Lighting up the overnight sky with a brilliant streak of fire, an Orbital ATK Minotaur 4 rocket, powered by a mix of new motors and decades-old stages from decommissioned ICBMs, blasted a small Air Force satellite into orbit early Saturday to keep tabs on critical high-altitude military and civilian satellites — and any threats they might face.
Made up of five solid-fuel stages — including three salvaged from decommissioned Peacekeeper missiles, the eight-story-tall Minotaur 4 roared to life with a burst of fiery exhaust at 2:04 a.m. EDT (GMT-4), briefly turning night into day as it leaped away from pad 46 at the Cape Canaveral Air Force Station.
The first three Peacekeeper stages fired in succession over the next three-and-a-half minutes, putting on a spectacular show as they propelled the rocket out of the lower atmosphere to an altitude of about 120 miles some 328 miles east of the launch site.
After a 10-minute coast, the fourth stage ignited for a one-minute burn, putting the vehicle in a predicted 249-by-372 mile orbit tilted 24.5 degrees to the equator. The rocket’s fifth stage fired 10 minutes later to circularize the orbit at 372 miles and to eliminate the tilt, putting the spacecraft on a trajectory directly above the equator.
Twenty-eight minutes after launch, the $49 million ORS-5 satellite, also known as “SensorSat,” was released to fly on its own.
Orbital ATK has launched Minotaur rockets in various configurations from California, Alaska and Virginia, but Saturday’s flight was the first from Cape Canaveral where the state of Florida makes pad 46 available on a commercial basis for relatively small rockets.
The ORS-5/SensorSat satellite, built by the Massachusetts Institute of Technology’s Lincoln Laboratory, is equipped with a single instrument, a telescope designed to monitor satellites in geosynchronous orbit 22,300 miles above the equator.
At that altitude, spacecraft take 24 hours to complete one orbit and thus appear stationary in the sky, making the “geo belt” especially valuable real estate for communications satellites, weather stations, Earth observation spacecraft and a variety of military vehicles.
Managed by the Air Force Operationally Responsive Space office, SensorSat will operate in a much lower orbit, repeatedly scanning the geo belt above to help analysts keep track of current spacecraft and any potential threats, either from adversaries or due to space debris.
The satellite measures just three feet long by about 1.5 feet wide. “It would fit conveniently on somebody’s coffee table,” said Grant Stokes, a senior manager at MIT’s Lincoln Laboratory.
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SOURCE: CBS News, William Harwood
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