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

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Tory Bruno‏Подлинная учетная запись @torybruno 33 мин. назад

Mighty Atlas is resting at the pad. RP tanked and thinking about space. Pgo at 70%.
#AEHF4

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Прогноз погоды L-0 на 17.10.2018

AV-073 AEHF-4 L-0 Forecast

80% GO

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Tory Bruno‏Подлинная учетная запись @torybruno 2 ч. назад

Interesting trajectory tonight. All our orbits are customized. This is a GTO, but we will coast for several hours out to apogee and then do a major lift of the perigee. This will leave the spacecraft with only a small amout of remaining energy to add in order to circularize.

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Tory Bruno‏Подлинная учетная запись @torybruno 5 мин. назад

#AEHF4

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Русскоязычная трансляция:

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https://spaceflightnow.com/2018/10/15/av-073-rollout/

Photos: Atlas 5 rocket transferred to launch pad in Florida
October 15, 2018 | Stephen Clark

EDITOR'S NOTE: Upd ated with rollout photos.


The Atlas 5 rocket set for launch with the U.S. Air Force's fourth AEHF communications satellite. Credit: United Launch Alliance

A day-and-a-half before its liftoff with a U.S. Air Force communications satellite, a United Launch Alliance Atlas 5 rocket rolled out to its launch pad at Cape Canaveral on Monday morning.

Set to fly in its most powerful configuration with five solid rocket boosters, the Atlas 5 arrived in the starting blocks at Cape Canaveral's Complex 41 launch pad after a 1,800-foot (550-meter) journey from ULA's nearby Vertical Integration Facility.

The Air Force's fourth Advanced Extremely High Frequency, or AEHF, communications satellite is fastened on top of the Atlas 5 rocket, inside a 17.7-foot-wide (5.4-meter) nose fairing. Built by Lockheed Martin with a Northrop Grumman-made nuclear-hardened secure communications payload, the AEHF 4 satellite will enable video, voice and data links between government leaders and military commanders.

The AEHF 4 spacecraft joins three previous AEHF satellites launched on Atlas 5 rockets in 2010, 2012 and 2013.

The 197-foot-tall (60-meter) Atlas 5 rocket is se t for liftoff in a two-hour window opening at 12:15 a.m. EDT (0415 GMT) Wednesday.

More photos of the Atlas 5's rollout are posted below.


Credit: United Launch Alliance

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Credit: United Launch Alliance


Credit: United Launch Alliance


Credit: United Launch Alliance


Credit: United Launch Alliance


Credit: United Launch Alliance


Credit: United Launch Alliance


Credit: United Launch Alliance


Credit: United Launch Alliance


Credit: United Launch Alliance


Credit: United Launch Alliance


Credit: United Launch Alliance


Credit: United Launch Alliance

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https://spaceflightnow.com/2018/10/16/atlas-5-av-073-mission-status-center/

Live coverage: Atlas 5 rocket poised for launch from Cape Canaveral
October 16, 2018 | Stephen Clark

10/16/2018 21:46 Stephen Clark

A United Launch Atlas 5 rocket is set to launch the U.S. Air Force's fourth Advanced Extremely High Frequency communications satellite from Cape Canaveral. This timeline shows the major mission events planned over a three-and-a-half-hour flight to an optimized geostationary transfer orbit.

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https://spaceflightnow.com/2018/10/16/launch-timeline-for-atlas-5s-aehf-4-mission/

Launch timeline for Atlas 5's AEHF 4 mission
October 16, 2018 | Stephen Clark

A United Launch Atlas 5 rocket is set to launch the U.S. Air Force's fourth Advanced Extremely High Frequency communications satellite from Cape Canaveral. This timeline shows the major mission events planned over a three-and-a-half-hour flight to an optimized geostationary transfer orbit.

The 197-foot-tall (60-meter) rocket, propelled by an RD-180 main engine and five solid rocket boosters, is set for liftoff during a two-hour launch window Wednesday that opens at 12:15 a.m. EDT (0415 GMT).

The AEHF 4 mission will be the 79th flight of an Atlas 5 rocket, and the fifth Atlas 5 launch of 2018.

Built by Lockheed Martin, the AEHF 4 satellite joins three previous satellites in the AEHF constellation launched by Atlas 5 rockets in 2010, 2012 and 2013. With four AEHF satellites in orbit, the Air Force's new generation of secure, nuclear-hardened voice, video and data relay spacecraft will provide global coverage.

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An overview of the Atlas 5/AEHF 4 launch sequence and a ground track map illustrating the rocket's path after liftoff are posted .



Credit: United Launch Alliance

T+0:00:01.1: Liftoff


After igniting its RD-180 main engine at T-minus 2.7 seconds, the Atlas 5 rocket fires its five solid rocket boosters and rises away from Complex 41 at Cape Canaveral Air Force Station, Florida, with approximately 2.6 million pounds of thrust.

T+0:00:34.6: Mach 1


The Atlas 5 rocket exceeds the speed of sound, flying east from Cape Canaveral Air Force Station.

T+0:00:48.4: Max-Q


The Atlas 5 rocket passes through the region of maximum dynamic pressure during ascent through the lower atmosphere.

T+0:01:50.7: Jettison SRBs


Having burned out of propellant approximately 20 seconds earlier, the five spent Aerojet Rocketdyne-built solid rocket boosters are jettisoned once dynamic pressure conditions are satisfied.

T+0:03:28.6: Payload Fairing Jettison


The Atlas 5 rocket's payload fairing, made in Switzerland by Ruag Space, is jettisoned in a clamshell-like fashion once external heating levels drop below predetermined limits after climbing through the dense lower atmosphere. The Forward Load Reactor deck that connected the payload fairing's structure to the Centaur upper stage is released five seconds after the shroud's jettison.

T+0:04:27.4: Main Engine Cutoff


The RD-180 main engine completes its firing after consuming its kerosene and liquid oxygen fuel supply in the Atlas first stage.

T+0:04:33.4: Stage Separation


The Common Core Booster first stage of the Atlas 5 rocket separates from the Centaur upper stage. Over the next few seconds, the Centaur engine liquid hydrogen and liquid oxygen systems are readied for ignition.

T+0:04:43.4: Centaur Ignition 1


The Centaur RL10C-1 engine ignites for the first of three upper stage firings. This burn will inject the Centaur stage and the AEHF 4 satellite into an initial parking orbit.

T+0:11:51.3: Centaur Cutoff 1


The Centaur engine shuts down after arriving in a planned low-Earth parking orbit. The vehicle enters a 10-minute coast period before arriving at the required location in space for the second burn.

T+0:22:25.2:  Centaur Ignition 2


Producing 22,900 pounds of thrust, the Centaur re-ignites to accelerate the payload into a highly elliptical transfer orbit from the parking altitude achieved earlier in the launch sequence. This burn lasts nearly six minutes.

T+0:28:19.1: Centaur Cutoff 2


The second Centaur firing places the AEHF 4 satellite into an elliptical transfer orbit stretching more than 20,000 miles above Earth, beginning a three-hour coast period for the mission's final orbital adjustment maneuver.

T+3:28:20.4: Centaur Ignition 3


After a three-hour coast, the Centaur's RL10 engine reignites for a roughly one-minute, 40-second firing to place the AEHF 4 satellite in the proper orbit for spacecraft separation.

T+3:30:00.1: Centaur Cutoff 3


The powered phase of flight is concluded as the Centaur reaches the planned elliptical geostationary transfer orbit with an apogee, or high point, of 21,933 miles (35,299 kilometers), a perigee, or low point, of 5,539 miles (8,914 kilometers), and an inclination of 12.8 degrees.

T+3:32:49.1: AEHF 4 Separation


The AEHF 4 spacecraft deploys from the Centaur upper stage.

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5:15 p.m. EDT (2115 UTC)

From the Atlas Spaceflight Operations Center at Cape Canaveral Air Force Station in Florida, this is Atlas Launch Control at T-minus 6 hours, 20 minutes and holding.

We are just seven hours away from liftoff of the United Launch Alliance Atlas V rocket with the U.S. Air Force's Advanced Extremely High Frequency-4 spacecraft, a protected communications satellite to operate in geosynchronous orbit.

Activities are on schedule for liftoff from Space Launch Complex 41 at 12:15 a.m. EDT (0415 UTC). The launch window extends to 2:15 a.m. EDT (0615 UTC), a duration of exactly two hours.

We will be starting the countdown at 5:25 p.m.

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5:25 p.m. EDT (2125 UTC) -- Countdown begins

This is Atlas Launch Control at T-minus 6 hours, 20 minutes (L-6 hours, 50 minutes) and counting.

Countdown clocks are ticking for our liftoff just after midnight tonight. There are two pre-planned, built-in holds, each lasting 15 minutes, scheduled in the count. One pause is reserved prior to fueling at T-minus 2 hours, the other occurs prior to the terminal count at T-minus 4 minutes.

The Atlas V rocket, designated AV-073, will launch AEHF-4 into a high-perigee, low-inclination elliptical geosynchronous transfer orbit. This orbit benefits the satellite by requiring less fuel to reach its final circular geosynchronous altitude 22,300 miles above the Earth, as explained in a tweet by ULA CEO Tory Bruno earlier today.

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"Interesting trajectory tonight. All our orbits are customized. This is a GTO, but we will coast for several hours out to apogee and then do a major lift of the perigee. This will leave the spacecraft with only a small amount of remaining energy to add in order to circularize," Bruno said.

It will take three hours and 33 minutes to perform this Atlas V mission, from liftoff until deployment of the AEHF-4 spacecraft, and the Centaur upper stage will perform three burns to haul the heavy payload to the optimized orbit.

Our rocket variant being flown tonight is the Atlas V 551 configuration that is distinguished by the five-meter-wide composite payload fairing, five solid rocket boosters that are side-mounted to the first stage and a single RL10C-1 engine on the Centaur upper stage. It stands 197 feet tall.

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5:40 p.m. EDT (2140 UTC)

This is Atlas Launch Control and T-minus 6 hours, 5 minutes (L-6 hours, 35 minutes) and counting.

The application of power to the Atlas and Centaur stages is underway at the start of today's countdown procedures. The stages are being powered up to begin launch day testing and final preparations for fueling operations.

Over the next few hours, final preps for the liquid oxygen and liquid hydrogen systems will be performed, along with a test of the rocket's guidance system and the first stage propulsion and hydraulic preps, internal battery checks and testing of the GPS metric tracking system used to follow the rocket as it flies downrange, plus a test of the S-band telemetry relay system.

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Chris B - NSF‏ @NASASpaceflight 7 мин. назад

Personally speaking, it's always great to see the Union Jack on a rocket fairing.

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6:06 p.m. EDT (2206 UTC)

Power up of the Atlas-Centaur rocket for today's AEHF-4 launch has been accomplished. Guidance system testing is the next major milestone in the countdown as we continue tracking on schedule for liftoff at 12:15 a.m. EDT (0415 UTC). At T-minus 5 hours 39 minutes (L-6 hours, 9 minutes) and counting, this is Atlas Launch Control.

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6:37 p.m. EDT (2237 UTC)

The guidance system test is beginning.

6:42 p.m. EDT (2242 UTC)

We are working no issues in the countdown. Liftoff remains scheduled for 12:15 a.m. EDT (0415 UTC).

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ULA‏Подлинная учетная запись @ulalaunch 3 мин. назад

Weather is 90% go for launch.
#AtlasV #AEHF4Road2Launch

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7:00 p.m. EDT (2300 UTC)

A photo of the Atlas V rocket taken a short time ago. Credit: United Launch Alliance.

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John Kraus‏ @johnkrausphotos 4 ч. назад

Which one of these birds is going to space tonight!? @ulalaunch is poised to launch this Atlas V rocket, carrying #AEHF4 for the U.S. Air Force, at 12:15am EDT Wednesday morning.

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Ken Kremer‏ @ken_kremer 2 ч. назад

Beautiful afternoon views #AtlasV rocket and @RuagSpace payload fairing launching #AEHF4 milsatcom just after midnight tonight @ulalaunch @torybruno for @usairforce #SpaceCommand 1215 AM Oct 17 @CapeCanaveral #CCAFS #pad41 #ULA #USAF . Cred: @ken_kremer http://www.facebook.com/spaceupclose321/ ...

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Ken Kremer‏ @ken_kremer 37 мин. назад

"#ULA Ready for Nightime Liftoff of USAF #AEHF4 National Security Relay Comsat Oct 17 on Mighty Atlas V: Pad Photos, Watch Live"-@ulalaunch @torybruno #AtlasV @usairforce #SpaceCommand #pad41 @RuagSpace #USAF. Story/pics @ken_kremer http://www.facebook.com/spaceupclose321/ ...
https://kenkremer.blogspot.com/2018/10/ula-ready-for-nightime-liftoff-of-usaf.html ...

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7:12 p.m. EDT (2312 UTC)

The flight control operational test is getting underway. This test will validate the control functions on the Atlas first stage main engine and the Centaur upper stage's engine by confirming that valves cycle properly and that the engine steering systems perform as commanded.