Author Topic: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09  (Read 135890 times)

Offline otisbow

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #220 on: 01/17/2009 09:49 PM »
Us OLD GUYs with a BIG DISH in the back yard can watch the launch on satellite  G-3.

Offline Nick L.

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #221 on: 01/17/2009 09:55 PM »
Telemetry RF link tests underway.
"Now you may leave here for four days in space, but when you return it's the same old place..."

Offline William Graham

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #222 on: 01/17/2009 10:05 PM »
Now less than 90 minutes away from launch

Offline Nick L.

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #223 on: 01/17/2009 10:12 PM »
FTS receivers being tested.
"Now you may leave here for four days in space, but when you return it's the same old place..."

Offline Rocket Nut

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #224 on: 01/17/2009 10:14 PM »
I am heading out now...hope there is somewhere to park...should be spectacular, weather is great.

Offline HIPAR

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #225 on: 01/17/2009 10:27 PM »
Do those three core boosters remain strapped together until staging?

---  CHAS

Offline generic_handle_42

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #226 on: 01/17/2009 10:30 PM »
Do those three core boosters remain strapped together until staging?

---  CHAS

The two boosters on the sides will separate before the centre one burns out.
« Last Edit: 01/17/2009 10:30 PM by generic_handle_42 »
-Nick-

Offline edkyle99

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #227 on: 01/17/2009 10:30 PM »
Do those three core boosters remain strapped together until staging?

---  CHAS

No.  On Delta IV Heavy flights, all three CBCs ignite on the pad. The core CBC engine throttles down to 60% about one minute after liftoff. The twin strap-on booster CBC units burn at full thrust until the 3.85 minute mark. At that point, the strap-on units throttle down to 60% and the core throttles up to 100%. The strap-on units burn out and separate after 4.3 minutes. The core CBC shuts down about one minute later.

 - Ed Kyle

Offline DaveS

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #228 on: 01/17/2009 10:30 PM »
Do those three core boosters remain strapped together until staging?

---  CHAS
No. The two side CBCs will be jettisoned first after which the center CBC burns for a while longer after which it too is shut down and jettisoned after which the upperstage ignites.
"For Sardines, space is no problem!"
-1996 Astronaut class slogan

"We're rolling in the wrong direction but for the right reasons"
-USA engineer about the rollback of Discovery prior to the STS-114 Return To Flight mission

Offline Nick L.

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #229 on: 01/17/2009 10:30 PM »
Do those three core boosters remain strapped together until staging?

---  CHAS

No. The outer two are run at full power for their entire burn duration and so run out of fuel earlier. The center one throttles back to 58% a few seconds after liftoff. When the outer two run out, the center CBC (which still has fuel left) goes to full power and the outer two separate. The center CBC runs for a little bit longer until 1-2 sep.

If you go back and watch the video of the last D-IVH launch, you can actually see the center engine throttle down if you look closely. The flame gets a little smaller compared to the outers.
« Last Edit: 01/17/2009 10:33 PM by Nick L. »
"Now you may leave here for four days in space, but when you return it's the same old place..."

Offline ugordan

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #230 on: 01/17/2009 10:31 PM »
Do those three core boosters remain strapped together until staging?

They (the strap-ons) are jettisoned earlier. The core CBC runs on lower throttle for much of the flight so saves more propellant for a longer burntime instead of expending part of its kick on boosting the other two boosters along.
« Last Edit: 01/17/2009 10:33 PM by ugordan »

Offline Nick L.

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #231 on: 01/17/2009 10:34 PM »
Steering tests are beginning soon.
"Now you may leave here for four days in space, but when you return it's the same old place..."

Offline HIPAR

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #232 on: 01/17/2009 10:35 PM »
Thanks to everyone for helping me understand how it works.

---  CHAS

Offline Nick L.

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #233 on: 01/17/2009 10:38 PM »
Second stage slews complete. First stage is next.
"Now you may leave here for four days in space, but when you return it's the same old place..."

Offline Matthew From Florida

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #234 on: 01/17/2009 10:42 PM »
Hi, don't have time to read all the posts now... is everything still go for tonight, and what time is launch?

Offline Nick L.

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #235 on: 01/17/2009 10:43 PM »
7:33 PM ET. Everything is still go at this point. *knock on wood*
"Now you may leave here for four days in space, but when you return it's the same old place..."

Offline Nick L.

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #236 on: 01/17/2009 10:44 PM »
CBC slew tests complete.
"Now you may leave here for four days in space, but when you return it's the same old place..."

Offline Matthew From Florida

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #237 on: 01/17/2009 10:46 PM »
Thanks, I'll be watching from the Oviedo area.

Offline generic_handle_42

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #238 on: 01/17/2009 10:46 PM »
7:33 PM ET. Everything is still go at this point. *knock on wood*

And for those interested, the webcast will start at 7:07pm EST.
-Nick-

Offline Nick L.

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Re: LIVE: Delta IV Heavy: NRO L-26 - Jan 17, 09
« Reply #239 on: 01/17/2009 10:51 PM »
Less than 45 minutes to go.
"Now you may leave here for four days in space, but when you return it's the same old place..."

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