Military Microsatellites to Test Technologies in Wednesday Launch

This illustration details the MiTEX satellites and their Delta 2 booster. CREDIT: Boeing/DARPA via Spaceflight Now.

An experimental U.S. military project to test whether the advanced technologies embedded in two miniature satellites and a new upper stage kick motor can operate through the rigors of spaceflight will launch into orbit Wednesday evening from Cape Canaveral aboard a Boeing Delta 2 rocket.

The Micro-Satellite Technology Experiment, or MiTEx for short, is slated for liftoff at 5:34 p.m. EDT (2134 GMT). A four-hour launch window is available through 9:34 p.m. EDT (0134 GMT).

"MiTEx will investigate and demonstrate advanced space technologies such as lightweight power and propulsion systems, avionics and spacecraft structures; commercial-off-the-shelf processors; affordable, responsive fabrication/build-to-launch techniques; and single-string components," DARPA officials explained in mission information provided to Spaceflight Now.

The 12-story rocket will roar away from pad A of Complex 17 with its main engine and six strap-on boosters firing to create 789,000 pounds of thrust. A minute later, the three remaining solid-fuel boosters will light as the six ground-lit motors burn out and fall away.

Heading eastward across the Atlantic, the blue and white Delta will leave a smoky contrail from the solid boosters until the final three are extinguished just over two minutes into flight and separate more than 30 miles above the ocean.

That will leave the RS-27A first stage engine, consuming refined kerosene and supercold liquid oxygen, to push the rocket onward for another two minutes to an altitude of 70 miles (112 kilometers) before shutting down. The spent stage then jettisons, allowing the hypergolic-fueled second stage to ignite.

Moments later, the two-piece nose cone that shrouded the payload during ascent through the atmosphere is commanded to spring open and separate.

The second stage engine will deliver the rocket into an initial orbit with a high point of 154 statute miles (247 kilometers) and low point of 103 miles (165 kilometers) when it shuts down at T+plus 10 minutes, 22 seconds after liftoff.

The vehicle will coast in that orbit for 12 minutes before the engine is re-started for a 73-second burn to reach an intermediate orbit with a high point of 1,380 statute miles (2,220 kilometers) and low point of 105 miles (168 kilometers). Tiny thrusters on the side of the rocket then spin up the third stage in preparation for separation. The two stages split at T+plus 23 minutes, 31 seconds, followed 37 seconds later by ignition of the solid-fuel third stage for its 86-second burn.

The third stage targets a highly elliptical geosynchronous transfer orbit with a high point of 22,490 statute miles (36 194 kilometers), low point of 115 miles (185 kilometers) and inclination of 25.24 degrees to the equator.

At T+plus 30 minutes and 24 seconds while cruising 375 miles (603 kilometers) above south-central Africa, the third stage releases from the MiTEx upper stage with its still-attached satellites. That will complete the Delta 2 rocket's role in the MiTEx mission.

The Defense Advanced Research Projects Agency (DARPA) is spearheading the MiTEx effort to evaluate the usefulness of small satellite technologies and the prototype upper stage to support future military programs.

But before the two satellites can begin their year-long missions, the stage has to place the craft into the intended orbit.

Developed by the U.S. Naval Research Laboratory, the experimental motor will put several new technologies to the test including:

• Platinum/rhodium bi-propellant attitude control thrusters
• High-performance coated columbium delta-V thruster
• Commercial off-the-shelf manual valve tested to aerospace standards
• Light-weight Inconel-718 composite overwrap pressure vessels
• Lightweight titanium propellant tanks with internal propellant management devices
• Triple junction solar cells
• Lithium-ion batteries
• A low-cost/high-performance star tracker

The stage will ferry the two MiTEx satellites from the egg-shaped geosynchronous transfer orbit reached by the Delta 2 rocket to the circular geostationary orbit 22,300 miles (35,888 kilometers) above the equator. That high orbit allows spacecraft to match the planet's rotation and appear fixed over one location.

Once arriving in geostationary orbit, the satellite pair will be deployed from the stage to begin independent lives examining the value of operating miniature craft from such a high vantage point above Earth. The demonstration will give military planners real-life experience to draw upon when designing new projects.

The MiTEx spacecraft weigh about 500 pounds (226 kilograms) each. Orbital Sciences built one satellite and Lockheed Martin the other.

"The satellites will conduct a variety of experiments in autonomous operations and maneuvering and station-keeping. MiTEx will also demonstrate the ability to launch multiple small satellites into GEO orbit," according to DARPA officials.

Geostationary orbit is the home to government and commercial communications satellites, plus spy spacecraft for eavesdropping reconnaissance missions and missile-launch detection.

The price tag for MiTEx has not been released. And the exact parking spots in geostationary orbit for the two spacecraft aren't being revealed.

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