A Proton rocket is ready to bolster DirecTV's high-definition broadcasting service to the United States with Monday night's launch of a new communications satellite from Kazakhstan.

Artist's concept of DirecTV 12. Credit: Boeing

The 191-foot-tall rocket is set to launch at 0022 GMT Tuesday (7:22 p.m. EST Monday) from pad 39 at the Baikonur Cosmodrome in Kazakhstan. It will take 9 hours for the Proton and Breeze M upper stage to put DirecTV 12 in the planned high-altitude orbit.

The satellite will complete DirecTV's phased expansion of high-definition television service to U.S. households. DirecTV 12 was built by the satellite-manufacturing division of Boeing Co. in El Segundo, Calif.

"The successful launch and deployment of DirecTV 12 will bring the best in digital television programming to DirecTV's 18.4 million customers across the United States," said Craig Cooning, vice president and general manager of Boeing Space and Intelligence Systems.

DirecTV 12 will allow the direct-to-home broadcasting firm to expand its HD capacity by 50 percent, according to Boeing.

From its station in geosynchronous orbit along the equator at 102.8 degrees west longitude, DirecTV 12 will reach subscribers in the continental United States, Alaska and Hawaii. The satellite is designed to operate for 15 years.

DirecTV 12 will join two identical spacecraft launched in 2007 and 2008. The trio of satellites were ordered to bolster DirecTV's HDTV offering and continue the company's legacy of uninterrupted service.

After DirecTV 12 enters service next year, the company will provide 200 national HD channels and 1,500 local HD channels to customers.

The spacecraft carries 131 Ka-band transponders for nationwide service and local programming. The communications payload uses two 9.2-foot reflectors and nine smaller antennas.

DirecTV 12 weighs about 13,000 pounds at launch, filling nearly all of the Proton rocket's lift capacity. International Launch Services, the launcher's commercial marketing firm, and Russian rocket-builder Khrunichev have implemented several recent upgrades to the Proton to give the booster the power to launch such large satellites, according to Frank McKenna, president of ILS.

Workers rolled the Proton rocket on rail tracks from a fueling station to the launch complex early Friday. The silver and white launch vehicle was lifted vertically atop the pad shortly after sunrise.

The Proton rocket is lifted atop the launch pad on Friday morning. Credit: Roscosmos

The booster's six RD-276 first stage engines will ignite at T-minus 1.75 seconds, building up to more than 2 million pounds of thrust at the point of liftoff.

After liftoff, the Proton will pass the speed of sound in the first minute of flight, soaring into the upper atmosphere and jettisoning its first stage 2 minutes into the launch.

The rocket's second stage will fire for more than 3 minutes, giving way to the Proton's third stage at T+plus 5 minutes, 26 seconds. The vehicle's payload fairing, which protects DirecTV 12 during the early phase of launch, will be released at T+plus 5 minutes, 48 seconds, according to ILS.

The Proton's third stage will separate from the Breeze M upper stage at T+plus 9 minutes, 36 seconds. At that point, the Breeze M and DirecTV 12 should be on a suborbital trajectory.

The hydrazine-fueled upper stage will ignite for the first of five burns at T+plus 11 minutes, 50 seconds for a 4-minute firing to place DirecTV 12 in a temporary parking orbit with an inclination of 48 degrees.

Four more burns of the Breeze M will guide DirecTV 12 into a target orbit with a high point of 22,236 miles, a low point of 3,181 miles and an inclination of 20.7 degrees, according to ILS.

Spacecraft separation is planned at 0932 GMT (4:32 a.m. EST) Tuesday.