Author Topic: ULA and Boeing Unveil the Atlas V Configuration for the CST-100 Starliner  (Read 25490 times)

Online Chris Bergin

https://www.nasaspaceflight.com/2016/10/atlas-v-starliner-mitigate-aerodynamic-issues/

This goes back a while per L2 notes, but finally we have the confirmation and visually:

Presser:

United Launch Alliance and the Boeing Company Unveil the Atlas V Configuration for the CST-100 Starliner Crew Capsule

 

ULA’s Atlas V will Provide Safe and Reliable Transportation for Starliner to the International Space Station

 

 

Cape Canaveral Air Force Station, Fla. (Oct. 13, 2016) – United Launch Alliance (ULA) and The Boeing Company today unveiled an updated aerodynamic configuration of the Atlas V that will launch Boeing’s CST-100 Starliner capsule for NASA after encountering unique challenges with aerodynamic stability and loads.

This new configuration incorporates an aeroskirt aft of the spacecraft, extending the Starliner Service Module cylindrical surface to improve the aerodynamic characteristics of the integrated launch configuration and bring loads margins back to acceptable flight levels.

            “Through incredible coordination and continued innovative thinking, the collective team of NASA, Boeing and United Launch Alliance completed three wind tunnel tests in six months to investigate the aerodynamic stability of various configurations and to anchor our analytical predictions. Based on that information, we updated the configuration for the Atlas V Starliner integrated vehicle stack,” said Gary Wentz, ULA vice president of Human and Commercial Services. “This configuration is unique because it combines the Atlas V launch vehicle without a payload fairing with Boeing’s Starliner capsule, resulting in different aerodynamic interactions.”

The aeroskirt is a metallic orthogrid structure designed to be jettisoned for improved performance. In the unlikely event that an emergency occurs during boost phase of flight, the aeroskirt has venting provisions to control over-pressurization if the Starliner’s abort engines are fired. Fabrication of the aeroskirt is scheduled to begin this month at ULA’s factory in Decatur, Alabama, following completion of a Production Readiness Review.

"Our testing indicates the solution we chose will sufficiently smooth the air flow around the vehicle during ascent, ensuring crew safety and mission success," said John Mulholland, vice president and program manager of Boeing's Commercial Crew Program.

The ULA team completed the aeroskirt Preliminary Design Review earlier this month. The Atlas V with Starliner has a planned uncrewed flight test in 2018 with operational missions to follow.

“We look forward to our continued partnership with Boeing and NASA to ensure mission success and safety for American astronauts flying from U.S. soil on the Atlas V Starliner,” said Wentz.

            With more than a century of combined heritage, United Launch Alliance is the nation’s most experienced and reliable launch service provider. ULA has successfully delivered more than 110 satellites to orbit that provide critical capabilities for troops in the field, aid meteorologists in tracking severe weather, enable personal device-based GPS navigation and unlock the mysteries of our solar system.

            For more information on ULA, visit the ULA website at www.ulalaunch.com, or call the ULA Launch Hotline at 1-877-ULA-4321 (852-4321). Join the conversation at www.facebook.com/ulalaunch, twitter.com/ulalaunch and instagram.com/ulalaunch.

 

Online Welsh Dragon

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Well, pretty it ain't, but if it does the trick, all is well.

Offline Rocket Science

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Hard to see any taper behind the skirt from the image... Looks a lot like a "pseudo" Apollo CM/SM now! :)
"The laws of physics are unforgiving"
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Offline rocx

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Which Atlas V configuration is this? 411? 412?
Any day with a rocket landing is a fantastic day.

Offline whitelancer64

Which Atlas V configuration is this? 411? 412?

422

2 SRBS and the Centaur upper stage will have two RL-10 engines.
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Online okan170

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At last!  Time to update the NSF CG "Future Spacecraft Library"!

Offline Newton_V

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Which Atlas V configuration is this? 411? 412?

That is SRB2 you see in the pic, so by definition it has to be a 422 configuration (ant that it's CST).
The SRBs are always attached in their specific locations.  If you only could see SRB1 on the north side, then you wouldn't know if it was a 412, or 422 (for CST), or a 411, 421, or 431 (with the 4-m PLF).

(I realize you didn't know about the SRB locations)

Offline edkyle99

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Here is a photo of a wind tunnel model.  You can see two SRMs. 

I can't understand why ULA and NASA refuse to show the base of the aeroskirt.  I doubt it is open, because hydrogen gas might accumulate, but since it extends down the side of the Centaur LH2 tank, I can't see how it could taper or close.

It seems to me an unsettling design patch, late in the game.

 - Ed Kyle
« Last Edit: 10/13/2016 03:53 PM by edkyle99 »

Offline Rocket Science

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Here is a photo of a wind tunnel model.  You can see two SRMs. 

I can't understand why ULA and NASA refuse to show the base of the aeroskirt.  I doubt it is open, because hydrogen gas might accumulate, but since it extends down the side of the Centaur LH2 tank, I can't see how it could taper or close.

It seems to me an unsettling design patch, late in the game.

 - Ed Kyle
I wonder if there is a reverse taper upwards, as a stiffener, to the Centaur...
"The laws of physics are unforgiving"
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Offline edkyle99

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Here is a photo of a wind tunnel model.  You can see two SRMs. 

I can't understand why ULA and NASA refuse to show the base of the aeroskirt.  I doubt it is open, because hydrogen gas might accumulate, but since it extends down the side of the Centaur LH2 tank, I can't see how it could taper or close.

It seems to me an unsettling design patch, late in the game.

 - Ed Kyle
I wonder if there is a reverse taper upwards, as a stiffener, to the Centaur...
Maybe.  It would have to connect to the Centaur forward skirt where the 500-series Centaur load reactor connects.  There would also have to be provisions for Centaur venting, I think.

It is going to separate after staging, kind of like a payload fairing.  Another separation step added to the design.

 - Ed Kyle
« Last Edit: 10/13/2016 04:20 PM by edkyle99 »

Offline Rocket Science

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Here is a photo of a wind tunnel model.  You can see two SRMs. 

I can't understand why ULA and NASA refuse to show the base of the aeroskirt.  I doubt it is open, because hydrogen gas might accumulate, but since it extends down the side of the Centaur LH2 tank, I can't see how it could taper or close.

It seems to me an unsettling design patch, late in the game.

 - Ed Kyle
I wonder if there is a reverse taper upwards, as a stiffener, to the Centaur...
Maybe.  It would have to connect to the Centaur forward skirt where the 500-series Centaur load reactor connects.  There would also have to be provisions for Centaur venting, I think.

It is going to separate after staging, kind of like a payload fairing.  Another separation step added to the design.

 - Ed Kyle
Yes, it is a very curious design... If I were the "chief designer" why not make it a trunk for un-pressurized cargo, but hey that's just me... ;D
« Last Edit: 10/13/2016 04:25 PM by Rocket Science »
"The laws of physics are unforgiving"
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Online woods170

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Here is a photo of a wind tunnel model.  You can see two SRMs. 

I can't understand why ULA and NASA refuse to show the base of the aeroskirt.  I doubt it is open, because hydrogen gas might accumulate, but since it extends down the side of the Centaur LH2 tank, I can't see how it could taper or close.

It seems to me an unsettling design patch, late in the game.

 - Ed Kyle
The first major delay of CST-100 (of roughly six months), as announced by Boeing last May, was mostly caused by the need to do this "design patch" and fix an overweight problem.

And now, another slip of roughly six months because Boeing screwed up the lower dome of spacecraft number 2. Let's see, in the space of less than six months the first crewed mission of CST-100 has slipped almost a year.

Ouch...

Clearly, the Boeing way of doing things is not as beatific as some had claimed here.

Offline GWH


Offline Rocket Science

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New Boeing video, complete with the new skirt:

https://twitter.com/BoeingDefense/status/786643807810879488
Thanks for posting the video. It answer's the question about what the bottom of the skirt looks like... I'll quote Mr. Spock "crude but effective"... I guess... ???
« Last Edit: 10/13/2016 08:47 PM by Rocket Science »
"The laws of physics are unforgiving"
~Rob, Physics instructor, aviator, vintage auto racer

Offline AnimatorRob

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New Boeing video, complete with the new skirt:

https://twitter.com/BoeingDefense/status/786643807810879488

Wow. Kudos to Boeing for ponying up for top-shelf animation.
« Last Edit: 10/13/2016 09:18 PM by AnimatorRob »

Offline Star One

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Here is a photo of a wind tunnel model.  You can see two SRMs. 

I can't understand why ULA and NASA refuse to show the base of the aeroskirt.  I doubt it is open, because hydrogen gas might accumulate, but since it extends down the side of the Centaur LH2 tank, I can't see how it could taper or close.

It seems to me an unsettling design patch, late in the game.

 - Ed Kyle
The first major delay of CST-100 (of roughly six months), as announced by Boeing last May, was mostly caused by the need to do this "design patch" and fix an overweight problem.

And now, another slip of roughly six months because Boeing screwed up the lower dome of spacecraft number 2. Let's see, in the space of less than six months the first crewed mission of CST-100 has slipped almost a year.

Ouch...

Clearly, the Boeing way of doing things is not as beatific as some had claimed here.

Nor is cheap points scoring welcome here.

Offline king1999

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New Boeing video, complete with the new skirt:

https://twitter.com/BoeingDefense/status/786643807810879488
Well, they call it "skirt" for a reason. The question is why didn't they do the same wind tunnel tests a few years earlier to uncover this issue and had time for a better design. This skirt is just dead weight.

Offline mfck

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New Boeing video, complete with the new skirt:

https://twitter.com/BoeingDefense/status/786643807810879488

Wow. Kudos to Boeing for ponying up for top-shelf animation.
My thoughts exactly. I doubt I've ever seen a render of such quality (judging mostly by the still frame). Moore's law, I guess... but still, somebody really wants it to be real.
« Last Edit: 10/13/2016 11:15 PM by mfck »

Offline mkent

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Ugh.  I can't wait for Vulcan.

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