Author Topic: Boeing's CST-100 capsule updates & discussion THREAD 2  (Read 521109 times)

Offline Star One

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #80 on: 01/27/2014 03:11 pm »
Either way if there is the addition of two SRBs is there any knock on as flight safety checks are concerned? I would think the less additional items on the Atlas V manned flights the better.

Offline BrightLight

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #81 on: 01/27/2014 03:33 pm »
So why does this need the 522 configuration yet DC can use the no doubt cheaper 402 configuration?

Do we know that CST-100 will use the 522? How do we know it's not the 422?
No, I don't know if the LV is a 522 - in fact, I have no clear definitions other than Atlas V what configuration the  CST-100 will use?

Offline Zed_Noir

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #82 on: 01/27/2014 03:36 pm »
So why does this need the 522 configuration yet DC can use the no doubt cheaper 402 configuration?

Don't be to sure about the DC using the 402 configuration. Until we get liftoff mass of the entire DC stack. Also ULA might be unwilling to developed both the 4X2 and 5X2 versions of the AV.

Offline BrightLight

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #83 on: 01/27/2014 03:40 pm »
The web is full of pictures of the CSt-100 with and without SRB's on the Atlas V LV.
Is there a publication/article etc defining the LV?
the best I have is the FISO report in February 2013:
 http://spirit.as.utexas.edu/~fiso/telecon/Reiley_2-6-13/Reiley_2-6-13.pptx

the pictures show two SRB's - but this is hardly definitive.
Just for reference, I found from another web site that the difference between a 402 and a 522  configurations was about $5 million.
« Last Edit: 01/27/2014 04:33 pm by BrightLight »

Offline arachnitect

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #84 on: 01/27/2014 06:04 pm »
Quote from: http://spaceflightnow.com/news/n1306/02cst100/
The capsule will launch on a version of the Atlas 5 known as the 422 model - with a two-engine Centaur and two solid rocket boosters - in the launcher's catalog of configurations tailored to the size and destination of the payload for each launch, according to a Boeing spokesperson.

I wouldn't have found that if I hadn't known what to look for, so thanks to Oli for spotting the second SRB. You win internet points Oli.

Don't know why people think this is a 500 series: the Centaur is clearly not encapsulated.

Also don't know why people think this hurts CST. They already needed at least 1 SRB, so adding another doesn't change much (a few $). If DC has mass growth they'll probably end up doing the same thing.

Offline Lars_J

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #85 on: 01/27/2014 06:16 pm »
Exactly. The image does NOT show a 500 series Atlas V. It is a non-encapsulated Centaur stage. I'm not sure what it will be called, since it has no fairing - But it is certainly closer to a 422 than a 522 model.

Offline Elmar Moelzer

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #86 on: 01/27/2014 06:29 pm »
Also don't know why people think this hurts CST. They already needed at least 1 SRB, so adding another doesn't change much (a few $). If DC has mass growth they'll probably end up doing the same thing.
DC is still supposed to use the 402, from all that is currently known. I was not aware that the CST was originally supposed to use the 412. I thought it was going to be the 402 just like the DC.

Offline BrightLight

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #87 on: 01/27/2014 06:35 pm »
Also don't know why people think this hurts CST. They already needed at least 1 SRB, so adding another doesn't change much (a few $). If DC has mass growth they'll probably end up doing the same thing.
DC is still supposed to use the 402, from all that is currently known. I was not aware that the CST was originally supposed to use the 412. I thought it was going to be the 402 just like the DC.
Right - my question still stands, does the addition of the SRB's (only about $5 million, not that much considering) change the reliability of the Atlas V.

Online Robotbeat

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #88 on: 01/27/2014 06:44 pm »
Also don't know why people think this hurts CST. They already needed at least 1 SRB, so adding another doesn't change much (a few $). If DC has mass growth they'll probably end up doing the same thing.
DC is still supposed to use the 402, from all that is currently known. I was not aware that the CST was originally supposed to use the 412. I thought it was going to be the 402 just like the DC.
Right - my question still stands, does the addition of the SRB's (only about $5 million, not that much considering) change the reliability of the Atlas V.
Well, it doesn't /improve/ the reliability.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline newpylong

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #89 on: 01/27/2014 07:01 pm »
I've seen illustrations of everything from 402 to 422, so who knows what it will end up being. Too much speculation. It definitely is not a 5xx though.

Offline Lurker Steve

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #90 on: 01/27/2014 07:17 pm »
Also don't know why people think this hurts CST. They already needed at least 1 SRB, so adding another doesn't change much (a few $). If DC has mass growth they'll probably end up doing the same thing.
DC is still supposed to use the 402, from all that is currently known. I was not aware that the CST was originally supposed to use the 412. I thought it was going to be the 402 just like the DC.
Right - my question still stands, does the addition of the SRB's (only about $5 million, not that much considering) change the reliability of the Atlas V.
Well, it doesn't /improve/ the reliability.

It might improve the reliability of the overall system. since there is spare thrust in the first stage.

As long as they already had 1 solid, I don't see adding a second solid making it any less safe.

The 40x is definitely the most common / flown Atlas configuration, but from Ed Kyle's launch log it appears that the 4/521 configuration has flown 4 times while the 411 configuration has only flown twice. Of course, there are plenty of 3 and 5 SRB launches as well. The only "partial" failure Ed has ever logged with Atlas is when the Centaur shut down a few seconds early, causing the sat to need to put itself into the proper orbit.


Offline Lars_J

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #91 on: 01/27/2014 07:23 pm »
It might improve the reliability of the overall system. since there is spare thrust in the first stage.

As long as they already had 1 solid, I don't see adding a second solid making it any less safe.

Statistics. That's why. You are adding a possible failure point.

How does that spare thrust help you? There is no scenario where a first stage engine out (or booster out) is recoverable.

Atlas V doesn't launch with more SRBs than needed.

Offline arachnitect

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #92 on: 01/27/2014 07:33 pm »
It might improve the reliability of the overall system. since there is spare thrust in the first stage.

As long as they already had 1 solid, I don't see adding a second solid making it any less safe.

Statistics. That's why. You are adding a possible failure point.

How does that spare thrust help you? There is no scenario where a first stage engine out (or booster out) is recoverable.

Atlas V doesn't launch with more SRBs than needed.

Yes it adds risk to the booster, but the difference is quite manageable. Sure an SRM failure doomed a Delta II once, but how many SRMs flew without incident on Delta II alone? It's a non issue.

It improves reliability by increasing your mass margin on the spacecraft (can use heavier components, add redundancy, no need to mess around with composites). Also CST doesn't have to use its LAS to get into orbit like DC does.
« Last Edit: 01/27/2014 07:40 pm by arachnitect »

Online Robotbeat

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #93 on: 01/27/2014 08:05 pm »
...adding another SRB doesn't improve reliability compared to a similar vehicle launched without one. How is this really in question?

I agree it probably has negligible effect on reliability, though. Atlas V is one of the most reliable launch vehicles on record.
« Last Edit: 01/27/2014 08:07 pm by Robotbeat »
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Online edkyle99

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #94 on: 01/27/2014 08:22 pm »
...adding another SRB doesn't improve reliability compared to a similar vehicle launched without one. How is this really in question?

I agree it probably has negligible effect on reliability, though. Atlas V is one of the most reliable launch vehicles on record.
I wonder which has larger, albeit small incremental, reduction effect on reliability - one extra solid motor or one extra RL10?  My bet would be RL10.

 - Ed Kyle
« Last Edit: 01/27/2014 08:22 pm by edkyle99 »

Online Robotbeat

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #95 on: 01/27/2014 08:26 pm »
...adding another SRB doesn't improve reliability compared to a similar vehicle launched without one. How is this really in question?

I agree it probably has negligible effect on reliability, though. Atlas V is one of the most reliable launch vehicles on record.
I wonder which has larger, albeit small incremental, reduction effect on reliability - one extra solid motor or one extra RL10?  My bet would be RL10.

 - Ed Kyle
...I think I agree. Especially since the RL-10 is started on-orbit (not during first-stage hold-down where it can be aborted intact in case of early problem being detected).
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline joek

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #96 on: 01/27/2014 08:30 pm »
The wind tunnel images for both CST-100 and Dream Chaser (images attached) show an Atlas 4xx; no SRB shown but may be on other side.  Edit: presumably that's a 4x2 as both CST-100 and DC have stated DEC is required.
« Last Edit: 01/27/2014 08:32 pm by joek »

Online edkyle99

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #97 on: 01/27/2014 08:50 pm »
The wind tunnel images for both CST-100 and Dream Chaser (images attached) show an Atlas 4xx; no SRB shown but may be on other side.  Edit: presumably that's a 4x2 as both CST-100 and DC have stated DEC is required.
Keep in mind that these wind tunnel tests likely run through a series of vehicle configurations to mimic the range of flight conditions.  These images might just be showing the set up to test post solid separation conditions, for example.

 - Ed Kyle

Offline Jim

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #98 on: 01/27/2014 11:31 pm »

It improves reliability by increasing your mass margin on the spacecraft (can use heavier components, add redundancy, no need to mess around with composites). Also CST doesn't have to use its LAS to get into orbit like DC does.

You are mixing apples and oranges. 
1.  The launch vehicle reliability is lowered
2.  And you can't say it increases spacecraft reliability.  It doesn't matter if the spacecraft doesn't make into orbit. 
« Last Edit: 01/27/2014 11:40 pm by Jim »

Offline arachnitect

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Re: Boeing's CST-100 capsule updates & discussion THREAD 2
« Reply #99 on: 01/28/2014 12:56 am »

It improves reliability by increasing your mass margin on the spacecraft (can use heavier components, add redundancy, no need to mess around with composites). Also CST doesn't have to use its LAS to get into orbit like DC does.

You are mixing apples and oranges. 
1.  The launch vehicle reliability is lowered
2.  And you can't say it increases spacecraft reliability.  It doesn't matter if the spacecraft doesn't make into orbit. 

Fair enough.

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