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Minotaur rocket readied for liftoff from Alaska next week

Posted: November 12, 2010

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Seven satellites will share a ride to space on a Minotaur rocket next Friday, launching from the southern shore of Alaska to an orbital perch more than 400 miles above Earth with a legion of U.S. military, NASA and university experiments.

Payloads of the STP-S26 mission are stacked for launch on a Minotaur 4 rocket. Credit: U.S. Air Force/Lou Hernandez
The Minotaur 4 rocket is scheduled for blastoff in a 90-minute launch window opening at 8:24 p.m. EST (4:24 p.m. Alaska time) next Friday, or 0124 GMT on Nov. 20.

The 78-foot-tall launcher, powered by surplus military and commercial rocket motors, is in the final stages of preparations at Launch Pad No. 1 at Kodiak Launch Complex in Alaska.

It will be the second orbital mission from the state-owned facility, which is managed by Alaska Aerospace Corp. and situated on the southeast coast of Kodiak Island.

"Over the past 18 months, our combined government and industry team has done an absolutely phenomenal job overcoming challenges from the logistics of transporting rocket motors to Kodiak Island, to the integration of seven payloads and their 16 experiments onto the rocket, to the numerous launch vehicle and range activities necessary to achieve a successful mission," said Air Force Col. Michael Moran, commander of the Air Force Space Development and Test Wing.

The launch customer is the U.S. Air Force Space Test Program, a unit devoted to demonstrating enabling technologies that could be incorporated on more costly and critical spacecraft in the future.

The mission is codenamed STP-S26, signifying the 26th small launch vehicle mission since the Space Test Program began flight testing in 1967.

"On this single rocket, we will launch seven satellites carrying 16 science and technology experiments from the Air Force, Army, Navy, NASA and the National Science Foundation," said Air Force Col. Carol Welsch, director of the Space Test Program.

The satellite cluster, totaling nearly 1,300 pounds, is already attached to the Minotaur's upper stage.

"Right now, we have the entire vehicle stacked with the encapsulated payload on the rocket," said Air Force Lt. Col. Tim Cole, the launch vehicle program manager. "We have done one rehearsal with the team. From here to the 19th, we will continue to check the systems, the avionics systems, the hydraulic systems, to make sure they are performing to what we expect."

Payloads of the STP-S26 mission are stacked for launch on a Minotaur 4 rocket. Credit: Alaska Aerospace Corp.
Another countdown rehearsal is planned Monday for a final exercise before launch day.

"Getting down to the last couple of days, we will test the flight termination system on the vehicle," Cole said. "We will test the range connection to the vehicle, so that we can get telemetry. We will do a system test. And then on the last day, we will remove the pins for the ordnance devices and be ready to launch."

The launch pad's clamshell-like service tower will be retracted next Friday.

The launch will be the third flight of the Minotaur 4, which is made of three solid rocket motors from stockpiles of retired Peacekeeper missile stages. A commercial Orion 38 fourth stage will inject the payloads into an orbit about 400 miles high with an inclination of 72 degrees.

After deploying the satellites, a liquid-fueled fifth stage will be tested for use on future Minotaur 4 flights. It carries ballast weights to be released in a higher orbit with an altitude of about 715 miles.

The Hydrazine Auxiliary Propulsion System, or HAPS, is designed for missions placing multiple satellites destined for different orbits. All of the operational payloads on this Minotaur mission are going to the same altitude, but future missions could require in-flight orbit changes.

The restartable HAPS thrusters have previously flown on air-launched Pegasus rockets, but not on the Minotaur.

"Although this is our third launch, we treat it like our first since we have several first items on-board, like the HAPS system," Cole said.