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#60 by Star One on 21 May, 2014 06:33
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Lobo, I agree, but this is the Delta IV for Commercial Crew thread.
I know...just explaining why it's an unlikley scenario, IMO. So it's on topic when discussing if Delta IV carrying commercial crew is a possibility.
Physically? Yes. Practically? No. and expained why I felt that way.
It was physically capable of taking Orion to the ISS for CxP, but we see how that worked out. ;-)
It's all very well talking about developing a new engine but that it would seem would take at least four years plus a fair chunk of change. Adapting Delta IV is probably going to be at least cheaper.
http://m.aviationweek.com/space/replacing-russian-made-atlas-antares-engines-would-take-four-years -
#61 by baldusi on 21 May, 2014 13:41
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After all, Common avionic and Common Upper stage is part of current ULA plan. And most of the human rating effort and integration work could be reused.
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#62 by PahTo on 21 May, 2014 14:17
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I read more closely the 2009 ULA discussion of upgrade paths and see the common upper stage is notionally a common Centaur. ULA points out that while some high energy orbits will be negatively impacted by such a change for Delta IV (the Medium I presume) due to the lower prop load, the LEO performance will be improved with the 2-engine Centaur. -
#63 by muomega0 on 21 May, 2014 14:44
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It's all very well talking about developing a new engine but that it would seem would take at least four years plus a fair chunk of change. Adapting Delta IV is probably going to be at least cheaper.
http://m.aviationweek.com/space/replacing-russian-made-atlas-antares-engines-would-take-four-yearsQuote from: avweek"I can say that the U.S. is capable of developing and fielding products similar to the capability of those that we purchase today," she said. "The country hasn’t committed to developing those products over the past several decades. We’re prepared to do that." Despite the uncertainty over the RD-180, Van Kleek said Aerojet Rocketdyne is getting ready to build an expendable version of the RS-25D Space Shuttle Main Engine for the heavy-lift Space Launch System (SLS) that NASA is developing for deep-space human exploration.
Contrast this with the 2006 AF/DOD Report on Future Propulsion NeedsQuoteThe RD-180 was developed and qualified in 42 months at a much lower cost than past U.S. booster engine developments because of the strong flight-proven RD-170 heritage.
Finding 4-2. The current family of U.S. EELV boosters does not need to be replaced for the next 15 to 20 years, nor are there plans to do so. Nevertheless several candidate designs were started under NASA’s Space Launch Initiative (SLI) program in 2001.
Recommendation 4-2. DoD should begin work relatively slowly, investing about $5 million per year in the committee’s judgment on technology development for an advanced-cycle booster engine that could provide the basis for a new far-term access-to-space vehicle. -
#64 by baldusi on 21 May, 2014 16:07
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I believe they are referring to the DIVUS 5m stage. The 4m has practically the same same load and much worse pmf.
I read more closely the 2009 ULA discussion of upgrade paths and see the common upper stage is notionally a common Centaur. ULA points out that while some high energy orbits will be negatively impacted by such a change for Delta IV (the Medium I presume) due to the lower prop load, the LEO performance will be improved with the 2-engine Centaur. -
#65 by Lobo on 21 May, 2014 20:03
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Lobo, I agree, but this is the Delta IV for Commercial Crew thread.
I know...just explaining why it's an unlikley scenario, IMO. So it's on topic when discussing if Delta IV carrying commercial crew is a possibility.
Physically? Yes. Practically? No. and expained why I felt that way.
It was physically capable of taking Orion to the ISS for CxP, but we see how that worked out. ;-)
It's all very well talking about developing a new engine but that it would seem would take at least four years plus a fair chunk of change. Adapting Delta IV is probably going to be at least cheaper.
http://m.aviationweek.com/space/replacing-russian-made-atlas-antares-engines-would-take-four-years
Since commerical crew has nothing to do with USAF and DoD, if Atlas V were to loose Russian engines, and no new US made replacement developed because it would take 4 years, then do you think adapting D4 is more likely than F9?
If SpaceX wins, it'll be F9 for sure.
If SNC wins, and Atlas is unavailable, do you think they'll pay for a modified D4? Or go with F9 which would already be basically man-rated, and launching from KSC?
If Boeing wins, maybe D4 would be in play. It wa their LV afterall and they wanted CST-100 launching on it originally, but that switched to Atlas. And now Boeing has mentioned the possibility of swithcing to F9 after maybe two initial Atlas V launches (I remember reading some where). So now if AV is no longer available, what's the most likely LV for CST-100? Or F9?
That's why I said, IMHO, D4 is pretty unlikely to ever be used for commercial crew. That will either be Atlas or Falcon.
Not to ruin everyone's fun about imagining D4 doing it, but I'm just not seeing it.
As always, I could be wrong. ;-)
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#66 by PahTo on 21 May, 2014 20:21
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I believe they are referring to the DIVUS 5m stage. The 4m has practically the same same load and much worse pmf.
I read more closely the 2009 ULA discussion of upgrade paths and see the common upper stage is notionally a common Centaur. ULA points out that while some high energy orbits will be negatively impacted by such a change for Delta IV (the Medium I presume) due to the lower prop load, the LEO performance will be improved with the 2-engine Centaur.
To make sure I understand, does this mean the (notional) path forward would be to fly the common Centaur upper stage on the Delta IV Heavy? That seems like a huge performance hit considering the prop load and vehicle in question.
I've been pondering all of this further, and ULA's decision to go with Centaur as the common upper stage results from the impact of using a 4m or 5m DCSS on Atlas V performance, and the fact that for pretty much any profile, at least one SRM would be needed for Atlas. Because of this, Centaur (and the performance hit on certain/fewer D-IV profiles) seemed the better choice. Now with the uncertainty of the RD-180, and considering ACES involves a 5m common upper stage, I wonder if that might change? -
#67 by baldusi on 22 May, 2014 00:05
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What they meant was to move the Delta IV 4meters to Centaur.
I believe they are referring to the DIVUS 5m stage. The 4m has practically the same same load and much worse pmf.
I read more closely the 2009 ULA discussion of upgrade paths and see the common upper stage is notionally a common Centaur. ULA points out that while some high energy orbits will be negatively impacted by such a change for Delta IV (the Medium I presume) due to the lower prop load, the LEO performance will be improved with the 2-engine Centaur.
To make sure I understand, does this mean the (notional) path forward would be to fly the common Centaur upper stage on the Delta IV Heavy? That seems like a huge performance hit considering the prop load and vehicle in question.
I've been pondering all of this further, and ULA's decision to go with Centaur as the common upper stage results from the impact of using a 4m or 5m DCSS on Atlas V performance, and the fact that for pretty much any profile, at least one SRM would be needed for Atlas. Because of this, Centaur (and the performance hit on certain/fewer D-IV profiles) seemed the better choice. Now with the uncertainty of the RD-180, and considering ACES involves a 5m common upper stage, I wonder if that might change? -
#68 by Rocket Science on 22 May, 2014 00:27
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Or Lobo, the U.S. will still want two different launch vehicles from lessons learned for insurance...Lobo, I agree, but this is the Delta IV for Commercial Crew thread.
I know...just explaining why it's an unlikley scenario, IMO. So it's on topic when discussing if Delta IV carrying commercial crew is a possibility.
Physically? Yes. Practically? No. and expained why I felt that way.
It was physically capable of taking Orion to the ISS for CxP, but we see how that worked out. ;-)
It's all very well talking about developing a new engine but that it would seem would take at least four years plus a fair chunk of change. Adapting Delta IV is probably going to be at least cheaper.
http://m.aviationweek.com/space/replacing-russian-made-atlas-antares-engines-would-take-four-years
Since commerical crew has nothing to do with USAF and DoD, if Atlas V were to loose Russian engines, and no new US made replacement developed because it would take 4 years, then do you think adapting D4 is more likely than F9?
If SpaceX wins, it'll be F9 for sure.
If SNC wins, and Atlas is unavailable, do you think they'll pay for a modified D4? Or go with F9 which would already be basically man-rated, and launching from KSC?
If Boeing wins, maybe D4 would be in play. It wa their LV afterall and they wanted CST-100 launching on it originally, but that switched to Atlas. And now Boeing has mentioned the possibility of swithcing to F9 after maybe two initial Atlas V launches (I remember reading some where). So now if AV is no longer available, what's the most likely LV for CST-100? Or F9?
That's why I said, IMHO, D4 is pretty unlikely to ever be used for commercial crew. That will either be Atlas or Falcon.
Not to ruin everyone's fun about imagining D4 doing it, but I'm just not seeing it.
As always, I could be wrong. ;-) -
#69 by Lobo on 22 May, 2014 16:38
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Or Lobo, the U.S. will still want two different launch vehicles from lessons learned for insurance...
I think the current plan is to down select to just one spacecraft which will fly on just one LV, although at least DC and CST-100 could fly on other LV's. It wouldn't be a swap out though in case there's a problem with the primary LV. Moving DC or CST-100 from Atlas to Falcon or Delta if there were a problem with Atlas would take time I would think. Interfaces, crew access at the LV pad, etc. I woudl think a swap would be longer than 6 months, which is the time from that the next crew service would need to be done in.
So I don't think a true "backup" LV for commercial crew is in the plan. I think SLS/Orion is supposed to be that backup. Athough, given it's planned low production rate, not sure how likely that would be unless NASA keeps an Orion capsule, upper stage and SLS core/boosters stored somewhere for a contingency mission. Otherwise I doubt they could have an SLS/Orion ready to launch in the required time frame to offer a true backup.
In actual application, any problem with the primary space craft or LV would be backed up with Soyuz. NASA would just have to pay through the nose at that point if they need the Russians to provide more crew service after commercial crew takes over. But I'm sure they would for a price, and that's probably the best "backup" plan. -
#70 by PahTo on 23 May, 2014 16:17
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You know, I had intended for my 1,000th post to be something really impressive and thoughtful and all that, and then boom, I missed that my 1,000th just came and went. So allow me, with my 1,001st post to volunteer my very being to be ballast on the first manned flight of DCSS (Dream Chaser Space Ship) on the DCSS (Delta-Centaur second stage) atop the first human-rated Delta IV M 4+2.
(my first shuttle launch in person came the same year NSF really took off, STS-116. Can't thank enough Chris, NSF and all of you for increasing my knowledge, excitement and involvement with everything space!) -
#71 by Jim on 23 May, 2014 18:06
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DCSS (Delta-Centaur second stage) atop the first human-rated Delta IV M 4+2.
Delta Cryogenic Second State. There is no relationship to the Centaur. -
#72 by PahTo on 23 May, 2014 18:23
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DCSS (Delta-Centaur second stage) atop the first human-rated Delta IV M 4+2.
Delta Cryogenic Second State. There is no relationship to the Centaur.
I know that DCSS = Delta Cryo Second Stage. Per the ULA document from Dec 2009 stating a goal of a common upper stage using Centaur (and eventually ACES) I thought I'd just cut to the chase and mash the names now. -
#73 by Rocket Science on 23 May, 2014 19:45
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I think if we put all our eggs in one basket it would be silly return on investment by not getting two U.S. spacecraft on two different U.S. launch vehicles whatever they are. Then again, we have been silly before...Or Lobo, the U.S. will still want two different launch vehicles from lessons learned for insurance...
I think the current plan is to down select to just one spacecraft which will fly on just one LV, although at least DC and CST-100 could fly on other LV's. It wouldn't be a swap out though in case there's a problem with the primary LV. Moving DC or CST-100 from Atlas to Falcon or Delta if there were a problem with Atlas would take time I would think. Interfaces, crew access at the LV pad, etc. I woudl think a swap would be longer than 6 months, which is the time from that the next crew service would need to be done in.
So I don't think a true "backup" LV for commercial crew is in the plan. I think SLS/Orion is supposed to be that backup. Athough, given it's planned low production rate, not sure how likely that would be unless NASA keeps an Orion capsule, upper stage and SLS core/boosters stored somewhere for a contingency mission. Otherwise I doubt they could have an SLS/Orion ready to launch in the required time frame to offer a true backup.
In actual application, any problem with the primary space craft or LV would be backed up with Soyuz. NASA would just have to pay through the nose at that point if they need the Russians to provide more crew service after commercial crew takes over. But I'm sure they would for a price, and that's probably the best "backup" plan. -
#74 by Star One on 23 May, 2014 21:14
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Or Lobo, the U.S. will still want two different launch vehicles from lessons learned for insurance...
I think the current plan is to down select to just one spacecraft which will fly on just one LV, although at least DC and CST-100 could fly on other LV's. It wouldn't be a swap out though in case there's a problem with the primary LV. Moving DC or CST-100 from Atlas to Falcon or Delta if there were a problem with Atlas would take time I would think. Interfaces, crew access at the LV pad, etc. I woudl think a swap would be longer than 6 months, which is the time from that the next crew service would need to be done in.
So I don't think a true "backup" LV for commercial crew is in the plan. I think SLS/Orion is supposed to be that backup. Athough, given it's planned low production rate, not sure how likely that would be unless NASA keeps an Orion capsule, upper stage and SLS core/boosters stored somewhere for a contingency mission. Otherwise I doubt they could have an SLS/Orion ready to launch in the required time frame to offer a true backup.
In actual application, any problem with the primary space craft or LV would be backed up with Soyuz. NASA would just have to pay through the nose at that point if they need the Russians to provide more crew service after commercial crew takes over. But I'm sure they would for a price, and that's probably the best "backup" plan.
One would hope they would have more sense than to get into such a situation. -
#75 by A_M_Swallow on 27 May, 2014 17:00
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After a test flight on Atlas V all three spacecraft will end up launching on Falcon 9s. Unless the Blue Origin launch vehicle flies within 4-5 years then the Delta IV will be man rated.
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#76 by bad_astra on 27 May, 2014 19:16
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Russia is not going to prohibit sales of RD180 for ISS launches. There's no reason to abandon Atlas V for this. Calmer heads will prevail, eventually.
