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The Mission

Rocket: Taurus XL
Payload: OCO
Date: Feb. 24, 2009
Time: 1:51 a.m. PST (4:51 a.m. EST)
Site: SLC-576E, Vandenberg Air Force Base, California

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Follow the countdown and launch of the Taurus XL rocket with the Orbiting Carbon Observatory spacecraft. Reload for the latest updates.

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NASA's first environmental satellite dedicated to mapping atmospheric carbon dioxide has been cleared for launch early Tuesday aboard from California aboard an Orbital Sciences Taurus XL rocket.

The final launch readiness review was held Sunday afternoon and affirmed all systems were "go" for the Orbiting Carbon Observatory mission.

The Combined Systems Test between the Taurus rocket and its payload was successfully completed Friday and the access scaffolding around the pad was taken down Saturday.

Launch countdown activities will get underway Monday evening.

Tuesday's middle-of-the-night liftoff is targeted for 1:51 a.m. local time (4:51 a.m. EST).

Air Force meteorologists report there's an 80 percent chance of acceptable weather for the launch.

The OCO spacecraft will fly 438 miles above the planet in polar orbit, collecting about 8 million measurements every 16 days to create maps showing global distribution of carbon dioxide.

"It's critical that we understand the processes controlling carbon dioxide in our atmosphere today so we can predict how fast it will build up in the future and how quickly we'll have to adapt to climate change caused by carbon dioxide buildup," said David Crisp, the OCO principal investigator at NASA's Jet Propulsion Laboratory.

Scientists say carbon dioxide is the leading human-produced greenhouse gas driving changes in Earth's climate.


Final assembly of the Taurus XL rocket was underway Wednesday at Vandenberg Air Force Base, piecing together the multi-stage booster and its environmental payload at a minimalist launch pad on the central coast of California.

Liftoff is scheduled for 1:51 a.m. PST (4:51 a.m. EST; 0951 GMT) next Tuesday to deliver NASA's Orbiting Carbon Observatory into polar orbit.

Known for its simplistic launch site devoid of any large gantry or major infrastructure, the Taurus rocket is a four-stage, all solid-fuel booster designed to carry small satellites into space.

Operated by Orbital Sciences, the Taurus is a ground-based rocket derived from the company's air-launched Pegasus vehicle. In fact, the Taurus and Pegasus use three common stages. But what makes Taurus different is the addition of a bottom stage to power the initial climb away from Earth.

Taurus debuted in 1994 and has six successful flights to its credit, putting 10 satellites into orbit.

Next week's mission will carry OCO, NASA's first spacecraft dedicated to mapping atmospheric carbon dioxide and the human impact to climate change.

Stacking of the Taurus rocket began January 29 when the first stage was mounted atop the pad's pedestal, a 24-foot tall stand affectionally dubbed the milk stool.

The first stage is a Castor 120 motor manufactured by Alliant Techsystems, the maker of all four Taurus stages.

The upper three motors are the Orion 50SXLG second stage, the Orion 50XL third stage and the Orion 38 fourth stage. They were integrated in Orbital's Building 1555 hangar at Vandenberg, then hauled to the Taurus pad via a special trailer on February 3.

Once at the pad, the site of an abandoned missile silo and now known as Space Launch Complex 576E, the three combined upper stages were housed inside a large portable tent where the final assembly work between the rocket and satellite could be performed in a safe horizontal position.

OCO underwent testing in a processing facility on base, then got enclosed within the two-piece shroud that serves as the rocket's 63-inch-diameter nose cone during launch. Technicians trucked the encapsulated satellite to the pad a week ago, rotating it horizontal at the tent's doorway to join the waiting rocket stages.

The payload was attached to the fourth stage on Monday.

The tent was moved out of the way early Wednesday morning, giving large cranes brought into the pad full access to the combined stages and OCO.

Two cranes working in tandem hoisted the upper stack off the horizontal transporter and turned the slender space hardware into a vertical position. Within minutes, the rocket was maneuvered atop the first stage waiting on the pad.

Crews quickly went to work bolting the upper portion of the vehicle to the first stage under brilliant blue skies. Later, technicians standing in the basket of a cherry-picker released the lifting fixtures that held the rocket during the move.

A gallery of photos showing the rocket's pre-launch processing campaign can be seen here.

There is no mobile service structure or towering gantry at the Taurus pad. Simple scaffolding temporarily erected around the first stage and the cranes give workers the access they require during the rocket's brief stay on the pad.

Now standing fully assembled, the Taurus is 93 feet tall and 81 tons in weight.

Final testing and readiness reviews are planned over the next few days leading into Monday night's countdown.

Watch this page for live updates during the count and the ascent into orbit!

Copyright 2009, all rights reserved.

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