BY JUSTIN RAY

Additional coverage for subscribers:
VIDEO: TAURUS LAUNCH OF OCO SATELLITE FAILS PLAY
VIDEO: FAILURE DECLARED BY NASA LAUNCH DIRECTOR PLAY
VIDEO: POST-FAILURE NEWS BRIEFING PLAY

VIDEO: HIGHLIGHTS OF THE TAURUS LAUNCH CAMPAIGN PLAY
VIDEO: HIGHLIGHTS OF THE SATELLITE LAUNCH CAMPAIGN PLAY
VIDEO: PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: MISSION SCIENCE PREVIEW BRIEFING PLAY
VIDEO: ORBITING CARBON OBSERVATORY OVERVIEW PLAY
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FRIDAY, JULY 17, 2009

Investigators could not find a definitive cause of the February launch failure that doomed a $273 million environmental satellite, but officials recommended a series of improvements for the Taurus rocket in a report released Friday.

Read our updated story.

FRIDAY, MARCH 20, 2009

Climate scientists are making the case to NASA for a new satellite to replace a $273 million carbon dioxide monitoring mission lost in a launch failure last month.

Read our updated story.

TUESDAY, FEBRUARY 24, 2009
1440 GMT (9:40 a.m. EST; 6:40 a.m. PST)

NASA's $273 million Orbiting Carbon Observatory satellite crashed into the ocean near Antarctica shortly after launch today from Vandenberg Air Force Base, Calif., atop an Orbital Sciences Corp. Taurus XL booster. Telemetry indicated a protective nose cone fairing failed to separate early in the climb to space, weighing the rocket down and preventing the spacecraft from reaching orbit.

Read our updated story.

1343 GMT (8:43 a.m. EST; 5:43 a.m. PST)

John Brunschwyler, Taurus program manager from Orbital Sciences, explains what was supposed to happen during the nose cone separation and what actually occurred this morning:

"The fairing separates by a sequence of electrical pulses that drive ordnance. The clamshell fairing is a two-piece device and it's separated first with four pulses from an electronics box. These are two primary pulses and two redundant pulses, which separate along the fairing rails, which is the vertical part, if you will, of the fairing. About 80 milliseconds later, the base joint is severed in a similar fashion, that is with four pulses - two primary and two redundant.

"We have confirmation that the correct sequence was sent by the software. We had good power going into this event, and we also had healthy indications of our electronics box that sent the signal. Once that time had passed, which was about three minutes into the flight, we observed various pieces of telemetry that, of course, we then tried to correlate. Because at first, being humans, we don't necessarily believe one piece of data and we need to correlate the various pieces to kind of come to a conclusion. And indeed we did come to a conclusion later in the flight."

The pieces of the telemetry puzzle that showed the fairing had failed to separate included the breakwire signals not indicating a jettison, the fairing temperature sensors continuing to function later during ascent and engineers not seeing the jump in acceleration that was expected after fairing would have been shed.

"As a direct result of carrying that extra weight, we could not make orbit," Brunschwyler said.

1335 GMT (8:35 a.m. EST; 5:35 a.m. PST)

"Let me say that our whole team, at a very personal level, are disappointed in the events of this morning. It's very hard and like I said, we are, at a very personal level, upset with the results," said John Brunschwyler, Taurus program manager from Orbital Sciences.

1330 GMT (8:30 a.m. EST; 5:30 a.m. PST)

A statement from Taurus operator Orbital Sciences:

"Orbital will immediately convene an internal failure investigation board that will include representatives from the company and NASA to determine the cause of todayıs launch failure. Orbital believes that it is likely that it gathered sufficient data during the flight that will enable the company to identify the cause of the failure."

1315 GMT (8:15 a.m. EST; 5:15 a.m. PST)

The Orbiting Carbon Observatory has failed to reach orbit around Earth because the nose cone of the Taurus rocket failed to separate.

The weight of the shroud meant the rocket couldn't reach orbital speed and fell back into the ocean, landing near Antarctica, according to John Brunschwyler, Taurus program manager from Orbital Sciences.

It is not known what prevented the fairing from jettisoning about three minutes into the flight.

"We had indications that the sequence was sent, but shortly after that we started getting indications that the fairing did not separate," NASA launch director Chuck Dovale said.

Separation of the shroud had been announced in real-time by the launch team. Obviously, that was in error.

1258 GMT (7:58 a.m. EST; 4:58 a.m. PST)

A gallery of launch photos from this morning's liftoff of the Taurus rocket is posted here.

1210 GMT (7:10 a.m. EST; 4:10 a.m. PST)

This morning's post-failure press conference has been rescheduled for 5 a.m. PST (8 a.m. EST; 1300 GMT).

1105 GMT (6:05 a.m. EST; 3:05 a.m. PST)

The Taurus rocket's 63-inch diameter payload fairing is built by the Vermont Composites division for Orbital Sciences. The fairing's two halves are made of graphite-epoxy composite materials with an aluminum honeycomb core. This particular shroud has performed well in its five previous Taurus missions before today's mishap.

According to the Taurus Users Guide, the two halves of the fairing are structurally joined along their longitudinal interface using a frangible joint system. An additional circumferential frangible joint at the base of the fairing attaches the fairing to the upper stage assembly.

"At separation, a gas pressurization system is activated to pressurize the fairing deployment thrusters. The fairing halves then rotate about external hinges that control the fairing deployment to ensure that payload and launch vehicle clearances are maintained. All elements of the deployment system have been demonstrated through test to comply with stringent contamination requirements."

A pre-launch photo showing the Orbiting Carbon Observatory spacecraft and the nose cone can be seen here.

1050 GMT (5:50 a.m. EST; 2:50 a.m. PST)

NASA's $273 million Orbiting Carbon Observatory mission failed today during launch from Vandenberg Air Force Base, Calif., when the protective nose cone fairing failed to separate properly in the climb to space, agency officials said.

Read our full story here.

1036 GMT (5:36 a.m. EST; 2:36 a.m. PST)

"Right now, we do know that we have not had a successful launch tonight and will not be able to have a successful OCO mission," NASA launch commentator George Diller says.

1035 GMT (5:35 a.m. EST; 2:35 a.m. PST)

From NASA launch commentator George Diller:

"The OCO spacecraft did not achieve orbit successfully in a way that we could have a mission. They're still looking at the telemetry data very carefully.

"It appears we were getting indications the fairing was having problems separating. It either did not separate or did not separate in the way that it should. At any rate, we're still trying to evaluate exactly what the status of the spacecraft is at this point, and confirm the location and the orbit and exact state that the spacecraft is in. However, the data surrounding fairing separation does not appear to be what we expected to see. So that's what we believe has probably happened."

1020 GMT (5:20 a.m. EST; 2:20 a.m. PST)

"The nature of the failure is the fairing did not separate from around the spacecraft," NASA spokesman George Diller said, adding that a press conference would be held approximately two hours from now.

1016 GMT (5:16 a.m. EST; 2:16 a.m. PST)

The word from NASA launch commentator George Diller:

"This is Taurus launch control. It appears that we have had a launch contingency. We don't have the exact nature of the loss of mission, but NASA launch director Chuck Dovale has directed that the launch contingency plan be implemented. We will try to bring you any additional information as soon as we have it."

1015 GMT (5:15 a.m. EST; 2:15 a.m. PST)

Here's the announcement from NASA launch director Chuck Dovale when the failure was declared:

"It appears we've had a contingency with the OCO mission. Please enact the mission mishap preparedness and contingency plan. Begin with notification, data impoundment and mishap response tasks. Do not leave your stations until released by the NLM or the ALM. Do not attempt to call out and release information to anyone or speculate on the cause of the contingency. I'll come back on this net and instruct you further."

1013 GMT (5:13 a.m. EST; 2:13 a.m. PST)

NASA says the rocket's nose cone did not jettison as planned, causing today's launch to end in failure.

Separation of the shroud had been announced by the launch team. However, it appears that was in error.

1009 GMT (5:09 a.m. EST; 2:09 a.m. PST)

FAILURE. Today's launch has failed. NASA launch manager Chuck Dovale has ordered mishap procedures to begin. It is not known at this time what has occurred.

1008 GMT (5:08 a.m. EST; 2:08 a.m. PST)

T+plus 12 minutes, 30 seconds. The Taurus rocket's upper stage finished its firing, Orbital says.

1007 GMT (5:07 a.m. EST; 2:07 a.m. PST)

T+plus 11 minutes, 45 seconds. The rocket's attitude remains normal.

1006 GMT (5:06 a.m. EST; 2:06 a.m. PST)

T+plus 11 minutes, 15 seconds. Fourth stage ignition is confirmed.

1004 GMT (5:04 a.m. EST; 2:04 a.m. PST)

T+plus 9 minutes. The rocket is positioning itself to the fourth stage ignition orientation as planned.

1003 GMT (5:03 a.m. EST; 2:03 a.m. PST)

T+plus 7 minutes, 30 seconds. All systems still reported in good shape as the rocket continues to coast.

1002 GMT (5:02 a.m. EST; 2:02 a.m. PST)

T+plus 6 minutes, 45 seconds. Taurus is 300 miles above the Pacific now.

1001 GMT (5:01 a.m. EST; 2:01 a.m. PST)

T+plus 6 minutes. Orbital reports that all systems are operating normally. Ignition of the fourth stage is expected at about T+plus 11 minutes, 9 seconds.

1000 GMT (5:00 a.m. EST; 2:00 a.m. PST)

T+plus 4 minutes, 45 seconds. The downrange P-3 tracking aircraft positioned over the Pacific has acquired the rocket's signal for data relay back to Vandenberg.

1000 GMT (5:00 a.m. EST; 2:00 a.m. PST)

T+plus 4 minutes, 30 seconds. The third stage has finished firing. The Taurus rocket now enters a brief ballistic coast to reach the high point of its current trajectory before the fourth stage ignites to circularize the orbit.

0959 GMT (4:59 a.m. EST; 1:59 a.m. PST)

T+plus 4 minutes, 15 seconds. The vehicle's attitude is stable during the third stage burn. Altitude now 175 miles, speed 14,000 mph.

0959 GMT (4:59 a.m. EST; 1:59 a.m. PST)

T+plus 3 minutes, 40 seconds. Taurus is 130 miles up and traveling at 11,000 mph.

0958 GMT (4:58 a.m. EST; 1:58 a.m. PST)

T+plus 3 minutes, 14 seconds. With the Taurus' nose cone enclosing the Orbiting Carbon Observatory during atmospheric ascent no longer needed, the fairing has been jettisoned.

0958 GMT (4:58 a.m. EST; 1:58 a.m. PST)

T+plus 3 minutes. Burnout and separation of the rocket's second stage just occurred. And now the Orion 50XL third stage has been lit.

0957 GMT (4:57 a.m. EST; 1:57 a.m. PST)

T+plus 2 minutes. The rocket is stable as the Orion 50SXLG second stage continues to burn.

0957 GMT (4:57 a.m. EST; 1:57 a.m. PST)

T+plus 1 minute, 40 seconds. Taurus is traveling at 5,000 mph at an altitude of 50 miles.

0957 GMT (4:57 a.m. EST; 1:57 a.m. PST)

T+plus 1 minute, 30 seconds. The initial staging event of the launch has occurred. The rocket's second stage ignited and the spent first stage was jettisoned to fall into the Pacific Ocean.

0956 GMT (4:56 a.m. EST; 1:56 a.m. PST)

T+plus 45 seconds. Passing through the region of maximum aerodynamic pressure in the dense lower altitudes of the atmosphere.

0956 GMT (4:56 a.m. EST; 1:56 a.m. PST)

T+plus 30 seconds. Taurus has passed Mach 1, now traveling faster than the speed of sound as it heads south toward a polar orbit on the power of the Castor 120 first stage motor.

0955:30 GMT (4:55:30 a.m. EST; 1:55:30 a.m. PST)

LIFTOFF! Liftoff of the Orbital Sciences Taurus XL rocket and the Orbiting Carbon Observatory to study man's impact on the home planet.

0955:00 GMT (4:55:00 a.m. EST; 1:55:00 a.m. PST)

T-minus 30 seconds. All remains "go" for launch.

0954:30 GMT (4:54:30 a.m. EST; 1:54:30 a.m. PST)

T-minus 1 minute and counting to launch of NASA's first environmental satellite dedicated to mapping atmospheric carbon dioxide.

0954:00 GMT (4:54:00 a.m. EST; 1:54:00 a.m. PST)

T-minus 90 seconds. Auto sequence start.

0953:30 GMT (4:53:30 a.m. EST; 1:53:30 a.m. PST)

T-minus 2 minutes and counting. Final arming of the rocket has been completed after some initial difficulty.

0952:30 GMT (4:52:30 a.m. EST; 1:52:30 a.m. PST)

T-minus 3 minutes and counting. Launch team is working a problem arming the rocket.

0950:30 GMT (4:50:30 a.m. EST; 1:50:30 a.m. PST)

T-minus 5 minutes and counting. Orbital Sciences' launch conductor Adam Lewis has performed his "final clear to launch" readiness poll. Everyone voiced a "go" to launch at 1:55 a.m. local time.

0950:00 GMT (4:50:00 a.m. EST; 1:50:00 a.m. PST)

T-minus 5 minutes, 30 seconds. The rocket's rate gyro guidance system has been started.

0949:30 GMT (4:49:30 a.m. EST; 1:49:30 a.m. PST)

T-minus 6 minutes and counting. The S-band data transmitters have been turned on. And engineers confirm telemetry streaming from the rocket's systems is being received.

0947:30 GMT (4:47:30 a.m. EST; 1:47:30 a.m. PST)

T-minus 8 minutes and counting. The Taurus rocket's avoinics are going to internal power for launch.

0945:30 GMT (4:45:30 a.m. EST; 1:45:30 a.m. PST)

T-minus 10 minutes and counting. OCO is running normally on internal power.

0944:30 GMT (4:44:30 a.m. EST; 1:44:30 a.m. PST)

T-minus 11 minutes and counting. The Orbiting Carbon Observatory spacecraft is switching to internal battery power for its ride into orbit.

0943:30 GMT (4:43:30 a.m. EST; 1:43:30 a.m. PST)

T-minus 12 minutes and counting. Clocks have resumed ticking after the planned 5-minute hold. Liftoff remains scheduled for 1:55:30 a.m. local time (4:55:30 a.m. EST; 0955:30 GMT).

0943 GMT (4:43 a.m. EST; 1:43 a.m. PST)

The launch team was just polled to give approval for switching Taurus' avionics to internal power.

0940 GMT (4:40 a.m. EST; 1:40 a.m. PST)

The brief delay in launch was needed to work through a range issue, NASA says.

0938 GMT (4:38 a.m. EST; 1:38 a.m. PST)

The countdown will remain in this hold an additional four minutes to sync up with the new launch time.

0937 GMT (4:37 a.m. EST; 1:37 a.m. PST)

NEW LAUNCH TIME. The launch has been pushed back a few minutes to 1:55:30 a.m. local (4:55:30 a.m. EST; 0955:30 GMT).

0934 GMT (4:34 a.m. EST; 1:34 a.m. PST)

T-minus 12 minutes and holding. The countdown has entered the second of two planned built-in holds. This pause will last 5 minutes.

Everything is progressing for an on-time launch of the Taurus XL rocket from the Space Launch Complex 576E pad at Vandenberg Air Force Base in California.

0932 GMT (4:32 a.m. EST; 1:32 a.m. PST)

NASA launch director Chuck Dovale has conducted a final poll of the agency team. All elements remain ready for launch.

0928 GMT (4:28 a.m. EST; 1:28 a.m. PST)

Checks of the safety system have been conducted successfully.

0925 GMT (4:25 a.m. EST; 1:25 a.m. PST)

The Flight Termination System is switching to internal power for pre-launch checks.

0922 GMT (4:22 a.m. EST; 1:22 a.m. PST)

The launch team has been given a "go" to power on the rocket's Flight Termination System. This is the safety system that would be used in the unlikely event the rocket experiences a malfunction during launch.

0916 GMT (4:16 a.m. EST; 1:16 a.m. PST)

Upper level winds have been confirmed acceptable for the Taurus rocket's ascent today.

0911 GMT (4:11 a.m. EST; 1:11 a.m. PST)

Now 40 minutes from liftoff.

Tonight's mission is the first time a NASA satellite has been the primary payload aboard a Taurus rocket. The Orbital Sciences vehicle underwent the space agency's rigorous review to be qualified for launching a spacecraft such as the Orbiting Carbon Observatory.

"We had to go through a certification process with NASA," said John Brunschwyler, Orbital's Taurus program manager. "This process is where NASA investigates and assesses the design of the Taurus vehicle, our components, the processes to ensure it's the lowest risk possible for these valuable payloads."

A special sticker noting the Taurus' certification is affixed to the OCO rocket.

Taurus joins other certified rockets such as Orbital's air-launched Pegasus and United Launch Alliance's Delta 2 and Atlas 5 boosters.

"We're proud to say that Taurus has joined the elite family of vehicles certified by NASA," said Chuck Dovale, NASA's senior launch director.

Another Taurus is scheduled to launch NASA's Glory satellite later this year from Vandenberg to study aerosols in the atmosphere.

0908 GMT (4:08 a.m. EST; 1:08 a.m. PST)

The launch weather officer provided another briefing to management. There's still a 100 percent chance of acceptable conditions today.

The revised forecast for launch time predicts a few stratus clouds between 100 and 500 feet associated with patchy fog, scattered clouds from 2,500 to 5,000 feet, visibility of 5 miles, northeasterly winds of 5-10 knots and a temperature of 50 degrees F.

0903 GMT (4:03 a.m. EST; 1:03 a.m. PST)

The SIGI flight computer is reported "nav ready."

0857 GMT (3:57 a.m. EST; 12:57 a.m. PST)

Alignment of the Taurus rocket's guidance computer is beginning.

0856 GMT (3:56 a.m. EST; 12:56 a.m. PST)

T-minus 50 minutes and counting. Clocks have resumed ticking after the planned 15-minute hold. Liftoff remains scheduled for 1:51:30 a.m. local time (4:51:30 a.m. EST; 0951:30 GMT).

0854 GMT (3:54 a.m. EST; 12:54 a.m. PST)

Orbital Sciences' launch conductor Adam Lewis has performed his readiness poll for picking up the countdown.

"Launch team is ready to proceed with Hot Count," Lewis said.

0851 GMT (3:51 a.m. EST; 12:51 a.m. PST)

NASA launch director Chuck Dovale has polled the agency team to confirm there are no constraints with restarting the countdown following the built-in hold.

"OCO and the team are ready for Hot Count," Dovale reported.

0842 GMT (3:42 a.m. EST; 12:42 a.m. PST)

The Taurus avionics just switched from ground-fed power to internal power for a few moments so the launch team could verify voltages and currents. No problems with the power system were reported.

0841 GMT (3:41 a.m. EST; 12:41 a.m. PST)

T-minus 50 minutes and holding. The countdown has entered the first of two planned built-in holds. This pause will last 15 minutes.

These holds are designed to give the launch team a chance to deal with any problems and catch up on work that could be running behind schedule.

0837 GMT (3:37 a.m. EST; 12:37 a.m. PST)

The S-band data and C-band tracking checks were completely satisfactorly.

0831 GMT (3:31 a.m. EST; 12:31 a.m. PST)

Nestled inside the Taurus rocket's nose cone is the Orbiting Carbon Observatory, an experimental spacecraft as part of NASA's Earth System Science Pathfinder Program. It is the agency's first environmental satellite dedicated to mapping atmospheric carbon dioxide.

The 986-pound satellite was built by Orbital Sciences Corp. It stands 7 feet tall and 3 feet wide. A pair of power-generating solar wings will be deployed in space to span 29 feet tip-to-tip.

0821 GMT (3:21 a.m. EST; 12:21 a.m. PST)

Now 90 minutes from launch. Interrogation checks of the rocket's tracking beacon and telemetry data links are underway.

0809 GMT (3:09 a.m. EST; 12:09 a.m. PST)

The flight computer is booting.

0808 GMT (3:08 a.m. EST; 12:08 a.m. PST)

The rocket's avionics have been powered up and telemetry being received confirms good voltage and current readings.

0753 GMT (2:53 a.m. EST; 11:53 p.m. PST)

Just inside two hours from liftoff. The ground team has completed its final launch site configuration checklist. Powerup of the Taurus rocket will be accomplished shortly.

0747 GMT (2:47 a.m. EST; 11:47 p.m. PST)

Space Launch Complex 576E has been cleared of all workers for the remainder of the countdown.

0731 GMT (2:31 a.m. EST; 11:31 p.m. PST)

T-minus 2 hours and counting. Clocks are ticking toward liftoff of the Taurus XL rocket. Tonight's countdown includes a pair of planned hold points totaling 20 minutes in duration, leading toward the target liftoff time of 1:51:30 a.m. PST.

0725 GMT (2:25 a.m. EST; 11:25 p.m. PST)

There's no weather worries going into tonight's launch attempt.

The latest launch time forecast calls for a few stratus clouds between 100 and 500 feet associated with patchy fog, scattered clouds from 2,500 to 5,000 feet, visibility of 4 miles, northeasterly winds of 5-10 knots and a temperature in the upper 40s F.

0715 GMT (2:15 a.m. EST; 11:15 p.m. PST)

In this point in the countdown, the teams are working through the facility and range setup checklists.

0700 GMT (2:00 a.m. EST; 11:00 p.m. PST)

The early portion of tonight's countdown is progressing as planned and launch of the Taurus rocket remains on schedule for 1:51:30 a.m. local time (4:51:30 a.m. EST; 0951:30 GMT).

0600 GMT (1:00 a.m. EST; 10:00 p.m. PST)

Mission managers and the launch crew have reported for duty for the overnight flight of the Taurus XL rocket carrying the Orbiting Carbon Observatory from Vandenberg Air Force Base in California.

Final launch preparations are underway at the SLC-576E pad as workers finish configuring the complex for the 1:51 a.m. liftoff.

The simplistic launch site does not have a mobile service gantry. So there's no tower rollback to deal with like other rocket launches.

And this is a solid-propellant vehicle. So no fueling operations are conducted during the countdown.

0200 GMT (9:00 p.m. EST; 6:00 p.m. PST)

We have posted a gallery of photos taken Monday. The images show workers putting the final touches on the Orbital Sciences Taurus XL rocket at Vandenberg Air Force Base in preparation to launch NASA's Orbiting Carbon Observatory.

MONDAY, FEBRUARY 23, 2009

Weather forecasters are predicting a 100 chance that conditions will allow an Orbital Sciences Taurus rocket to launch the Orbiting Carbon Observatory from California early Tuesday morning.

"Tonight my team and I are going to continuously monitor the weather to ensure a safe launch and flight of the Taurus vehicle and the OCO payload. It's always especially rewarding for us as a team of meteorologists to aid on a launch of an environmental satellite," said Capt. Damon Vorhees, the launch weather officer from the 30th Weather Squadron at Vandenberg Air Force Base.

At launch time, the forecast calls for scattered clouds at 2,500 feet, some high cirrus clouds, light fog reducing visibility to 5 miles, northwesterly winds of 8-12 knots and a temperature in the upper 40s F.

"That is favorable weather for the launch and the probability of violating one of the launch rules tonight looks like it's going to be about zero percent," Vorhees said.

The OCO satellite will operate at least two years surveying the planet for natural and man-made carbon dioxide emissions.

"All of us are sincerely excited about not only the launch but of the important science data return in the months and years to come," said Ralph Basilio, OCO deputy project manager from the Jet Propulsion Laboratory.

The launch crew is resting today in preparation for the overnight countdown.

"The team is thrilled. They've done a tremendous amount of work to get to this point," said Chuck Dovale, NASA's senior launch director. "We're ready for launch. All of our reviews are complete."

Liftoff is targeted for exactly 1:51:30 a.m. local time (4:51:30 a.m. EST; 0951:30 GMT).

The day's launch window extends just four minutes and 20 seconds.

SUNDAY, FEBRUARY 22, 2009

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.

WEDNESDAY, FEBRUARY 18, 2009

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!