BY STEPHEN CLARK

Follow the launch of the Ariane 5 rocket with the European Space Agency's Herschel and Planck spacecraft. Reload this page for updates.

THURSDAY, MAY 14, 2009

An Ariane 5 launcher rocketed through blue skies and into space Thursday with two European telescopes designed to give scientists unprecedented views of star birth and the relic light from the Big Bang.

Read our full story.

1408 GMT (10:08 a.m. EDT)

Herschel and Planck are on their way to deep space after a successful launch from South America this morning.

The Ariane 5 rocket blasted off at 1312 GMT (9:12 a.m. EDT; 10:12 a.m. local time) from Kourou, French Guiana. The launcher deployed both satellites less than a half-hour later, and controllers in Germany acquired signals from the payloads about 20 minutes ago.

Check back later for a full launch report.

1400 GMT (10:00 a.m. EDT)

Today's launch has been called "perfect" by Jean-Yves Le Gall. Officials just wrapped up their post-launch speeches in Kourou.

Controllers at ESOC in Germany continue to evaluate the health of Herschel and Planck after today's launch.

1350 GMT (9:50 a.m. EDT)

Acquisition of signal! Ground stations in Western Australia have made contact with Herschel and Planck, confirming they have survived this morning's launch.

1347 GMT (9:47 a.m. EDT)

Today's launch was the 30th consecutive success for the Ariane 5 rocket.

1345 GMT (9:45 a.m. EDT)

Jean-Yves Le Gall, Arianespace's chairman and CEO, says the Ariane 5 launch was a success and put the spacecraft on course for arrival at the L2 point.

Officials expect to acquire the first signals from the spacecraft around 1349 GMT (9:49 a.m. EDT) from ground stations in Western Australia. This will confirm the spacecraft are in good shape following today's launch.

1342 GMT (9:42 a.m. EDT)

It appears everything has gone according to plan with this morning's launch. Handshakes, hugs and smiles all around the Jupiter Control Center in Kourou and ESOC in Germany.

1340 GMT (9:40 a.m. EDT)

Plus+28 minutes, 28 seconds. PLANCK SEPARATION! The Planck spacecraft is now free from the Ariane 5 rocket to begin a journey 1 million miles from Earth to take a picture of the infant universe.

1339 GMT (9:39 a.m. EDT)

Plus+27 minutes, 25 seconds. The Sylda 5 has been jettisoned. One more key milestone remains in this launch, the separation of Planck at Plus+28 minutes, 29 seconds.

1338 GMT (9:38 a.m. EDT)

Plus+25 minutes, 58 seconds. HERSCHEL SEPARATION! The Herschel infrared observatory has been released from the Ariane 5 rocket to begin a three-year mission studying the formation and evolution of stars and galaxies.

Next up will be the jettison of the Ariane's Sylda 5 dual payload adapter to reveal Planck, which is directly attached to the rocket's upper stage.

1337 GMT (9:37 a.m. EDT)

Plus+25 minutes. The Herschel telescope will be deployed at Plus+25 minutes, 58 seconds.

1336 GMT (9:36 a.m. EDT)

Plus+24 minutes, 35 seconds. Second stage shutdown. The Ariane 5's upper stage has ended its burn, concluding the powered flight portion of this morning's launch.

1336 GMT (9:36 a.m. EDT)

Plus+24 minutes. Approaching shut down of the upper stage. Altitude is 768 km, velocity is 9.8 km/sec.

1335 GMT (9:35 a.m. EDT)

Plus+23 minutes. The rocket is now passing over a tracking station in Malindi, Kenya.

1334 GMT (9:34 a.m. EDT)

Plus+22 minutes. Cutoff of the upper stage's HM7B engine is scheduled for Plus+24 minutes, 29 seconds. The rocket should be in an orbit with an apogee of 741,682 miles, a perigee of 168 miles and an inclination of 6 degrees.

1332 GMT (9:32 a.m. EDT)

Plus+20 minutes. Altitude is 324 km, velocity is 9.1 km/sec.

1330 GMT (9:30 a.m. EDT)

Plus+18 minutes. The rocket should now be communicating through a tracking station in Libreville, Gabon.

1329 GMT (9:29 a.m. EDT)

Plus+17 minutes. The Ariane 5's upper stage is shooting for an injection velocity of 9.967 kilometers per second, or about 22,296 mph. Altitude is now 185 km, velocity is 8.5 km/sec.

1328 GMT (9:28 a.m. EDT)

Plus+16 minutes. Altitude is 167 km, velocity is 8.3 km/sec.

1326 GMT (9:26 a.m. EDT)

Plus+14 minutes. The rocket is now passing within range of a tracking station on Ascension Island in the South Atlantic Ocean.

1325 GMT (9:25 a.m. EDT)

Plus+13 minutes. The HM7B engine, previously used by Arianespace's workhorse Ariane 4 launcher, continues to guide the rocket toward orbit. The engine burns liquid hydrogen and liquid oxygen propellants.

1323 GMT (9:23 a.m. EDT)

Plus+11 minutes. Altitude is 182 km, velocity is 7.4 km/sec.

1322 GMT (9:22 a.m. EDT)

Plus+10 minutes. Altitude is 195 km, velocity is 7.2 km/sec.

1321 GMT (9:21 a.m. EDT)

Plus+9 minutes, 15 seconds. The first stage's Vulcain 2 main engine has cut off. The spent stage has separated for its fall back into the atmosphere to burn up over the Atlantic Ocean. And cryogenic upper stage's HM7B engine has ignited to begin a burn lasting 15 minutes, 24 seconds.

1320 GMT (9:20 a.m. EDT)

Plus+8 minutes. About one minute away from shutdown of the first stage's Vulcain 2 engine. Altitude is 221 km, velocity is 5.7 km/sec.

1319 GMT (9:19 a.m. EDT)

Plus+7 minutes. The rocket's signal should now be acquired by the Natal tracking station in Brazil.

1318 GMT (9:18 a.m. EDT)

Plus+6 minutes, 15 seconds . Altitude is 206 km, velocity is 3.8 km/sec. The rocket is flying through the portion of the launch in which its trajectory levels out in order to gain speed.

1317 GMT (9:17 a.m. EDT)

Plus+5 minutes, 15 seconds. Altitude is 184 km, velocity is 3.2 km/sec.

1316 GMT (9:16 a.m. EDT)

Plus+4 minutes, 10 seconds. The protective payload fairing enclosing the Herschel and Planck payloads has separated from the rocket.

1315 GMT (9:15 a.m. EDT)

Plus+3 minutes, 30 seconds. The Ariane 5's payload fairing will be released at Plus+4 minutes, 3 seconds. Flight designers delayed the jettison to give extra protection to the sensitive Herschel telescope.

1315 GMT (9:15 a.m. EDT)

Plus+3 minutes. Altitude is 105 km, velocity is 2.2 km/sec.

1314 GMT (9:14 a.m. EDT)

Plus+2 minutes, 30 seconds. Both solid rocket boosters have been jettisoned from the vehicle. The first stage's hydrogen-fueled Vulcain 2 engine continues to push the rocket toward space.

1314 GMT (9:14 a.m. EDT)

Plus+2 minutes. The two solid rocket boosters are nearing the end of their burn to propel the 166-foot-tall rocket through the lower atmosphere.

1313 GMT (9:13 a.m. EDT)

Plus+1 minute, 30 seconds. Altitude is 27 km, velocity is 1.0 km/sec.

1313 GMT (9:13 a.m. EDT)

Plus+60 seconds. The Ariane 5 rocket is roaring through mostly sunny skies above the launch site in Kourou, French Guiana. The rocket has gone transonic and nearing maximum aerodynamic pressure.

1312 GMT (9:12 a.m. EDT)

Plus+30 seconds. The Ariane 5 has completed its pitch and roll maneuvers to fly east from the Guiana Space Center along South America's northeast coast.

1312 GMT (9:12 a.m. EDT)

LIFTOFF! Liftoff of the Ariane 5 rocket with Herschel and Planck, two telescopes that will push the boundaries of astronomy to look deep into the cold, distant universe!

1311 GMT (9:11 a.m. EDT)

Minus-30 seconds.

1311 GMT (9:11 a.m. EDT)

Minus-1 minute. The Ariane 5 rocket is being switched to internal power and the launcher's second stage is now at flight pressure.

A fast-paced series of events leading to launch will begin at Minus-37 seconds when the automated ignition sequence is started. The water suppression system at the launch pad will start at Minus-30 seconds. At Minus-22 seconds, overall control will be given to the onboard computer. The Vulcain 2 main engine will be readied for ignition with hydrogen chilldown starting at Minus-18 seconds. The residual hydrogen burn flares will fire beneath the Vulcain engine at Minus-6 seconds to burn away any free hydrogen gas. The cryogenic fueling arm is also retracted at Minus-6 seconds.

At Minus-3 seconds, onboard systems take over and the two inertial guidance systems go to flight mode. The rocket's navigation, guidance and attitude control functions are also activated. Vulcain 2 main engine ignition occurs at Minus-0 seconds with checkout between Plus+4 and Plus+7 seconds. If there are no problems found, the solid rocket boosters are ignited at Plus+7.0 seconds for liftoff at Plus+7.3 seconds.

1310 GMT (9:10 a.m. EDT)

Minus-2 minutes and counting. The Vulcain 2 engine supply valves are being opened, and the ground valves for engine chilldown are being closed. Electric heaters for the rocket's batteries and the Vulcain 2 ignition system are being turned off.

1309 GMT (9:09 a.m. EDT)

Minus-3 minutes and counting. The scheduled launch time has been loaded into the rocket's main computer system. The upper stage's liquid hydrogen system is now topped off and the tank is being transitioned to flight pressure. The main stage tank pressures should also now be at flight level.

1308 GMT (9:08 a.m. EDT)

Minus-4 minutes and counting. Pressurization is now underway for the main cryogenic stage's liquid oxygen and hydrogen tanks. Also, final pyrotechnic arming is starting.

1307 GMT (9:07 a.m. EDT)

Minus-5 minutes and counting. Nothing is standing in the way of liftoff at the opening of this morning's window.

1306 GMT (9:06 a.m. EDT)

Minus-6 minutes and counting. Liquid hydrogen and liquid oxygen supplies of the main cryogenic stage are being verified at flight level. Also, the pyrotechnic line safety barriers are being armed.

1305 GMT (9:05 a.m. EDT)

Minus-6 minutes, 30 seconds and counting. Officials are confirming the readiness of the Ariane 5's two scientific payloads and their ground segment.

1305 GMT (9:05 a.m. EDT)

Minus-7 minutes and counting. The synchronized sequence has started. Computers are now in control of this automated final phase of the launch countdown to prepare the rocket and ground systems for liftoff. There are three computers running the countdown -- one aboard the Ariane 5 and two redundant computers at the ELA-3 launch complex.

1304 GMT (9:04 a.m. EDT)

Minus-8 minutes. One minute away from the beginning of the synchronized sequence. Everything remains green on the main status board.

1302 GMT (9:02 a.m. EDT)

Minus-10 minutes. This mission is a rare morning launch for the Ariane 5, which typically launches during the afternoon or evening hours on flights with commercial communications satellites.

This morning's window was calculated to optimize the trajectory of Herschel and Planck to their operating post at the L2 point in deep space.

1301 GMT (9:01 a.m. EDT)

Minus-11 minutes. The 4,235-pound Planck spacecraft should now be running off of internal power.

Planck is riding in the lower position of the payload stack, tucked inside the Ariane's Sylda 5 dual payload adapter. The spacecraft stands about 13.8 feet tall and also has a diameter of about 13.8 feet. Thales Alenia Space of France was also its prime contractor.

The observatory will spend one-and-a-half years mapping the entire sky twice to detect tiny variations in the microwave background temperature of the universe. These temperature differences represent the structure of the universe when it was less than 400,000 years old.

1257 GMT (8:57 a.m. EDT)

Minus-15 minutes. The 7,500-pound Herschel observatory should now be running off of internal power.

Herschel is riding in the upper position inside the Ariane 5's payload fairing during this morning's launch. It is shaped like a tube, standing nearly 25 feet tall and stretching almost 15 feet across. Thales Alenia Space of France is the spacecraft's prime contractor.

The spacecraft includes a 3.5-meter, or 11.5-foot, mirror and three instruments to study distant cold pockets in the universe where stars are just beginning to form.

1252 GMT (8:52 a.m. EDT)

Minus-20 minutes. In the next few minutes, engineers will transition the Herschel and Planck payloads to internal power.

The status board in the Jupiter Control Center is showing all parameters remain green, indicating everything remains "go" for an on-time launch at 1312 GMT (9:12 a.m. EDT; 10:12 a.m. local time).

This morning's launch window extends for 55 minutes until 1407 GMT (10:07 a.m. EDT; 11:07 a.m. local time).

1247 GMT (8:47 a.m. EDT)

Minus-25 minutes. Today's launch will be the 188th launch of Europe's Ariane rocket family dating back Christmas Eve of 1979, the 44th flight of the heavy-lifting Ariane 5 rocket, and the second Arianespace mission this year.

The Ariane 5 rocket has 39 successful missions to its credit, including the last 29 consecutive flights since 2002. If all goes well this morning, this would mark the rocket's 40th success and 30th in a row.

1227 GMT (8:27 a.m. EDT)

Minus-45 minutes. Everything is on track for an on-time launch at 1312 GMT (9:12 a.m. EDT; 10:12 a.m. local time) from Kourou, French Guiana.

After liftoff, the 166-foot-tall rocket will roll on an eastward trajectory from Kourou to traverse the Atlantic Ocean on the way to orbit. The Ariane 5 will follow a standard trajectory during the early portion of the launch.

Engineers delayed the jettison of the rocket's payload fairing nose cone by about 50 seconds to help protect the Herschel telescope.

Thomas Passvogel, project manager for the Herschel and Planck missions, explained the delayed fairing separation in an interview with Spaceflight Now:

"The fairing jettison will be a bit later than nominal because we want to protect the Herschel telescope to the maximum possibility. It's launching at morning time in Kourou, so we are basically flying right into the sun. When we kick off the fairing, the telescope is not looking directly into the sun, but it is pointing very close to the sun. This was one of the reasons to delay the fairing jettison on Herschel, to be sure it doesn't look directly into the sun."

The cryogenic upper stage's HM7B engine will burn for more than 15 minutes to propel the payloads to a velocity of 22,296 mph. The Ariane 5 is shooting for an injection orbit with a low point of 168 miles, a high point of 741,682 miles and an inclination of 6 degrees.

Herschel separation is scheduled for Plus+25 minutes, 58 seconds.

"We then drift away after separation, and the upper stage makes a turn to avoid contact, then the Sylda 5 (adapter) is ejected. The launcher turns again to the side to avoid collision with that, then it spins up to 1 rpm and releases Planck," Passvogel said.

Planck separation is scheduled for Plus+28 minutes, 29 seconds.

"If everything is perfect during the injection, Ariane 5 will put us into a direct trajectory to L2. But clearly there is an uncertainty that you always have to bear in mind for the upper stage, so there is a launcher dispersion correction we can do if we need it," Passvogel said.

1212 GMT (8:12 a.m. EDT)

Minus-60 minutes. The launch team should have now completed a check of connections between the Ariane 5 rocket at ground telemetry, tracking and command systems.

1142 GMT (7:42 a.m. EDT)

Minus-90 minutes. Just an hour-and-a-half until the Herschel and Planck observatories will be on their way to space atop the powerful Ariane 5 booster. At this point in the countdown, filling of the liquid hydrogen and liquid oxygen tanks should be in the topping mode.

Coming up in about 20 minutes, continuity checks between the Ariane 5 rocket and the tracking, telemetry relay and commanding systems will be verified.

WEDNESDAY, MAY 13, 2009

A sleek white Ariane 5 rocket loaded with nearly $2.5 billion of ultra-sensitive astronomy equipment rolled to its launch pad in French Guiana Wednesday.

The 166-foot-tall launcher rolled to the pad from the final assembly building on dual rail tracks Wednesday. Engineers later made electrical and fluid connections between the heavy-lifting rocket and the ELA-3 launch zone.

Liftoff of the Ariane 5 ECA rocket from the Guiana Space Center is set for 1312 GMT (9:12 a.m. EDT) Thursday at the opening of a 55-minute launch window.

Forecasters are predicting mostly cloudy skies with a chance of showers during Thursday's launch window. Moderate winds are expected and the temperature will be around 80 degrees Fahrenheit, according to Meteo-France, the French weather service.

The Ariane 5, typically used to haul commercial communications satellites into orbit, will be launching two of Europe's most ambitious science missions in one go.

The Herschel telescope and the Planck observatory will study different parts of the distant, cold universe from a post nearly 1 million miles from the night side of Earth.

See our comprehensive Herschel and Planck preview stories for more details.

With a combined launch mass of 11,733 pounds, the two spacecraft are too massive to be launched together on any other booster. And it would be too expensive to fly the missions on different Ariane 5 rockets, according to Thomas Passvogel, the Herschel and Planck project manager at the European Space Agency.

The missions carry a combined cost of nearly $2.5 billion, making the flight one of the most expensive launches in recent history.

A lot is riding on the success of Thursday's launch, but ESA concluded it was worth the risk after an exhaustive survey of factors that could bring down the mission, Passvogel said.

The Ariane 5 is riding a streak of 29 straight successful launches dating back to 2002.

"Looking back at the recent Ariane 5 launches, I think we have to be realistic of the nominal risk to be taken on the dual launch," Passvogel said. "But it's true, putting both (spacecraft) on one launcher is increasing the risk."

In addition to ESA's multi-billion-dollar investment, scientists would lose decades of hard work to prepare for the missions, if the spacecraft were lost.

Scientists began studying a mission like Herschel in the early 1980s, and Planck's development started in 1994.

But officials expect everything will go as planned during Thursday's launch.

"I'm trying to avoid getting too excited and trying to stay cool," Passvogel said. "It's so exciting that it's difficult to stay cool. I think most of the work to come needs a cool hand and good organization."

Managers completed the Ariane 5's launch readiness review Saturday and another final closeout meeting Tuesday to declare the mission was ready for flight.

The final countdown is scheduled to commence at 0142 GMT Thursday (9:42 p.m. EDT Wednesday).

Launch controllers will begin testing the Ariane 5's electrical systems and configuring the rocket's first stage for fueling at 0542 GMT (1:42 a.m. EDT).

Six hours before liftoff, at 0712 GMT (3:12 a.m. EDT), workers will begin preparing the launch pad for the final countdown. Controllers will also load flight software into the Ariane 5's computer, test radio frequency links between the rocket and ground antennas, and align the the rocket's inertial guidance units.

The ELA-3 launch pad will be cleared of personnel by 0812 GMT (4:12 a.m. EDT). Fueling of the rocket's first stage with cryogenic liquid hydrogen and liquid oxygen, along with pressurization of both stages' attitude control systems, should begin about 10 minutes later.

The fueling sequence begins with pressurization of ground propellant tanks and chilldown of cross-country lines leading to the rocket. It will take about two hours to load 55,000 pounds of liquid hydrogen and 330,000 pounds of liquid oxygen into the rocket. Topping of the fuel tanks will continue until the final minutes before launch as the propellant naturally boils off.

Technicians will start a similar procedure at 0912 GMT (5:12 a.m. EDT) to load the Ariane 5's cryogenic upper stage with propellant.

Controllers will begin running small amounts of supercold propellant through plumbing in the Vulcain 2 first stage main engine at about 1012 GMT (6:12 a.m. EDT). The chilldown sequence helps cool down the piping to lessen the shock the engine will experience from the frigid fuel.

Both stages should be full and in topping mode by 1112 GMT (7:12 a.m. EDT).

The final synchronized launch sequence will be prepared 30 minutes before liftoff at 1242 GMT (8:42 a.m. EDT). The European Space Operations Center in Germany will also give its "go" or "no go" for launch at this time.

Herschel will be transitioned to internal power about 15 minutes prior to launch and Planck will be running off of internal power by the 11-minute point in the countdown.

Computers will begin controlling the countdown about seven minutes prior to launch. The synchronized launch sequence governs a fast-paced series of automated events, including fuel tank pressurization, transitioning the rocket and payloads to internal power, and taking systems to flight mode.

The first stage Vulcain 2 engine will ignite as the countdown clock reaches zero. Computers will give the engine a health check before sending the command to ignite the Ariane 5's twin solid rocket boosters about seven seconds later, committing the rocket to flight.