Author Topic: LIVE: Delta IV - GPS 2F-1 - May 27, 2010  (Read 85853 times)

Offline Chris Bergin

LIVE: Delta IV - GPS 2F-1 - May 27, 2010
« on: 03/23/2010 03:23 AM »
Starting a thread for this launch as Atlantis now holds priority on the range:

http://www.nasaspaceflight.com/2010/03/sts-132-atlantis-deal-ula-may-14-range-ownership/

Launch preview/overview, by William Graham:

http://www.nasaspaceflight.com/2010/05/live-delta-iv-launch-gps-iif-sv-1/ 

Offline HIPAR

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #1 on: 03/26/2010 02:36 PM »
Hopefully the Shuttle will leave on schedule allowing the Air Force to finally commence its GPS Block IIF modernization program.

Last spring,  General Accounting Office projected the GPS effectiveness will soon suffer degradation as old equipment fails.  That prediction has yet to materialize. Our GPS system operators have done fantastic work maintaining satellites well past their design life.  Remarkably, satellites dating way back to early nineties are still operating.

There must also be some element of 'luck' evolved as many of the Block IIA satellites have, for several years,  been just a component away from navigation mission failure.

Experiencing numerous developmental difficulties, GPS IIF-1 is many years delinquent.  We really need to get it checked out in space to clear the remaining eleven satellites for delivery. Hopefully, those will sustain the constellation until Block III satellites become available.

Currently thirty satellites are usually available.

---  CHAS 



« Last Edit: 03/26/2010 02:43 PM by HIPAR »

Offline HIPAR

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #2 on: 04/30/2010 12:03 AM »
There's a nice writeup about GPS IIF -1 spacecraft processing and its launch at Spaceflight Now:

http://spaceflightnow.com/delta/d349/100429cleanroom/

Liftoff of the GPS 2F-1 spacecraft from pad 37B is targeted for May 20 during a launch window extending from 11:29 to 11:48 p.m. EDT.

---  CHAS

Offline robertross

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #3 on: 04/30/2010 12:10 AM »
Note to a mod: we need a thread title change, and the calender needs updating!
It's too bad I leave the day before launch...would have been nice to see it go up.
Remembering those who made the ultimate sacrifice for our rights & freedoms, and for those injured, visible or otherwise, in that fight.

Offline the_roche_lobe

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #4 on: 04/30/2010 06:47 AM »
Interesting that it requires the solids. Are there any more 'core only' Delta IV launches on the manifest?

P

Offline DGH

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #5 on: 04/30/2010 10:58 AM »
Interesting that it requires the solids. Are there any more 'core only' Delta IV launches on the manifest?

P

The weird thing is a base Delta IV can put 3859 lbs excluding PAF to GPS orbit.
The satellite is according to the article 3,400 lbs.
That is 113.5% of the required mass.


A Delta IV 4,2  can put 6,157 lbs excluding PAF to GPS orbit.
That is 181% of the required mass.

I do not know why the Air Force is going with the 4,2 it does not appear to be needed.

Maybe they are planning for the future or launching something else small with it.

Offline kevin-rf

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #6 on: 04/30/2010 12:30 PM »

Margin? Enough to completely remove the US from the GPS plane?

Just a guess...
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Offline edkyle99

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #7 on: 04/30/2010 02:14 PM »

I do not know why the Air Force is going with the 4,2 it does not appear to be needed.

Maybe they are planning for the future or launching something else small with it.

Piggyback payloads are always a possibility, but removing the upper stage from the GPS orbit seems to be a part of the answer. 

 - Ed Kyle

Offline HIPAR

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #8 on: 04/30/2010 10:37 PM »
Will that excess propellant be sufficient to actually deorbit the second stage?

---  CHAS

Offline mainengine

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #9 on: 05/02/2010 11:45 AM »
What inclination will this rocket fly ?

Offline Nate_Trost

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #10 on: 05/02/2010 07:45 PM »
Wasn't ULA eliminating the no-solids Delta 4 configuration to cut down on the number of CBC variations?

Offline bobthemonkey

Re: Delta IV - GPS 2F-1 - May 21
« Reply #11 on: 05/02/2010 10:04 PM »
Sorta.

The plan is/was to use eliminate the 4,0 core, and replace it with the 4,2 core. this only works however with the performance boost given by going with the RS-68A engine.

Offline Chris Bergin

Re: Delta IV - GPS 2F-1 - May 21
« Reply #12 on: 05/03/2010 02:13 PM »
Mission booklet:

Offline WHAP

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #13 on: 05/03/2010 02:40 PM »
Sorta.

The plan is/was to use eliminate the 4,0 core, and replace it with the 4,2 core. this only works however with the performance boost given by going with the RS-68A engine.

I think the plan is to use an equivalent to a 5,4 core, or at least one that could handle any size PLF and up to 4 solids with minimal add-ons, if any, to the structure.  As you stated, RS-68A is necessary.
« Last Edit: 05/03/2010 02:41 PM by WHAP »
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Offline edkyle99

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #14 on: 05/03/2010 05:26 PM »
Will that excess propellant be sufficient to actually deorbit the second stage?

---  CHAS

The mission booklet posted today tells us that the answer to your question is "no".  It says that after spacecraft separation the stage will perform a propellant blowdown while aimed 30 degrees out of plane to move the stage "into [a] disposed orbit of approximately 11,000 x 11,600 nautical miles (nmi) and off operational plane inclination".

 - Ed Kyle

Offline Chris Bergin

Re: Delta IV - GPS 2F-1 - May 21
« Reply #15 on: 05/18/2010 01:08 PM »
All on track - according to ULA - with the launch is set for Thursday, May 20, with a launch window of 11:29-11:48 p.m. EDT.  If the launch slips, the next attempt is May 21 with a launch window of 11:25-11:43 p.m. EDT.
 

Launch Day:

Overall Probability of Weather Constraint Violation:    20% 

Primary Concern:  Anvil Cloud Rule

 

24-Hour Delay:

Overall Probability of Weather Constraint Violation:    30% 

Primary Concern:  Anvil Cloud Rule

 

Surface and upper level high pressure ridge will slowly build back in from

the west as the upper level trough responsible for yesterday's widespread

thunderstorm activity moves east of the peninsula.  Deep layered moisture

will decrease as the high pressure ridge builds in from the west. Afternoon

showers and thunderstorms will still be possible however the amount of

coverage will decrease over the next couple of days.  On Thursday deep

layered moisture will continue to decrease but remain sufficient for a

slight chance of isolated afternoon thunderstorm development.  Isolated

thunderstorms developing along the east coast sea breeze will be possible

during the launch countdown, mainly over inland areas.  There is the

potential for lingering anvil clouds associated with any thunderstorms that

do develop to be in the area during the launch window.  The Anvil Cloud Rule

will be the primary concern for both launch day, and the next day in the

event of a 24 hour launch delay.


Offline sdsds

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #16 on: 05/19/2010 02:41 AM »
According to ulalaunch.com the launch attempt has been rescheduled for May 21, due to trouble with a Fixed Umbilical Tower swing arm.
-- sdsds --

Offline Chris Bergin

Re: Delta IV - GPS 2F-1 - May 21
« Reply #17 on: 05/19/2010 10:32 AM »
Delta IV GPS IIF-SV1 Mission Rescheduled for May 21

            Cape Canaveral AFS , Fla. (May 18, 2010) - The launch attempt of the United Launch Alliance Delta IV with the Air Force’s Global Positioning System IIF-SV1satellite (GPS IIF-SV1) has been rescheduled for May 21. During normal processing for launch, mission managers determined a piece of ground support equipment used to control one of the swing arms on the Fixed Umbilical Tower was not operating correctly and needed replacing.

 Replacing this GSE component will add one day to launch processing. The Delta IV rocket and GPS IIF-SV1 satellite are safe and secure at this time. The launch is rescheduled for Friday, May 21, with a launch window of 11:25 – 11:43 p.m. EDT.

Offline bbliss

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #18 on: 05/19/2010 07:19 PM »
Mission booklet:

Thanks for that link, Chris!  I found it informative.

One thing that I didn't know about (caveat: I'm a launch newbie) before I read that document was the concept of PCS, second stage Probability of Command Shutdown >= 99.7% (page 12).

For the benefit of anybody else who might wonder what that means, to save them from having to dig, the Delta people's explanation is that "0% PCS means spacecraft orbit insertion at second-stage cutoff always occurs due to a propellant depletion shutdown (PDS) and is never commanded by guidance."

So, apparently, given the various things that fluctuate from nominal on launch day (like weather), and assuming successful launch vehicle operation, you have a 99.7% chance of not running out of "gas" before you've reached your target destination.

I'd be curious if anyone knows more about, on chart 5, which signals are sent to the re-radiating antennae outside the fairing, and which are just leaking through the 14" diameter RF window?  I'm assuming the re-rad antennae are for S-band telemetry of the vehicle?

Offline Kim Keller

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Re: Delta IV - GPS 2F-1 - May 21
« Reply #19 on: 05/19/2010 07:41 PM »
I'd be curious if anyone knows more about, on chart 5, which signals are sent to the re-radiating antennae outside the fairing, and which are just leaking through the 14" diameter RF window?  I'm assuming the re-rad antennae are for S-band telemetry of the vehicle?

Used during ground checkout/test, they allow the customer to verify the operation of the spacecraft RF systems by sending commands and receiving telemetry.

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