martes, 21 de febrero de 2017

Historic launch pad back in service with thundering blastoff by SpaceX

Watch Falcon 9 lift off from Kennedy Space Center launch pad 39A on a space station resupply mission. The rocket’s first stage then returned to land at neighboring Cape Canaveral Air Force Station.


Credit: SpaceX

SpaceX sent a cargo capsule with nearly 5,500 pounds of experiments and supplies on a three-day trip to the International Space Station on Sunday, firing the automated spaceship through low-hanging clouds and into orbit from the same launch pad where Apollo astronauts began voyages to the moon.

A kerosene-fueled 213-foot-tall (65-meter) Falcon 9 rocket powered the cargo freighter into space, soaring on a northeasterly course from launch pad 39A at NASA’s Kennedy Space Center at 9:39 a.m. EST (1439 GMT) atop 1.7 million pounds of thrust.

A few minutes later, the first stage booster nailed an on-target landing back at Cape Canaveral in the first such return to the launch base in daylight.

The launch — the first SpaceX has conducted from pad 39A — was timed for the Dragon cargo carrier align its course with the orbital path of the space station.

The historic launch complex, situated about a half-mile (750 meters) from the Atlantic Ocean, was the departure point for 94 missions before Sunday.


Originally constructed in the 1960s for the Apollo moon program, pad 39A hosted 12 Saturn 5 blastoffs on test flights, all of the moon landing missions and the uncrewed launch of NASA’s Skylab space station from 1967 through 1973.

NASA’s fleet of space shuttles launched from the pad 82 times, including the first and last flights of the program in 1981 and 2011.

The launch pad has remained dormant since the last shuttle mission took off July 8, 2011, and SpaceX signed a 20-year lease to take over the facility as a commercially-operated launch complex in 2014.

“It was really awesome to see 39A roar back to life for the first time since the shuttle era, and it was extremely special that this first launch off of 39A was a Dragon mission for NASA heading to the space station,” said Jessica Jensen, a Dragon mission manager who spoke with reporters after Sunday’s launch.

Credit: Walter Scriptunas II / Scriptunas Imagem

NASA decided it no longer needed pad 39A after the shuttle’s retirement. Nearby launch pad 39B, previously built for Apollo and shuttle flights, will be home to NASA’s Space Launch System, a government-owned heavy-lift rocket that will launch astronaut crews on deep space expeditions.

“This pad would have just sat here and rusted away in the salt air had we not had the use agreement with SpaceX to continue to enable commercial operations for our nation,” said Bob Cabana, director of the Kennedy Space Center.

The concrete foundation of pad 39A dates back to the Apollo era of the 1960s, while the 347-foot-tall (106-meter) fixed service structure and lightning tower were emplaced before the first shuttle launch.

“It gives me a little bit of chills when I walk out there and see stuff that’s left over from Apollo,” said Hans Koenigsmann, SpaceX’s vice president of flight reliability.

Since SpaceX took over, changes to pad 39A have included the construction of the new rocket hangar outside the south gate to the facility, where space shuttles and Saturn 5 moon rockets arrived on top of tracked crawler-transporters after rollout from the nearby Vehicle Assembly Building.

The hangar can accommodate five Falcon 9 rocket cores at a time, according to SpaceX.

“We’ve taken good care of this pad during the refurbishment and the rebuild,” said Gwynne Shotwell, SpaceX’s president, in remarks to reporters at the launch site Friday. “We saved precious things that needed to be saved. We’ve upgraded things to make them usable in the contemporary era. It’s hard to express how excited I am to be here, just two-and-a-half years after we got the lease.”

SpaceX sped the pad to completion after a rocket explosion damaged the company’s other Cape Canaveral launch facility — Complex 40 a few miles to the south — and grounded Falcon 9 flights until the booster returned to service last month in a mission from California.

Other additions at the pad include the installation of RP-1 kerosene fuel tanks and the construction of the massive transporter-erector, which is sized to accommodate SpaceX’s powerful triple-body Falcon Heavy rocket when it debuts later this year.

An access arm to allow astronauts to board SpaceX’s Crew Dragon capsule, a human-rated ship in development to launch people as soon as next year, will be added to pad 39A in the coming months.

SpaceX tested many of the launch pad’s new parts Feb. 12 during a countdown rehearsal in which the Falcon 9 rocket was fueled before a hold-down engine firing.

Engineers returned the two-stage launcher to SpaceX’s hangar, added the Dragon spacecraft, then rolled the fully-assembled vehicle back to the pad Thursday for further tests and the loading of final cargo.

But some features of the launch pad — like the quick partial retraction of the transporter-erector “strongback” umbilical tower at liftoff — were not been exercised until Sunday.

“This is a huge deal for us,” Jensen said. “We completely modernized the way the pad is built, so yeah, it’s super exciting, and you’re always a little bit nervous. We’ve run tons of tests to ensure that the hold-downs released properly, and the strongback throws back in a different way than it used to at pad 40.

“We’ve had tons of ground tests, but we’ve never mated an actual rocket with a payload on top for that,” she added. “So to watch it happen for the first time was just amazing.”

The mission’s takeoff was delayed from Saturday after SpaceX managers ordered a last-minute abort to investigate unexpected readings from the Falcon 9 upper stage engine’s backup steering mechanism.

Ground crews lowered the rocket at pad 39A overnight to replace parts of a redundant actuator on the second stage’s Merlin engine thrust vector control system, which directs the powerplant’s thrust to point the launcher in the right direction.

The rocket was raised upright again around six hours before launch, and the SpaceX launch team, working from a control center around 13 miles (21 kilometers) to the south, oversaw filling of the Falcon 9 with super-chilled, densified kerosene and liquid oxygen propellants in the final hour of the countdown.

Scattered rain showers around the Kennedy Space Center threatened to hold up the launch, but all weather criteria toggled “green” in time for the day’s instantaneous launch opportunity.


Eight minutes after it blasted off, the Falcon 9’s first stage booster made a dramatic vertical landing at a recovery site around 9 miles (15 kilometers) south of pad 39A at Cape Canaveral Air Force Station, the first time a SpaceX rocket has touched down on land in daylight.

An overcast deck of clouds prohibited ideal viewing of the launch and return, but the rocket’s nine Merlin engines sent a wave of window-rattling sound across the spaceport on the trip up, and twin sonic booms heralded the booster’s final descent as it became visible to spectators just before touchdown.

SpaceX plans to inspect the landed rocket and prepare it for another flight some time in the future. The company now has eight flown first stage boosters in its inventory, recovered after landings at Cape Canaveral and at sea. Seven of those are considered flight-worthy, according to Jensen.

The SES 10 satellite, a commercial broadcasting spacecraft, is in Cape Canaveral preparing for a launch on a Falcon 9 rocket in March that will fly with a previously-used first stage booster for the first time.

Once in orbit, the Dragon supply freighter unfurled two power-generating solar array wings to a span of 54 feet (16 meters). The spacecraft was scheduled to open a navigation bay later Sunday and fine-tune its course toward the space station with a series of thruster firings ahead of its arrival at the outpost early Wednesday.

French-born European Space Agency flight engineer Thomas Pesquet will grapple the approaching cargo craft around 6 a.m. EST (1100 GMT) Wednesday with the space station’s robotic arm after the automated ship flies within about 30 feet, or 10 meters, of the research complex.

The Canadian-built robot arm, under the command of ground controllers in Houston, will transfer the gumdrop-shaped logistics freighter to a berthing port on the station’s Harmony module a few hours later.

Once bolts drive closed to firmly connect the SpaceX cargo craft to the space station, astronauts inside the orbiting science lab will open hatches and begin unpacking the 3,373 pounds (1,530 kilograms) of supplies, experiments and provisions inside.

Meanwhile, the robot arm and the station’s two-armed Dextre handyman will remove three payloads — totaling more than 2,100 pounds (more than 950 kilograms) — from the Dragon’s unpressurized trunk for placement on platforms on the outpost’s huge structural truss.


The Dragon spaceship deploys from the Falcon 9 rocket’s upper stage in orbit. Three unpressurized payloads are seen inside the Dragon capsule’s trunk. Credit: SpaceX


One of the payloads is NASA’s $92 million Stratospheric Aerosol and Gas Experiment 3, or SAGE 3, an ozone monitor that comes with a separate ESA-built “hexapod” mounting plate designed to point the instrument at Earth’s limb, or horizon, at sunset and moonset.

The sunlight and moonlight passing through the layers of the upper atmosphere will help tell scientists about the condition of the ozone layer and allow researchers to track pollutants and particles suspended high above Earth.

SAGE 3, developed by NASA’s Langley Research Center in Virginia, is the latest in a series of ozone measurement sensors developed by NASA since 1979. Previous space missions studying ozone showed a decline in the distribution of the gas over Earth’s poles, and researchers tied the ozone depletion to chlorofluorocarbon, a chemical used in cleaning agents, refrigeration and air conditioning.

An international treaty called the Montreal Protocol that went into force in 1989 banned chlorofluorocarbons, and scientists have observed the depletion stop and watched the ozone layer begin to recover.

“How does SAGE 3 fit into that? We’re going to make measurements from the space station that show the recovery is on track,” said Michael Cisewski, SAGE 3 project manager at NASA. “I think that, from a science perspective, it doesn’t get any better than that.”

“SAGE 3 will also measure other important stratospheric gases and atmospheric aerosols, which are components of pollution that also impact the radiation balance of our planet,” said Michael Freilich, director of NASA’s Earth science division.

The other experiment package carried inside the Dragon capsule’s external bay is sponsored by the U.S. military’s Space Test Program, hosting more than a dozen investigations for NASA and the Defense Department.

Among STP-H5’s investigations are NASA’s Raven autonomous space navigation demonstration designed to support future satellite servicing missions and NASA’s Lightning Imaging Sensor.

The Raven payload is made up of three sensors — optical, infrared and laser trackers — to autonomously follow visiting cargo vessels arriving and departing from the space station.


The Raven payload seen before launch. Credit: NASA/Goddard Space Flight Center

Benjamin Reed, deputy director of NASA’s satellite servicing program at Goddard Space Flight Center, called Raven a “three-eyed” instrument.

“The Raven module will be observing visiting vehicles as they approach in all three wavelengths,” Reed said. “We will be generating range, bearing and pose estimates of those visiting vehicles on-board with sophisticated algorithms and on-board processing, based on the input that the sensors are receiving.”

Raven is a follow-up to a NASA experiment that tried out satellite refueling techniques using a boilerplate test panel outside the space station.

The satellite servicing demonstrations will refine the technologies needed for future robotic missions to refuel, refurbish, upgrade and reposition satellites, beginning with NASA’s Restore-L spacecraft in development for launch in 2020 to gas up the aging Landsat 7 environmental observatory in orbit.

Raven will try out the navigation equipment needed for Restore-L, and missions like it, to approach another object in orbit without any input from the ground and latch on to it, even if the target was never designed for a docking.

Landsat 7 was launched in 1999 before any such refueling mission was ever proposed, so it is not equipped with markings or a docking port.

“These technologies are quite difficult, and that is why NASA is taking the lead, pushing the envelope, (and) doing the hard work first,” Reed said. “Once we have developed it on missions like Raven, we will then transfer that technology to U.S. industry that is interested in taking this on commercially.”

The Lightning Imaging Sensor, managed by NASA’s Marshall Space Flight Center in partnership with the University of Alabama in Huntsville, will take pictures and log lightning strikes from the space station’s perch nearly 250 miles (400 kilometers) above Earth.

Based on a spare camera made for the U.S.-Japanese Tropical Rainfall Measuring Mission, the instrument cost $7 million to refurbish and will detect lightning day and night in a belt between 56 degrees north and south latitude.

“Lightning actually occurs somewhere on Earth some 45 times every single second,” Freilich said. “Understanding the processes which cause lighting and the connections between lightning and subsequent severe weather events like convective storms and tornadoes … are keys to improving weather predictions and saving lives and property in this country and throughout the globe.”

A bevy of biological experiments are packed inside the Dragon supply ship.

Scientists are sending 40 mice into orbit to examine how bone fractures heal in the absence of gravity, and search for the biological reasons why most animals, including humans, cannot regrow lost limbs.

“We’re trying to understand what happens in the body as the bones start healing,” said Rasha Hammamieh, the rodent research project’s chief scientist from the U.S. Army Center for Environmental Health Research.

The military is co-sponsoring the bone health experiment, with an eye toward learning lessons that could be applied to helping injured soldiers recover from catastrophic bone injuries.

There are also implications for civilians, such as elderly patients with osteoporosis.

“Up in space, you lose bone,” said Melissa Kacena, co-investigator for the bone experiment and an associate professor of orthopedic surgery, anatomy and cell biology, and biomedical engineering at Indiana University. “In fact, astronauts lose about 1 to 3 percent of their bone density in a month. Someone with advanced osteoporosis loses closer to 1 percent per year.”

Kacena added that scientists want to test drugs on rodents that might be able to “rebuild your bone systematically, so it could have applications not only for bone healing, but also for osteoporosis.”

Astronauts on the space station will euthanize the mice and return them to Earth for comparison with a control group that remained on the ground.

Bacterial and stem cell researchers also had a stake in Sunday’s launch.

“We are excited to put MRSA, which is a superbug, on the International Space Station and investigate the effects of microgravity on the growth and mutation patterns of these bugs,” said Anita Goel, chairman and science director of Nanobiosym, which developed the experiment with the Center for the Advancement of Science in Space.

“I have this hypothesis that microgravity will accelerate the mutation patterns. If we can use microgravity as an accelerator to fast forward and get a sneak preview of what these mutations will look like, then we can esssentially build smarter drugs back on Earth.”

A science team led by a Mayo Clinic biologist is sending human adult stem cells to the space station, pursuing research that could help transplant patients and stroke victims.

“We know stem cells grow differently using simulated microgravity,” said Abba Zubair, medical and scientific director of the Cell Therapy Laboratory at the Mayo Clinic in Jacksonville, Florida. “Primarily, our focus is to see if microgravity actually can help stem cells to expand faster, so that we can grow more of them to bring back to use for human application.”

The Dragon spaceship will remain at the space station until around March 21, when it will detach and head for a re-entry and parachute-assisted splashdown in the Pacific Ocean, where SpaceX will safe the capsule, transfer it back to port, and begin removing the returned cargo.

The resupply mission is SpaceX’s tenth cargo launch to the space station. The company has two multibillion-dollar cargo contracts with NASA covering at least 26 round-trip missions.

SpaceX’s next launch is scheduled within the next two weeks — perhaps as soon as Feb. 28 — with the EchoStar 23 communications satellite. That flight will also blast off from pad 39A.

http://spaceflightnow.com

martes, 14 de febrero de 2017

Live coverage: European launcher heads to orbit from French Guiana

Live coverage of the countdown and launch of an Ariane 5 rocket with the Sky Brasil 1 and Telkom 3S communications satellites. Text updates will appear automatically below;



El flujo de video en vivo de Arianespace comienza aproximadamente a las 2120 GMT (4:20 p.m. EST).

02/14/2017 19:38

Thales Alenia Space confirms the Telkom 3S satellite is also sending telemetry to engineers on the ground. Both satellites launched tonight are functioning as intended in the early phases of their missions.

02/14/2017 19:32

Airbus Defense and Space confirms the Sky Brasil 1 satellite is in contact with ground controllers, verifying it's alive following tonight's blastoff.

02/14/2017 19:24

Arianespace has confirmed success on tonight's Ariane 5 launch.

"Arianespace is delighted to announce that Sky Brasil 1 and Telkom 3S have been separated as planned in the targeted geostationary transfer orbit," said Stephane Israel, chairman and CEO of Arianespace. "For the first time this year, and the 77th in a row, Ariane 5 has performed flawlessly, so well done and congratulations to all."

02/14/2017 19:21  Telkom 3S separation


Telkom 3S separation confirmed. The new satellite will offer television broadcasts, mobile backhaul and broadband services over Indonesia, Malaysia and Southeast Asia for up to 18 years.

02/14/2017 19:09

Plus+29 minutes, 30 seconds. The Sylda dual-payload adapter has jettisoned, setting the stage for separation of Telkom 3S at Plus+39 minutes, 43 seconds.

02/14/2017 19:08  Sky Brasil 1 separation


Separation of Sky Brasil 1 confirmed, beginning a 19-year mission for DirecTV Latin America.

The Ariane 5's Sylda 5 dual payload adapter will be separated next, revealing the Telkom 3S spacecraft for its deployment in a few minutes.

02/14/2017 19:05  Second stage cutoff


Plus+25 minutes, 20 seconds. The rocket's second stage shut down as scheduled. The upper stage is now maneuvering into the correct orientation for deployment of Sky Brasil 1.

02/14/2017 19:04

Plus+24 minutes. The rocket is surpassing a speed of 20,500 mph. Shutdown of the upper stage is about a minute-and-a-half from now. A tracking station in Malindi, Kenya, is now in contact with Ariane 5.

02/14/2017 19:02

Plus+22 minutes. The upper stage will shut down at Plus+25 minutes, 16 seconds, after reaching a target orbit with a low point of 155 miles, a high point of 22,205 miles, and an inclination of 4 degrees. The rocket is now being tracked by a ground station in Libreville, Gabon.

02/14/2017 18:58

Plus+18 minutes. Everything is going well with the burn of the upper stage HM7B engine as the Ariane 5 races across the Atlantic Ocean at 8.31 kilometers per second, or about 18,600 mph.

02/14/2017 18:54

Plus+14 minutes. This upper stage engine is about 5 minutes into a planned 16-minute burn. Ariane 5 is at an altitude of 151 kilometers. A tracking station on Ascension Island in the Atlantic Ocean has picked up signals from the Ariane 5.

02/14/2017 18:50

The Ariane 5 has passed over the horizon from Kourou and is now out of range of the Galliot tracking station near the launch pad.

02/14/2017 18:49  Staging


Plus+9 minutes, 15 seconds. The main cryogenic stage's Vulcain engine has cut off and the spent stage has separated. It will fall back into the atmosphere into the Atlantic Ocean off the west coast of Africa.

And the upper stage's HM7B engine is now firing to inject the Sky Brasil 1 and Telkom 3S satellites into orbit.

02/14/2017 18:47

Plus+7 minutes, 30 seconds. Altitude is 176 km, downrange distance is 1,040 km and velocity is 5.04 km/s.

02/14/2017 18:46  Launch image


02/14/2017 18:45

Plus+5 minutes, 20 seconds. Altitude is 161 km, downrange distance is 515 km and velocity is 3.25 km/s.

02/14/2017 18:43

Plus+3 minutes, 30 seconds. Separation of the rocket's nose cone has been confirmed. The Ariane 5 core stage will continue burning until about Plus+9 minutes into the mission.

02/14/2017 18:42

The solid rocket boosters have been jettisoned from the Ariane 5 rocket's core stage after consuming approximately 480 metric tons of propellant. The liquid-fueled Vulcain 2 main engine continues to fire to propel the vehicle and its satellite payload to space.

02/14/2017 18:41

The vehicle is on the proper heading as it rides the power of the twin solid rocket boosters and main stage liquid-fueled engine.

02/14/2017 18:40  Liftoff

Liftoff of an Ariane 5 rocket carrying Sky Brasil 1 and Telkom 3S, communications satellites heading for coverage zones over Brazil and Indonesia.

02/14/2017 18:38  Minus-60 seconds

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 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-5.5 seconds to burn away any free hydrogen gas. At Minus-4 seconds, onboard systems take over and the two inertial guidance systems go to flight mode. Vulcain main engine ignition occurs at Minus-0 seconds with checkout between Plus+4 and 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.

02/14/2017 18:38  Minus-2 minutes

The Vulcain main engine supply valves are being opened. And the ground valves for engine chilldown are being closed.

02/14/2017 18:36

The scheduled launch time has been loaded into the rocket's main computer system. The main stage tank pressures should now be at flight level.

02/14/2017 18:36

With the live broadcast back underway, pressurization has begun for the main cryogenic stage's liquid oxygen and hydrogen tanks. Also, final pyrotechnic arming is starting.

02/14/2017 18:35

Arianespace's webcast is again experiencing technical problems. We're awaiting the resumption of the live video stream from Kourou.

02/14/2017 18:34

Minus-5 minutes. All status panel lights remain green, indicating no problems right now that could prevent blastoff at 2139 GMT.

02/14/2017 18:34

Arianespace's webcast has resumed after experiencing technical difficulties.

02/14/2017 18:33

Minus-6 minutes. 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.

02/14/2017 18:33

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 launch complex.

The launch time is set for 2139:00 GMT (4:39:00 p.m. EST; 6:39 p.m. French Guiana time). Liftoff actually occurs even seconds later with ignition of the solid rocket boosters.

02/14/2017 18:32

Minus-8 minutes. The last weather briefing before the countdown enters the synchronized launch sequence indicates all parameters are acceptable for liftoff at 2139 GMT (4:39 p.m. EST).

02/14/2017 18:30

Minus-9 minutes. The Synchronized Sequence is being prepped for activation. This computer-run sequence assumes control of the countdown at the Minus-7 minute mark to perform the final tasks to place the rocket and pad systems in launch configuration.

At Minus-4 seconds, the rocket's onboard computer will take over control of main engine start, health checks of the powerplant and solid rocket booster ignition commanding for liftoff.

02/14/2017 18:29

Minus-10 minutes. Today's launch will deliver the Sky Brasil 1 and Telkom 3S communications satellites to an orbit targeting a planned high point of 22,205 miles, a targeted low point of 155 miles and an inclination of 4 degrees.

The satellites were built by Airbus Defense and Space and Thales Alenia Space, respectively, and will use their on-board engines to raise their orbits to maintain altitude nearly 22,300 miles over the equator.

The Sky Brasil 1 broadcasting satellite, occupying the upper position in the Ariane 5's dual-payload stack, will serve Brazilian markets with direct-to-home television programming for DirecTV Latin America, a subsidiary of AT&T.

Sky Brasil 1 will separate from the Ariane 5's second stage at T+plus 27 minutes, 25 seconds.

A Sylda 5 adapter will be discarded a few minutes later, revealing the 7,826-pound Telkom 3S spacecraft, the mission’s other satellite passenger.

Telkom 3S is designed to support video, data broadband and mobile telecom services over Indonesia, Malaysia and other parts of Southeast Asia for Telkom Indonesia. Separation of the Telkom 3S spacecraft from the Ariane 5 rocket is scheduled at T+plus 39 minutes, 43 seconds.

The payloads have a combined mass of approximately 23,109 pounds, or 10,482 kilograms, including the barrel-shaped Sylda dual-payload adapter.

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02/14/2017 18:24

Minus 15 minutes. All parameters continue to look good for launch in 15 minutes. A communications check between ground stations and the rocket has concluded.

Some statistics on today's flight:
  • 235th launch of an Ariane rocket since 1979
  • 285th Arianespace mission
  • 91st launch of an Ariane 5 rocket since 1996
  • 60th launch of an Ariane 5 ECA rocket since 2002
  • 66th flight of a Vulcan 2 engine
  • 192nd flight of an HM7B engine
  • 78th Ariane 5 launch targeting GTO
  • 10th AT&T/DirecTV satellite launched by Arianespace
  • 116th Airbus Defense and Space satellite launched by Arianespace
  • 3rd Telkom Indonesia satellite launched by Arianespace
  • 146th Thales Alenia Space satellite launched by Arianespace
  • 2nd launch from the Guiana Space Center in 2017
  • 1st Ariane 5 launch in 2017

02/14/2017 18:10

Minus-30 minutes. The Ariane 5's first and second stages are now loaded with cryogenic liquid hydrogen and liquid oxygen propellants.

The 17.7-foot-diameter first stage's Vulcain 2 engine burns 149.5 metric tons, or about 329,000 pounds, of liquid oxygen and 25 metric tons, or about 55,000 pounds, of liquid hydrogen. The cryogenic upper stage's HM7B engine consumes about 14.7 metric tons, or more than 32,000 pounds, of oxygen and hydrogen.

The fluids are stored at super-cold temperatures and naturally boil off in the warm tropical atmosphere in French Guiana. More propellant is slowly pumped into the rocket for most of the countdown to replenish the cryogenic fuel.

The topping sequence ends in the final few minutes of the countdown as the fuel tanks are pressurized and the fueling system is secured.

Built by a consortium of European contractors led by Airbus Safran Launchers in Vernon, France, the Vulcain 2 engine generates up to 300,000 pounds of thrust during its 9-minute firing. It burns about 320 kilograms, or 705 pounds, of liquid oxygen and liquid hydrogen propellant per second.

The engine's nozzle has an exit diameter of 2.1 meters, or about 6.9 feet. It weighs more than 4,600 pounds and its liquid oxygen and liquid hydrogen turbopumps spin at 12,300 rpm and 35,800 rpm, respectively.

The Vulcain 2 replaced the Vulcain engine used on the initial version of the Ariane 5. The newer engine produces 20 percent more thrust.

The Ariane 5's upper stage is powered by an HM7B engine, a modified version of the HM7 engine used on the upper stage of the Ariane 4 rocket. The 364-pound HM7B engine is manufactured by Airbus Safran Launchers in Ottobrunn, Germany.

The HM7B engine produces more than 14,500 pounds of thrust in vacuum.

The Ariane 5 configuration with a Vulcain 2 engine and HM7B-powered cryogenic upper stage is known as the Ariane 5 ECA.

The Ariane 5's twin solid rocket boosters are packed with propellant near the launch site in French Guiana before they are assembled and positioned on each side of the cryogenic core stage.

With the rocket now fully fueled for launch, the vehicle weighs 1.7 million pounds. At liftoff, the rocket produces 2.9 million pounds of thrust.

02/14/2017 17:39

Minus-60 minutes.

Track the major milestones on today's launch with this timeline of major flight events. Deployment of the Sky Brasil 1 and Telkom 3S satellites will occur within 40 minutes of liftoff.

02/14/2017 15:51


See photos of the Ariane 5 during yesterday's rollout to the pad, along with a few snapshots of the rocket after arriving in the ELA-3 launch zone.

02/14/2017 15:09

Minus-3 hours, 30 minutes. The Ariane 5 rocket's first stage, known by the French acronym EPC, is currently being filled with liquid oxygen and liquid hydrogen. The second stage, or ESC-A, is also receiving the same mix of liquid propellants. The first stage Vulcain 2 engine and the upper stage HM7B engine both consume the super-cold fuel.

The cryogenic propellant will be gradually pumped inside the rocket to maintain proper levels as the fuel evaporates over the rest of the countdown.

The Ariane 5's supply of cryogenic liquid helium, used to pressurize the rocket's propellant tanks, was loaded aboard the launcher Monday.

02/14/2017 07:23

The Ariane 5 countdown is officially getting underway in French Guiana with launch crews arriving at the space base to prep the rocket and ground systems for liftoff at 2139 GMT (4:39 p.m. EST; 6:39 p.m. local time).

The launch window extends for 86 minutes.

The 91st Ariane 5 mission will loft the Sky Brasil 1 and Telkom 3S communications satellites destined to provide TV, broadband and data services over Brazil and Indonesia.

Sky Brasil 1, manufactured by Airbus Defense and Space, is set to begin a mission broadcasting direct-to-home television programming to millions of homes and businesses in Brazil for DirecTV Latin America, a subsidiary of AT&T.

The more than 13,000-pound (6-metric ton) Sky Brasil 1 satellite, designed to function for up to 19 years, is mounted in the upper position of the Ariane 5 rocket's dual-payload stack. It is heading for a slot in geostationary orbit at 41.3 degrees west longitude.

The smaller of the two satellite passengers on Tuesday's flight is Telkom 3S, a 7,826-pound (3,550-kilogram) communications craft built by Thales Alenia Space and owned by Telkom Indonesia.

Telkom 3S will broadcast television signals, broadband Internet and mobile communications services over Indonesia, Malaysia and neighboring parts of Southeast Asia from a position in geostationary orbit nearly 22,300 miles (about 35,800 kilometers) above Earth's equator at 118 degrees east longitude.

Tuesday's launch will be the first Ariane 5 flight of the year, and Arianespace's second launch of 2017.

The countdown is due to begin at 1016 GMT (5:16 a.m. EST), with clocks programmed for liftoff of the Ariane 5 ECA rocket at 2139 GMT (4:39 p.m. EST), or 6:39 p.m. local time at the launch site in French Guiana.

A check of electrical systems occurred around 1106 GMT (6:06 a.m. EST).

Workers will also put finishing touches on the launch pad, including the closure of doors, removal of safety barriers and configuring fluid lines for fueling. The flight program for today's launch will be loaded into the rocket's computer.

The launch team will begin the process to fuel the rocket with super-cold liquid hydrogen and liquid oxygen propellants around 1716 GMT (12:16 p.m. EST). First, ground reservoirs will be pressurized, then the fuel lines will be chilled down to condition the plumbing for the flow of super-cold liquid hydrogen and liquid oxygen, which are stored at approximately minus 423 degrees Fahrenheit and minus 298 degrees Fahrenheit, respectively.

It will take approximately two hours to fill the Ariane 5 core stage tanks.

A similar procedure for the Ariane 5's cryogenic upper stage will commence at 1756 GMT (12:56 p.m. EST).

Chilldown conditioning of the Vulcain 2 first stage engine will occur at 1821 GMT (1:21 p.m. EST), and a communications check between the rocket and ground telemetry, tracking and command systems is scheduled for 2024 GMT (3:24 p.m. EST).

A final weather briefing will come at T-minus 10 minues, and then the computer-controlled synchronized countdown sequence will begin seven minutes before launch to pressurize propellant tanks, switch to on-board power and take the rocket's guidance system to flight mode.

The Vulcain 2 engine will ignite as the countdown clock reaches zero, followed by a health check and ignition of the Ariane 5's solid rocket boosters seven seconds later to send the 1.7 million-pound launcher skyward.

Five seconds after blastoff, the rocket will begin pitching east from the ELA-3 launch pad, surpassing the speed of sound less than a minute into the mission. The Ariane 5's twin solid rocket boosters will jettison 2 minutes, 20 seconds after liftoff.

Once above the dense atmosphere, the launcher's payload fairing will fall away at an altitude of more than 70 miles -- about 112 kilometers. The Ariane 5's first stage will shut down 8 minutes, 55 seconds after liftoff, followed moments later by stage separation and ignition of the hydrogen-fueled cryogenic HM7B upper stage engine.

The rocket's upper stage will fire for more than 16 minutes, accelerating to a velocity of 21,000 mph, or more than 9.3 kilometers per second, to reach an orbit with a planned high point of 35,736 kilometers (22,205 miles), a targeted low point of 250 kilometers (155 miles) and an inclination of 4 degrees.

The release of Sky Brasil 1 is scheduled for 27 minutes, 25 seconds, after liftoff. The rocket's barrel-shaped Sylda 5 dual-payload adapter will be jettisoned a few minutes later.

Telkom 3S will separate from the lower portion of the payload stack at 39 minutes, 43 seconds.

02/14/2017 06:06  Launch preview

Two commercial communications satellites heading for orbits more than 22,000 miles (36,000 kilometers) above Earth are scheduled for launch from a jungle launch facility in French Guiana at sunset Tuesday on top of an Ariane 5 rocket.

The Sky Brasil 1 and Telkom 3S spacecraft are mounted inside the Ariane 5's nose cone for launch at 2139 GMT (4:39 p.m. EST; 6:39 p.m. French Guiana time) Tuesday, just before sunset at the South American space base. The launch window extends for 86 minutes.

The 180-foot-tall (55-meter) Ariane 5 rocket rolled out to the launch pad around midday Monday, trekking along dual rail tracks 1.7 miles (2.7 kilometers) from the Guiana Space Center's final assembly building to the ELA-3 launch zone.

Fastened on a mobile launch table, the rocket was towed behind a diesel-powered Titan truck for the journey.

Technicians secured the rocket and its launch platform at the pad after completing the transfer Monday afternoon, connecting the Ariane 5 with the facility's propellant lines, electrical system and ground telemetry links ahead of the start of the final countdown Tuesday morning.

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