AEHF-4 - Atlas V 551 (AV-073) - CCAFS SLC-41 - 17.10.2018, 04:15 UTC

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10/17/2018 05:51 Stephen Clark

The chilldown sequence to thermally condition the Centaur stage's Aerojet Rocketdyne RL10C-1 engine has started.

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ULA‏Подлинная учетная запись @ulalaunch 1 мин. назад

Looks like YouTube is back up! http://bit.ly/av_aehf4 

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10:55 p.m. EDT (0255 UTC)

The launch team has received the "go" to begin filling the Centaur upper stage with the super-cold fuel following chilldown of the system. The Centaur holds about 12,300 gallons of the cryogenic propellant for its three engine burns during this launch.

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10/17/2018 06:00 Stephen Clark

There are no major weather concerns being monitored in the countdown, with clear skies over Cape Canaveral and no rain showers in the vicinity of the launch pad.

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NASA Nate‏ @NASA_Nerd 10 мин. назад

On-site at ITL Causeway for ULA's Atlas V 551 launch with AEHF-4. A beautiful night to go fly. – ITL causeway

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Tory Bruno‏Подлинная учетная запись @torybruno 2 мин. назад

T-45 min. The board is green. Looks like a good evening to go to space.
#AEHF4

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11:15 p.m. EDT (0315 UTC)

This is Atlas Launch Control with 60 minutes remaining in our countdown to liftoff at 12:15 a.m. EDT (0415 UTC). Today marks the 79th flight for Atlas 5 since debuting in August 2002. The vehicle has a 100 percent mission success record for the Defense Department, NASA, the National Reconnaissance Office and commercial customers.

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William Harwood‏ @cbs_spacenews 2 мин. назад

A5/AEHF4: Now 40 minutes to launch; no known issues and the weather appears ideal, with the moon and Mars setting in the west and Orion beginning to rise in the east; a gorgeous night on the Space Coast

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11:25 p.m. EDT (0325 UTC)

Fast-filling of the first stage liquid oxygen tank has been completed. Topping mode is now underway to give us a fully-fueled, 1.3-million-pound rocket for flight. The cryogenics will be replenished throughout the countdown until the final minutes before launch to replace the liquid oxygen and liquid hydrogen that naturally boils away.

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Michael Seeley‏ @Mike_Seeley 8 мин. назад

Behold, the mighty #AtlasV with the #AEHF4 satellite, ready to go.

The launch window opens at 12:15am (ET) Wednesday morning, in just under one hour.

Go Atlas, go AEHF4!

(Pic: me / @WeReportSpace )

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10/17/2018 06:30 Stephen Clark

45 minutes until launch. Here are some statistics on tonight's mission:

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• 661st launch for Atlas program since 1957
• 363rd Atlas launch from Cape Canaveral
• 250th mission of a Centaur upper stage
• 227th use of Centaur by an Atlas rocket
• 490th production RL10 engine to be launched
• 27th RL10C-1 engine launched
• 85th flight of an RD-180 main engine
• 106th-110th AJ-60 solid rocket boosters flown
• 79th launch of an Atlas 5 since 2002
• 29th U.S. Air Force use of an Atlas 5
• 64th launch of an Atlas 5 from Cape Canaveral
• 5th Atlas 5 launch of 2018
• 116th Evolved Expendable Launch Vehicle flight
• 131st United Launch Alliance flight overall
• 71st Atlas 5 under United Launch Alliance
• 93rd United Launch Alliance flight from Cape Canaveral
• 50th ULA launch for U.S. Air Force
• 26th 500-series flight of the Atlas 5
• 9th Atlas 5 to fly in the 551 configuration
• 91st launch from Complex 41
• 64th Atlas 5 to use Complex 41
• 17th launch overall from Cape Canaveral in 2018
  

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10/17/2018 06:34 Stephen Clark

Tonight's launch is the fourth Atlas 5 rocket flight to carry an Air Force AEHF communications satellite into orbit. But the previous three lifted off aboard different version of the Atlas 5 with three solid rocket boosters, while tonight's mission will be powered by five of the strap-on motors.

The extra boosters will give the Atlas 5 the capability to deliver the AEHF 4 satellite closer to its final perch in geostationary orbit, reducing the time and fuel needed for the spacecraft to maneuver into its operational orbit.

Here's a view of the AEHF 4 communications satellite last month before encapsulation inside the Atlas 5's payload fairing. (Credit: Lockheed Martin)

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11:35 p.m. EDT (0335 UTC)

United Launch Alliance will use the Atlas V 551 rocket tonight to launch the fourth communications satellite in the Advanced Extremely High Frequency (AEHF) series for the U.S. Air Force.

AEHF spacecraft are nuclear-hardened satellites to ensure survivable, highly-secure connectivity between U.S. national leadership and deployed military forces, routing vital communications such as real-time video, battlefield maps and targeting data in both peacetimes and during a war.

Спойлер

Atlas V rockets successfully launched the first AEHF satellite in 2010, AEHF-2 in 2012 and AEHF-3 in 2013 as the new constellation was formed in geosynchronous orbit 22,300 miles above Earth to augment and eventually replace the heritage MILSTAR satellite fleet.

AEHF-4 will be delivered into an optimized high-perigee, low-inclination geosynchronous transfer orbit following a three-and-a-half hour ascent that includes three burns by the Centaur upper stage. This orbit benefits the satellite by requiring less fuel to reach its final geosynchronous altitude.

This newest satellite will give the AEHF system full global coverage to support U.S. and allied warfighters on land, at sea and in the air. AEHF-4 ensures worldwide Extended Data Rate (XDR) protected communications, offering 10 times more communications throughput than the legacy MILSTAR constellation.

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https://www.interfax.ru/world/633665

06:41, 17 октября 2018
В YouTube заявили об устранении сбоя в работе сервиса

Москва. 17 октября. INTERFAX.RU - Видеохостинг YouTube сообщил, что неполадки в работе сервиса устранены.

"Мы вернулись! Спасибо за ваше терпение. Если у вас все еще наблюдаются проблемы, сообщите нам", - заявили в твиттере видеохостинга.

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11:44 p.m. EDT (0344 UTC)

The fuel fill sequence is beginning. This procedure releases RP-1 kerosene fuel into the RD-180 main engine in preparation for ignition.

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10/17/2018 06:45 Stephen Clark

Final preparations of the rocket's flight control system are reported complete.

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11:46 p.m. EDT (0346 UTC)

Weather is observed and forecast GO for liftoff at 12:15 a.m. EDT (0415 UTC) today, according to the countdown's final planned briefing by Air Force weather officer Jessica Williams.

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Tory Bruno‏Подлинная учетная запись @torybruno 8 мин. назад

Close to the shortest weather briefing I've heard. Clear skies and gentle breezes


8 мин. назад

Pogo suppressed charged. The Board is green. All systems looking good

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11:54 p.m. EDT (0354 UTC)

The AEHF-4 spacecraft is switching from ground-fed power to its internal batteries for launch.