Operationally Responsive Space 5 (ORS-5) spacecraft, alternately known as SensorSat, lifted off on an Orbital ATK Minotaur IV rocket at 2:04 a.m. EDT (06:04 GMT) Aug. 26, 2017, from long-dormant Space Launch Complex 46 at Cape Canaveral Air Force Station on the Florida coast. The satellite was placed into a low-Earth orbit (LEO).

Liftoff took place near the end of a nearly four-hour long launch window. The reason for the postponement was the weather.

Several hours from the 11:15 p.m. EDT Aug. 25 (03:15 GMT Aug. 26) opening of the window, a hold was called because of lightning in the area, postponing the flight by more than an hour. Moreover, the window itself was reduced by 15 minutes to close at 3 a.m. EDT (07:00 GMT) Aug. 26.

Launch profile for the launch of Orbital ATK's Minotaur IV rocket with the U.S. Air Force's ORS-5 mission. Image Credit: Orbital ATK

Launch profile for the launch of Orbital ATK’s Minotaur IV rocket with the U.S. Air Force’s ORS-5 mission. Image Credit: Orbital ATK

By 11:30 p.m. EDT (03:30 GMT) a new T-zero was set for 2:04 a.m. EDT (06:04 GMT). Additionally, forecasters from the 45th Weather Squadron predicted better odds of acceptable weather: 30 percent.

Throughout the rest of the countdown, no major issues cropped up and the vehicle launched into the blackness of space on a nearly 30-minute trip to place ORS-5 into its designated orbit.

“The ORS-5 Minotaur IV launch was the true epitome of partnership,” said Brig. Gen. Wayne Monteith in a press release by the 45th Space Wing. “A collaborative effort between multiple mission partners, each group came together flawlessly to revolutionize how we work together on the Eastern Range. Teamwork is pivotal to making us the ‘World’s Premier Gateway to Space’ and I couldn’t be prouder to lead a Wing that not only has launched over a quarter of the world’s launches this year, but also three successful, launches from three different providers, in less than two weeks.”

Reawakening a disused pad

SLC-46 (commonly referred to as Pad 46) played host to the launch of the repurposed Intercontinental Ballistic Missile (ICBM).

“Launching from Cape Canaveral Air Force Station expands the Minotaur launch vehicle’s capability to meet specific mission requirements for our customer,” said Rich Straka, Vice President and General Manager of Orbital ATK’s Launch Vehicles Division via a release issued by the company. “We are pleased to be able to provide continued launch support for the ORS office with our reliable Minotaur family of launch vehicles and look forward to a successful launch of the ORS-5 mission.”

Pad 46 has a history of serving as a launch site for ballistic missile tests. The last of these was the flight of a Trident II missile that took place in 1989. After sitting idle for eight years, Space Florida began using the launch site for commercial launches of the Athena rocket.

Although SLC-46 has played host to several launches in the following years, it again fell silent after its last mission. A Lockheed Martin Athena I launched FORMOSAT-1 (formerly known as ROCSAT-1), Taiwan’s first satellite, in 1999.

Now revived, Pad 46 also looks ahead to missions by Vector Space Systems and as well as NASA for its Orion Ascent Abort 2 (AA-2) test flight, currently scheduled to take place in 2018.

Photo Credit: Tom Cross / SpaceFlight Insider

Photo Credit: Tom Cross / SpaceFlight Insider

From swords to plowshares

The Minotaur IV rocket used for the ORS-5 mission is composed of four stages, three of which are leftover motors from the LGM-118 Peacekeeper ICBM program. The Minotaur is viewed as a cost-effective and efficient re-use of hardware for peacetime purposes.

While Orbital ATK is reusing motors that were leftover from the ICBM program, the Dulles, Virginia-based company wants permission to make use of the now-unused vehicles that were decommissioned as part of the START II arms reduction program.

Though the United States Air Force is supportive of repurposing the decommissioned missiles for commercial launches, other commercial providers are less enthusiastic (as this would mean more competition). Orbital ATK, however, is striving to use these former tools of war for peaceful purposes.

“Currently, the Air Force maintains around a thousand excess ICBMs, which are stored in bunkers at two military bases in the United States,” Mark Pieczynski, Orbital ATK’s Vice President of Business Development, Flight Systems Group, told SpaceFlight Insider in 2016. “We and other companies would like to purchase those at a fair market price and bolster the U.S. market.”

In the meantime, the company will utilize its stockpile of spare motors to produce more Minotaur IV launch vehicles. Tonight’s launch was the sixth Minotaur IV flight.

The first three of the vehicle’s four stages are composed of the repurposed missile’s solid-fueled motors. The first stage is the SR-118 motor, which is capable of producing 490,000 pounds-force (2,200 kilonewtons) of thrust, followed by the SR-119 with 307,000 pounds-force (1,365 kilonewtons) on the second stage, and the third stage’s SR-120 with 74,000 pounds-force (329 kilonewtons) – rounding out the trio.

The vehicle’s fourth stage is the commercially available Orion 38 solid-fueled motor, which is capable of generating some 7,200 pounds-force (32.2 kilonewtons) of thrust. It has been used on previous Minotaur launches as well as on Orbital ATK’s Pegasus air-launched rocket.

The Minotaur family of launch vehicles began their operational career in January 2000 with the flight of JAWSAT-1 atop a Minotaur 1 booster. Since that time, 25 successful missions have taken place using the reliable launch vehicle.

“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 via a release issued by the company. “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 ORS 5 spacecraft during buildout and testing at MIT. Photo credit: Lincoln Lab / MIT

Eyes to the sky

While many surveillance satellites have their sensors trained at terrestrial targets, upon reaching orbit, SensorSat will turn its hardware skyward. Though the spacecraft will operate in LEO, in a 372.8-mile (600-kilometer) circular orbit, it will scan the valuable space located at the much higher geosynchronous equatorial orbit (GEO) altitude.

The satellite was built for the USAF by Lincoln Laboratory at the Massachusetts Institute of Technology (MIT) and is being launched to monitor the space more than 22,236 miles (35,786 kilometers) above the equator. With the GEO space representing a significant operational area for military satellite operations, the USAF hopes the mission will provide enhanced monitoring and detection of threats and targets of interest.

Although small in size, SensorSat packs a substantial amount of capability into its 309-pound (140-kilogram) framework.

The primary instrument is the spacecraft’s imaging package. Normally requiring a significantly larger sensor to gather the required detail, SensorSat is able to reduce the size of the detector to one-tenth the area by utilizing an off-zenith imaging angle. Dubbed the “magic angle”, this oblique imaging alignment permits the image of the target to remain stationary on SensorSat’s camera sensor, allowing for greater fidelity than might otherwise be possible.

Indeed, the sensitivity of the classified instrument is able to scan and track both satellites in GEO, as well as debris that might threaten the space.

SensorSat is designed to be a gap filler mission for the Space-Based Space Surveillance System (SBSS) Block 10 mission that was launched in 2010, though it cost less than 10 percent of its older sibling.

In the end, the ORS-5 mission is, primarily, a technology demonstrator, one lofted to help validate concepts and technologies for future missions.

Video courtesy of InterSpace



Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.

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