NROL-71 - Delta IV-H [D-382] - Vandenberg SLC-6 - 19.01.2019, 19:10 UTC

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NRO‏Подлинная учетная запись @NatReconOfc 1 мин.1 минуту назад


It's Launch Day for #NROL71! The rollback of the Mobile Service Tower began earlier this morning at Space Launch Complex 6 at Vandenberg AFB. Live status updates available at http://ulalaunch.com  (Photo courtesy of @ulalaunch)

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4:40 a.m. PST (7:40 a.m. EST; 1240 UTC)

This is Delta Launch Control at T-minus 5 hours, 55 minutes (L-6 hours 25 minutes) and counting. The mobile gantry at Space Launch Complex 6 has reached its park position, revealing the United Launch Alliance Delta IV Heavy rocket for the NROL-71 mission for the National Reconnaissance Office today.

The MST is a 32-story structure that weighs 13 million pounds. It is a critical part of the launch complex, proving the primary access and weather protection to the rocket during its stay on the launch pad, and its overhead crane system serves a vital role in vertical integration of payloads onto Delta IV rockets.

Rollback of the MST signals a major milestone early in launch day operations. Configuring launch pad systems and securing equipment will be completed over the next couple of hours before all personnel clear the site for fueling.

Activities remain on schedule for a liftoff at 11:05 a.m. PST (2:05 p.m. EST; 1905 UTC).

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https://spaceflightnow.com/2019/01/18/first-of-up-to-seven-ula-launches-this-year-set-for-saturday/

First of up to seven ULA launches this year set for Saturday
January 18, 2019 | Stephen Clark


File photo of the Delta 4-Heavy on Space Launch Complex-6 at Vandenberg Air Force Base, California. Credit: United Launch Alliance

The first of up to seven missions planned on United Launch Alliance's Atlas and Delta rocket fleets this year is scheduled for Saturday from California's Central Coast, when a Delta 4-Heavy is set for blastoff on a spy satellite delivery flight delayed a month to troubleshoot a hydrogen fuel leak in a booster.

Liftoff of the Delta 4-Heavy, the largest vehicle in ULA's rocket fleet, is scheduled for 11:05 a.m. PST (2:05 p.m. EST; 1905 GMT) Saturday from Space Launch Complex-6 at Vandenberg Air Force Base, a military installation around 140 miles (225 kilometers) northeast of Los Angeles.

There is a 70 percent chance of favorable weather conditions for the launch, and forecasters predict the only weather concern during the countdown will be ground winds. The weather forecast worsens Sunday, when there is just a 40 percent chance of acceptable conditions for liftoff.

Saturday's countdown is set to begin eight-and-a-half hours before liftoff with power-up of the Delta 4-Heavy's flight computer, followed by testing and checkouts of the guidance and flight control systems. The mobile gantry at the SLC-6 launch pad will be retracted to reveal the 233-foot-tall (71-meter) Delta 4-Heavy, and ULA's launch team will oversee the loading of around 465,000 gallons of cryogenic liquid hydrogen and liquid oxygen propellants into the rocket's three first stage boosters and upper stage.

After a final poll of the launch team during a built-in hold at T-minus 4 minutes, the countdown will tick down to launch, with the staggered one-by-one ignition of the Delta 4-Heavy's three Aerojet Rocketdyne RS-68A main engines set to begin at T-minus 7 seconds. After a health check of the engines, the Delta 4-Heavy will climb away from SLC-6 and head southeast over the Pacific Ocean, following a path roughly parallel to the coast of Southern California.

The payload launching Saturday is top secret, but it is owned by the National Reconnaissance Office, the U.S. government's spy satellite agency. The mission is codenamed NROL-71. Outside observers believe the payload is likely a very high-resolution imaging satellite with an Earth-facing telescope built to collect sharp pictures of strategic sites, battlefields and other targets around the world.

ULA attempted to launch the Delta 4-Heavy rocket on four occasions in December, beginning with a Dec. 7 launch attempt officials called off to investigate a glitch in the the holdfire system that would allow safety officers to abort a liftoff.

On Dec. 8, the Delta 4's automatic countdown sequencer halted the clock at T-minus 7.5 seconds, just before the rocket's three RS-68A main engines were supposed to ignite.

Engineers blamed the Dec. 8 abort on "an intermittent signal from a bad monitor (that) caused an automated hold to be triggered," wrote Tory Bruno, ULA's chief executive, on Twitter.

ULA tried again to launch the Delta 4-Heavy rocket Dec. 18, but gusty winds thwarted that launch attempt.

Managers scrubbed the next try Dec. 19 after sensors detected elevated concentrations of hydrogen around the engine section on the launcher's port-side booster after fueling the Delta 4-Heavy with cryogenic liquid propellants.

ULA's launch team conducted two tanking tests on the Delta 4-Heavy on Jan. 3 and Jan. 12 to troubleshoot the hydrogen leak, and technicians removed and replaced a valve to resolve the issue, according to Julie Arnold, a company spokesperson.

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5:14 a.m. PST (8:14 a.m. EST; 1314 UTC)

This is Delta Launch Control at T-minus 5 hours, 21 minutes (L-5 hours, 51 minutes) and counting.

The initiation of gaseous nitrogen flow to the launch vehicle has started. This changes the environmental control systems to supply conditioned nitrogen gas rather than air to the internal compartments of the Delta IV Heavy rocket and the payload fairing in preparation for the transfer of cryogenic propellants and in-flight environments.

We are tracking no issues this evening. An update from the Air Force launch weather officer is coming up in about an hour.

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5:46 a.m. PST (8:46 a.m. EST; 1346 UTC)

The launch pad crew is finishing up its hands-on work to ready Space Launch Complex 6 for today's mission, and the launch conductor has given the instruction for personnel to begin clearing the site in advance of fueling operations. Liftoff remains scheduled for just over five hours from now.

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6:00 a.m. PST (9:00 a.m. EST; 1400 UTC)

Pre-fueling tests are underway to verify the proper functions of liquid oxygen and liquid hydrogen valves on all stages of the launch vehicle.

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6:20 a.m. PST (9:20 a.m. EST; 1420 UTC) -- Countdown holding

This is Delta Launch Control at T-minus 4 hours, 15 minutes and holding. The countdown has entered the first of two planned, built-in holds that are scheduled in today's timeline. Each is 15-minute blocks of time that gives the countdown some margin to resolve issues or catch up on work could be running behind.

This particular hold serves as a margin before fueling operations begin. At the present time, however, all activities are on schedule and no significant problems are being addressed by the launch team.

The final hold occurs at T-minus 4 minutes.

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ULA‏Подлинная учетная запись @ulalaunch 6:21 - 19 янв. 2019 г.

The #DeltaIVHeavy #NROL71 countdown has entered the planned hold prior to fueling operations. Weather forecasters continue to indicate a 70 percent chance of favorable conditions for liftoff at 11:05 am PST today from Vandenberg Air Force Base in California.

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6:33 a.m. PST (9:33 a.m. EST; 1433 UTC) – GO for fueling

A readiness poll of the launch team by Launch Conductor Dillon Rice, with concurrence of ULA Launch Director Lou Mangieri has authorized cryogenic tanking operations to begin as the countdown continues this morning. The Delta IV Heavy rocket will be loaded with approximately 465,000 gallons of liquid oxygen and liquid hydrogen over the next couple of hours.

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6:35 a.m. PST (9:35 a.m. EST; 1435 UTC) -- Countdown resumes

This is Delta Launch Control at T-minus 4 hours, 15 minutes and counting. The next phase of today's launch countdown has been initiated on schedule as we continue to target 11:05 a.m. PST (2:05 p.m. EST; 1905 UTC) for liftoff of the United Launch Alliance Delta IV Heavy rocket on NROL-71.

Preparatory steps for fueling are being kicked off, including liquid hydrogen storage tank pressurization and charging the helium bottles on the three common booster cores and second stage.

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7:16 a.m. PST (10:16 a.m. EST; 1516 UTC)

The fueling specialist in the launch control room confirms that liquid hydrogen is flowing into the Delta IV Heavy rocket at the Space Launch Complex 6 pad.

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:!:  
https://spaceflightnow.com/2019/01/19/live-coverage-delta-4-heavy-readied-for-launch-from-vandenberg-air-force-base/#coverage

A note about our coverage:

For decades the news media has been provided with audio feeds to enable coverage of the countdown and ascents of U.S. launch vehicles. We were very disappointed to learn on Friday that United Launch Alliance has decided to change this practice for its launches.

A ULA spokeswoman said the company had performed an evaluation of its provision of audio lines and had decided to discontinue them.

For this current mission the company will permit audio feeds to be released two hours prior to liftoff. This will prevent independent coverage of the crucial fueling phase of the countdown.

After this launch no uninterrupted, clean audio from the launch control center will be released to the news media in realtime. Unless alternatives are offered, the only source of information on the countdown will be from ULA's corporate communications department via its website and social media accounts.

Spaceflight Now hopes United Launch Alliance will reverse this decision but unless they do we are no longer able offer the accurate, timely and impartial coverage of ULA launches that you have come to expect.

This decision by United Launch Alliance does not affect our coverage of other launch companies.

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7:55 a.m. PST (10:55 a.m. EST; 1555 UTC)

The common booster core liquid oxygen tanking operation is switching from "slow-fill" to "fast-fill" mode. The LOX is chilled to minus-298 degrees F.

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Из переписки

Rome Strach‏ @romn8tr 17:20 - 18 янв. 2019 г

Can you discuss hardware issue?

Tory Bruno‏Подлинная учетная запись @torybruno 7:18 - 19 янв. 2019 г.

В ответ @romn8tr

Valve. Very small hydrogen leak, but only at cryo temps. Removed and replaced. Verified. Probably would have been fine, but we don't take those kind of risks.

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8:17 a.m. PST (11:17 a.m. EST; 1617 UTC)

This is Delta Launch Control. We have finished the "fast-fill" loading mode for the three common booster core liquid hydrogen tanks, and the post-fueling checks and valve tests are underway before topping commences.

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Tory Bruno‏Подлинная учетная запись @torybruno 14 мин. назад

Tanking. No issues. Board is green. #NROL71

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01/19/2019 20:09 Stephen Clark

At this point in the countdown, the Delta 4-Heavy's Common Booster Core first stages have been filled with super-cold liquid hydrogen and liquid oxygen propellants. Filling of the second stage continues with its supply of cryogenic fluids.

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9:14 a.m. PST (12:14 p.m. EST; 1714 UTC)

The Delta Cryogenic Second Stage has been loaded with its liquid hydrogen fuel supply. The propellant, along with liquid oxygen that continues to be filled, will be consumed by the stage's RL10B-2 engine.

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9:30 a.m. PST (12:30 p.m. EST; 1730 UTC)

The standard post-fueling inspections of the rocket's outer thermal insulation is underway using launch pad cameras.

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Gene J. Mikulka‏ @genejm29 25 мин.25 минут назад


Via .@ulalaunch - A "Family Portrait " of the United Launch Alliance #DeltaIV. A DeltaIV Heavy is set to cary a .@NatReconOfc payload #NROL71 to orbit from Vandenberg AFB Today at 11:05 AM PST (7:05 PM GMT)