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#160
by
Skyrocket
on 05 Aug, 2011 05:44
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#161
by
Geron
on 05 Aug, 2011 06:27
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I sincerely hope that in CC DEV 3 all serious comers are awarded funds through test flights. It would be amazing in 2014-2016, we had dozens of flights of new vehicles from Dreamchaser/Atlas to Dragon/Falcon9 to CST-100/Atlas.
I think you get a lot more people excited about spaceflight with that level of activity as opposed to spending another 5 billion on power points during the same period. I mean a fraction of that power point money could enable multiple commercial launch vehicles that could inspire enough multimillionaires to take orbital rides to orbital space platforms like ISS, Bigelow modules, or circumlunar travel.
An industry could be born if we focused our limited resources appropriately. Once we had this industry we could then use additional funds to leverage existing capabilitys to go BEO with the lowest cost possible.
Exciting times though! And no matter what the next five years of space flight development are going to be much more exciting than the previous 30... (IMO only:))
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#162
by
Hauerg
on 05 Aug, 2011 06:33
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This is excellent news! The most reliable launcher wins out again, glad to hear they made this choice. Cannot wait to see cst 100 fly.
Big win for US HSF in general here.
So HOW many 412 did ULA fly so far?
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#163
by
Ben the Space Brit
on 05 Aug, 2011 07:19
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This is excellent news! The most reliable launcher wins out again, glad to hear they made this choice. Cannot wait to see cst 100 fly.
Big win for US HSF in general here.
So HOW many 412 did ULA fly so far?
To my knowledge, they've flown two 411s with another in the pipe-line. So, that gives a lot of data for predicting core performance already available. One of the points of the test program will be for validating the simulation predictions on how DEC performs.
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#164
by
Skyrocket
on 05 Aug, 2011 07:26
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This is excellent news! The most reliable launcher wins out again, glad to hear they made this choice. Cannot wait to see cst 100 fly.
Big win for US HSF in general here.
So HOW many 412 did ULA fly so far?
To my knowledge, they've flown two 411s with another in the pipe-line. So, that gives a lot of data for predicting core performance already available. One of the points of the test program will be for validating the simulation predictions on how DEC performs.
Three 411 have been flown
http://space.skyrocket.de/doc_lau_det/atlas-5-411.htmDEC should also be no problem, as a very similar DEC has been flown on Atlas III
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#165
by
Jim
on 05 Aug, 2011 11:31
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ULA is not permitted to do work on spacecraft. Either Boeing, USA, or even Atrotech would do CST-100 processing.
Astrotech doesn't do hands on, they only provide facilities. Boeing will process their own spacecraft, which is SOP.
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#166
by
ugordan
on 05 Aug, 2011 11:32
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If one failed to ignite but loss of control was prevented by vectoring of the good engine, a horizontal translation would occur. I wonder whether that would create any difficulties in regard to separation from the first stage.
Centaur reaches meaningful thrust levels well beyond the CCB so there should be no issues in this regard.
Due to the reasons you state (limited gimbal angle), I'm not sure you can either thrust "forward" or through CG. Methinks you would have to pick CG and live with the cosine losses at all times.
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#167
by
Jim
on 05 Aug, 2011 11:33
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It's becoming clear to me now that Boeing envisions ULA to be for crewed commercial - at least in regard to their own capsule - what USA was to shuttle - complete launch services, including payload processing, recovery, turnaround, and maintenance. I wonder if ULA would do the same for Orion/SLS, or if it's pretty much a given that USA would inherent this contract from the shuttle program?
Huh? Boeing does not nor does ULA do such things.
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#168
by
Xplor
on 05 Aug, 2011 12:27
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I sincerely hope that in CC DEV 3 all serious comers are awarded funds through test flights. It would be amazing in 2014-2016, we had dozens of flights of new vehicles from Dreamchaser/Atlas to Dragon/Falcon9 to CST-100/Atlas.
I think you get a lot more people excited about spaceflight with that level of activity as opposed to spending another 5 billion on power points during the same period. I mean a fraction of that power point money could enable multiple commercial launch vehicles that could inspire enough multimillionaires to take orbital rides to orbital space platforms like ISS, Bigelow modules, or circumlunar travel.
An industry could be born if we focused our limited resources appropriately. Once we had this industry we could then use additional funds to leverage existing capabilitys to go BEO with the lowest cost possible.
Exciting times though! And no matter what the next five years of space flight development are going to be much more exciting than the previous 30... (IMO only:))
Very exciting idea, a true fly off like what is used successfully by the airforce for new fighters. This could happen if Congress gave NASA more funding or a fraction of SLS's $1.8B were transfered to commercial crew.
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#169
by
yg1968
on 05 Aug, 2011 13:49
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Atlas V 400 constrains the capsule mass + LAS to 20,000 lbs. Atlas V 500 can accommodate more weight, using the payload fairing for support, but I don't see how a capsule could fly inside a payload fairing.
CAnt find the source, but I believe it was previously mentioned that the Atlas V for CST-100 would be the 41X variety rather than 400
You are right, it wasn't yet official but it had been indicated previously in this presentation (of a couple of months ago) that it would be the Atlas V 412:
http://forum.nasaspaceflight.com/index.php?topic=24855.msg751698#msg751698
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#170
by
yg1968
on 05 Aug, 2011 13:53
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What, no Taurus II in the list?
Not enough capacity, solid upper stage, no flight history, lack of spacecraft processing facilities near pad.
IIRC, OSC were planning to move Taurus-II launches to KSC in the fullness of time if Prometheus had received CCDev-2 funding. It didn't so the point is moot now.
Prometheus also used the Atlas V. However, OSC had a CCDev-1 proposal with a 4 person capsule that would have used the Taurus II.
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#171
by
yg1968
on 05 Aug, 2011 13:58
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George Sowers: CST-100 will use the Atlas 5 412 configuration (one solid strap-on, dual-engine Centaur).
(Jeff Foust)
The strap-on solid bothers me for crewed flight.
- Ed Kyle
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.
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#172
by
corrodedNut
on 05 Aug, 2011 14:11
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I wonder how strange a sensation it will be for the astronauts on board when the one solid lights and the vehicle assumes its AoA at liftoff, and then goes back after SRB burnout. Like pulling the handle on your recliner, or kicking back in your rocking chair?
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#173
by
ugordan
on 05 Aug, 2011 14:18
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I think it will not feel particularly strange. I don't know if the inner ear is capable of discerning the slightly "sideways" flight during SRB burn. There's probably more sideways buffeting than that in any given launch due to high level winds.
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#174
by
xyz
on 05 Aug, 2011 15:02
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5xx has same Centaur but is inside the 5m fairing. Spacecraft load is partially carried by fairing structure.
Spacecraft load is not carried by the fairing
"Spacecraft load" includes not just axial loads, but also side-to-side loads which must be countered. The Centaur has a FLR (forward load reactor) which is there to partially distribute these side loads to the fairing so that the Centaur structure does not have to react all of the side load, as is the case for the 400 series. For the 500 series... "Spacecraft load is partially carried by fairing structure."
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#175
by
Jim
on 05 Aug, 2011 15:09
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5xx has same Centaur but is inside the 5m fairing. Spacecraft load is partially carried by fairing structure.
Spacecraft load is not carried by the fairing
"Spacecraft load" includes not just axial loads, but also side-to-side loads which must be countered. The Centaur has a FLR (forward load reactor) which is there to partially distribute these side loads to the fairing so that the Centaur structure does not have to react all of the side load, as is the case for the 400 series. For the 500 series... "Spacecraft load is partially carried by fairing structure."
Still not true. The CFLR is there to help the fairing react to aeroloads. It has nothing to do with the spacecraft. A 500 series with no spacecraft would still require the CFLR.
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#176
by
xyz
on 05 Aug, 2011 15:42
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5xx has same Centaur but is inside the 5m fairing. Spacecraft load is partially carried by fairing structure.
Spacecraft load is not carried by the fairing
"Spacecraft load" includes not just axial loads, but also side-to-side loads which must be countered. The Centaur has a FLR (forward load reactor) which is there to partially distribute these side loads to the fairing so that the Centaur structure does not have to react all of the side load, as is the case for the 400 series. For the 500 series... "Spacecraft load is partially carried by fairing structure."
Still not true. The CFLR is there to help the fairing react to aeroloads. It has nothing to do with the spacecraft. A 500 series with no spacecraft would still require the CFLR.
Yes, aeroloads, and thrust loads, and inertial loads of all sorts, tension compression and all that rot. You are responding with, what is as I understand the term, a "strawman" argument. When there is a spacecraft, which is always the case, the load that it induces (by being there and having mass) into the system is partially carried by the fairing structure. Of course the fairing loads are also carried to the Centaur through the CFLF. Saying that does not make the statement that the spacecraft loads are partially carried by the fairing (again ASSUMING a spacecraft) incorrect in any way. Thanks for reminding me why I don't comment on blogs, even this fairly high quality one. You are very knowledgable, often correcting opinion with fact, and I respect that. You should however take into account the question that was being asked. 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.
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#177
by
Danderman
on 05 Aug, 2011 15:48
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"Thickening the skin" of the Centaur won't help support > 20,000 lbs payload weight.
In a monocoque or semi-monocoque structure, the skin is very much structural. In aircraft, that skin is often only a few thousands of an inch thick.
So in a nutshell, yes it can.
Absolutely it can. All one has to do is look back at Atlas III. Some of those "balloon tank" Atlas vehicles were topped by Centaur stages weighing nearly 23 tonnes (50,700 pounds), plus payloads plus fairings, etc.. Balloon tank Atlas used pressurized stainless steel tanks just like Centaur, though likely thicker gauge.
- Ed Kyle
The 20,000 lb weight limit for Atlas V 4xx series is for the payload, not the Centaur itself.
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#178
by
Danderman
on 05 Aug, 2011 15:50
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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.
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#179
by
yg1968
on 05 Aug, 2011 16:41
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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.
Dream Chaser also use the dual centaur. It uses the Atlas V 402.