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#180 by joek on 05 Aug, 2011 17:42
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Dream Chaser also use the dual centaur. It uses the Atlas V 402.If you read the selection statement for CCDev-2, one of the reason that Dream Chaser was chosen above OSC's Prometheus was that Dream Chaser used the Atlas V 402 whereas the Prometheus used a larger version of the Atlas V. I wonder if the choice of the Atlas 412 will be taken into account for CCDev-3.
I am sure that the additional cost to NASA of developing 2 engine Centaur for Atlas V will be considered, along with the cost of modifying Atlas V 4xx to accommodate more than 20,000 lbs payload mass. I am not sure at all if NASA wants to bear those costs.
As apparently does everyoneelse (except SpaceX)who is considering or has selected Atlas V for commercial crew. Per ULA:QuoteAtlas Dual Engine Centaur ... has been baselined by all CCT Companies that we are currently working with.
Which would imply that if Atlas V is in the future of commercial crew, so is DEC.
edit: clarify "everyone" -
#181 by Space Pete on 05 Aug, 2011 17:50
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#182 by clongton on 05 Aug, 2011 18:40
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If you read the selection statement for CCDev-2, one of the reason that Dream Chaser was chosen above OSC's Prometheus was that Dream Chaser used the Atlas V 402 whereas the Prometheus used a larger version of the Atlas V. I wonder if the choice of the Atlas 412 will be taken into account for CCDev-3.
I am sure that the additional cost to NASA of developing 2 engine Centaur for Atlas V will be considered, along with the cost of modifying Atlas V 4xx to accommodate more than 20,000 lbs payload mass. I am not sure at all if NASA wants to bear those costs.
Multi-engine Centaurs have already flown and the current design already has a designed evolution to multi-engine. The design work is already done. Costs to NASA would be reduced to implimentation and qualification.QuoteModular design enables multiple engine configurations from one to six RL-10s
http://en.wikipedia.org/wiki/Centaur_(rocket_stage) -
#183 by yg1968 on 06 Aug, 2011 02:15
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Dream Chaser also use the dual centaur. It uses the Atlas V 402.If you read the selection statement for CCDev-2, one of the reason that Dream Chaser was chosen above OSC's Prometheus was that Dream Chaser used the Atlas V 402 whereas the Prometheus used a larger version of the Atlas V. I wonder if the choice of the Atlas 412 will be taken into account for CCDev-3.
I am sure that the additional cost to NASA of developing 2 engine Centaur for Atlas V will be considered, along with the cost of modifying Atlas V 4xx to accommodate more than 20,000 lbs payload mass. I am not sure at all if NASA wants to bear those costs.
As apparently does everyoneelse (except SpaceX)who is considering or has selected Atlas V for commercial crew. Per ULA:QuoteAtlas Dual Engine Centaur ... has been baselined by all CCT Companies that we are currently working with.
Which would imply that if Atlas V is in the future of commercial crew, so is DEC.
edit: clarify "everyone"
For Blue Origin, there was a presentation that said that it was either the Atlas V 401 or 402. -
#184 by Jim on 06 Aug, 2011 17:39
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I was trying to give a brief explanation to someone trying to understand whether the Centaur used for a 500 series was 5m in diameter, and was not aware that the Centaur is actually encapsulated in the fairing along with the spacecraft, and thought it would be nice to include a caveat that this arrangement reguires a structural accomodation. You chose to be pedantic, that is to say, you missed the point. I would be happy to respond to any further questions via PM.
No, I was clarifying it for the same person. A layman when seeing a statement such as "Spacecraft load is carried by the fairing" would assume that spacecraft is connected to the fairing, which it is not. -
#185 by xyz on 06 Aug, 2011 19:03
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I'll bite, and not my tongue. You have misquoted my original post, again. My use of the adverb "partially" modifies the verb "carries" which was intended to indicate that the spacecraft load was not entirely reacted by the Centaur when employed in the 500 series configuration. if you were interested in clarifying for the layman you should have said that they are not physically connected, but instead you added to the ambiguity by saying flatly and incorrectly that no spacecraft load is carried by the fairing.
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#186 by phred on 10 Aug, 2011 17:36
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A manned flight in 2015? That's awesome. I'm wondering a few things:
1) The RD-180 is still manufactured in Russia, right? How could this affect things?
2) Is there a safer option to the SRB, or would any option be more complicated than building a new launcher?
3) Since Atlas V is so extensible, is there any suggestion of eventually increasing CST-100's capability, say with a larger service module? -
#187 by zaitcev on 10 Aug, 2011 18:03
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1) The RD-180 is still manufactured in Russia, right? How could this affect things?
As far as I know, which is admittedly not very far, domestic production is possible but needs far, far greater launch rate to occur (numbers like 20 launches per year were thrown about). So in the short term a careful attention is given to stockpiling years worth of RD-180. In the long term, it may be possible to re-engine with whatever Aeroject threatens to produce. They keep making noises about liquid boosters for SLS (if you recall Zenit 1st stage was used as a side booster for Energiya in a similar scheme). That may possibly be an option, in case. But most likely the Russian production of RD-180 is going to continue, with RD-180V baselined for Rus-M. -
#188 by Lurker Steve on 10 Aug, 2011 18:39
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I was trying to give a brief explanation to someone trying to understand whether the Centaur used for a 500 series was 5m in diameter, and was not aware that the Centaur is actually encapsulated in the fairing along with the spacecraft, and thought it would be nice to include a caveat that this arrangement reguires a structural accomodation. You chose to be pedantic, that is to say, you missed the point. I would be happy to respond to any further questions via PM.
No, I was clarifying it for the same person. A layman when seeing a statement such as "Spacecraft load is carried by the fairing" would assume that spacecraft is connected to the fairing, which it is not.
OK, lay person commenting again.
Both Atlas V models use the same CCB, which is 3.81m in diameter. The Centaur second stage mounts on top of the CCB. The second stage is also common between both the 400 and 500 models. The spacecraft mounts to the top of the second stage. The only difference between the 2 families, is the size of the fairing, correct ?
But in the case of commerical crew vehicles, there is no fairing because the spacecraft is exposed. I suppose that ULA or Boeing will have to develop some sort of adapter for mounting the CST-100 to the top of the stack. Perhaps this adapter helps distribute/translate the loads similar to the 500 series fairing.
Of course, Dream Chaser and Blue Origin may have to develop a similar adapter to fly their space craft on the Altas, since they will be different physical shapes.
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#189 by erioladastra on 11 Aug, 2011 01:40
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1) The RD-180 is still manufactured in Russia, right? How could this affect things?
As far as I know, which is admittedly not very far, domestic production is possible but needs far, far greater launch rate to occur (numbers like 20 launches per year were thrown about). So in the short term a careful attention is given to stockpiling years worth of RD-180. In the long term, it may be possible to re-engine with whatever Aeroject threatens to produce. They keep making noises about liquid boosters for SLS (if you recall Zenit 1st stage was used as a side booster for Energiya in a similar scheme). That may possibly be an option, in case. But most likely the Russian production of RD-180 is going to continue, with RD-180V baselined for Rus-M.
I *believe* that someone here has the plans for the RD180. The military refused to accept using Russian hardware until there was enough stockpiled and someone had the ability to ramp up and start making them if something happened. -
#190 by docmordrid on 11 Aug, 2011 02:17
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Let's presume AJ26-500 or Merlin 2 becomes real at the right price. Could we then tell Russia to stuff it? Would we?
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#191 by mborgia on 11 Aug, 2011 03:07
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I have asked this before elsewhere, but why is Delta IV not being given any consideration for roles as commercial spacecraft launcher?
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#192 by zaitcev on 11 Aug, 2011 03:34
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I *believe* that someone here has the plans for the RD180.
See http://forum.nasaspaceflight.com/index.php?topic=26303.180
-- Pete -
#193 by Downix on 11 Aug, 2011 04:05
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I have asked this before elsewhere, but why is Delta IV not being given any consideration for roles as commercial spacecraft launcher?
The cost to man rate is over a billion dollars due to the lack of redundancy systems and detection systems. For a commercial vendor to consider, they would have to foot that bill, but then all could enjoy the benefits of their up front cost. -
#194 by alexw on 11 Aug, 2011 04:21
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I have asked this before elsewhere, but why is Delta IV not being given any consideration for roles as commercial spacecraft launcher?
Essentially because it's more expensive than Atlas V to outfit and rate it for humans. RS-68 requires at least some reworking, where RD-180 does not. DIV Medium (4,0)'s 9.3mT performance is a little bit low for many of the crew vehicles, although M+(4,2) at 12.5mT is comparable to AV402.
Possibly the biggest issue is the pad: DIV stacks at the pad, so LC-37B would be unavailable for government use (including the Heavy missions that presumably take longer to build up) while the Com. Crew was prepping. This may not be a showstopper, but it means there's call for a second pad (LC-37A) if Delta were to see much use for this, and that's pricey.
Atlas spends only ~24 hours at the pad, and more easily parallelizes in two ways: with a second MLP (relatively cheap) you can build two vehicles at once, and presumably launch them in either order, and with a second assembly building (by retrofitting the SMARF as VIF2) you could completely segregate the commercial and government users. (I don't know if VIF(1) could stack two vehicles within it with two MLP, but it could certainly handle three Atlas boosters simultaneously.)
You certainly *could* use Delta, and in a world where Delta was flying often it would be easier to spread out the greater costs and justify the effort. At rock-bottom minimal flight rate, there's little incentive to do anything with Delta other than try to lower its costs (e.g. by leveraging DOD's need for RD-68A), rather than enhance its features.
It would be interesting to hear more from Boeing/LockMart/ULA folks on their impressions, but no doubt they feel compelled to speak guardedly.
-Alex
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#195 by Jim on 11 Aug, 2011 12:54
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Atlas spends only ~24 hours at the pad, and more easily parallelizes in two ways: with a second MLP (relatively cheap) you can build two vehicles at once, and presumably launch them in either order, and with a second assembly building (by retrofitting the SMARF as VIF2) you could completely segregate the commercial and government users. (I don't know if VIF(1) could stack two vehicles within it with two MLP, but it could certainly handle three Atlas boosters simultaneously.)
VIF can only handle one MLP -
#196 by mike robel on 11 Aug, 2011 17:08
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I have asked this before elsewhere, but why is Delta IV not being given any consideration for roles as commercial spacecraft launcher?
Possibly the biggest issue is the pad: DIV stacks at the pad, so LC-37B would be unavailable for government use (including the Heavy missions that presumably take longer to build up) while the Com. Crew was prepping. This may not be a showstopper, but it means there's call for a second pad (LC-37A) if Delta were to see much use for this, and that's pricey.
If I am not mistaken, Delta IV stacks in its Horizontal Integration Facitliy (or whatever it may be called) and only integrates the payload on the pad.
Also, there is room for multiple launch vehicles in the HIF.
I am sure Jim will blow me out of the room if I am wrong here.
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#197 by erioladastra on 11 Aug, 2011 17:18
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I think you misheard or misread something. The first manned flight isn't planned to dock to ISS.
Ah, I see - so just a rendezvous, and no docking?
I'd still take that.
Sorry for the delay - but this is interesting. This is the first time that Boeing has suggested that. It has not been discussed with NASA. Now in the end, like SpaceX, I suspect they will push to combine the first near rednezvous and demo but it will be an interesting discussion. -
#198 by zaitcev on 11 Aug, 2011 19:32
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VIF can only handle one MLP
I saw some discussion about building a VIF extension from the other side, so the second MLP would backtrack a bit and switch. It's basically a question of money. -
#199 by Jim on 11 Aug, 2011 19:58
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VIF can only handle one MLP
I saw some discussion about building a VIF extension from the other side, so the second MLP would backtrack a bit and switch. It's basically a question of money.
Not feasible without shutting down ongoing operations and causes other issues like the location of PVan and GVan. All studies were of new buildings.
