Would it have enough thrust for the M+ versions?Yes, and also with a Heavy if the two boosters are RS-68. (the payload jumps to almost 45mT)
I don't like playing with Frankenrockets, but a structural feasibility study of a dual-SSME CBC would not be a horrible idea. It could solve some performance problems. If SLS can get the flight rate up, it might even be more economical than RS-68.
I don't like playing with Frankenrockets, but a structural feasibility study of a dual-SSME CBC would not be a horrible idea. It could solve some performance problems. If SLS can get the flight rate up, it might even be more economical than RS-68.
Considering the recent price hike on engines, any idea how much the SSME/ RS-25e will cost these days?
Am I the only one that think it is a shame to throw away all these SSMEs on every flight? How is that affordable?
Considering the recent price hike on engines, any idea how much the SSME/ RS-25e will cost these days?
Am I the only one that think it is a shame to throw away all these SSMEs on every flight? How is that affordable?
Considering the recent price hike on engines, any idea how much the SSME/ RS-25e will cost these days?
Am I the only one that think it is a shame to throw away all these SSMEs on every flight? How is that affordable?
The price hike was due to the fixed costs of PWR that had been borne by the SSME contract being spread over the other engine programs after the FY11 budget seemed to indicate the coming demise of the SSME contract. I'm extrapolating a bit that the unit cost of SSMEs would not be any worse than it had been.
Considering the recent price hike on engines, any idea how much the SSME/ RS-25e will cost these days?
Am I the only one that think it is a shame to throw away all these SSMEs on every flight? How is that affordable?
The price hike was due to the fixed costs of PWR that had been borne by the SSME contract being spread over the other engine programs after the FY11 budget seemed to indicate the coming demise of the SSME contract. I'm extrapolating a bit that the unit cost of SSMEs would not be any worse than it had been.
One could seriously consider the RD-0120 for the expendables such as the replacement for RS-68 and for the SLS considering the price advantage. The RD-0120 performance is very comparable to the SSME but at a significant lower price.
400k / 663k is 40% less not 25%
Considering the recent price hike on engines, any idea how much the SSME/ RS-25e will cost these days?
Am I the only one that think it is a shame to throw away all these SSMEs on every flight? How is that affordable?
The price hike was due to the fixed costs of PWR that had been borne by the SSME contract being spread over the other engine programs after the FY11 budget seemed to indicate the coming demise of the SSME contract. I'm extrapolating a bit that the unit cost of SSMEs would not be any worse than it had been.
One could seriously consider the RD-0120 for the expendables such as the replacement for RS-68 and for the SLS considering the price advantage. The RD-0120 performance is very comparable to the SSME but at a significant lower price.Not really, not in the order quantities being talked about. Plus, the RD-0120 is not produced anymore. NASA has, however, studied it extensively with an eye to adapting it to the SSME, This combined design is referred to as the RS-25e. Best of both worlds, higher performance, lower cost. SSME has better thrust, equal isp. With the proposed changes, restarting the RD-0120 production would cost more, take longer, and give you an engine with less performance.
Something I noticed as well. The SSME is not *that* much less thrust than an RS-68, only 25% less. The RD-0120, however, is 45% less than the RS-68. With the SSME's better isp, it still wins. If we do follow NASA's plan to reduce the cost to produce by adapting technologies from other engines, there is no compelling argument against the SSME in my opinion.
Considering the recent price hike on engines, any idea how much the SSME/ RS-25e will cost these days?
Am I the only one that think it is a shame to throw away all these SSMEs on every flight? How is that affordable?
The price hike was due to the fixed costs of PWR that had been borne by the SSME contract being spread over the other engine programs after the FY11 budget seemed to indicate the coming demise of the SSME contract. I'm extrapolating a bit that the unit cost of SSMEs would not be any worse than it had been.
One could seriously consider the RD-0120 for the expendables such as the replacement for RS-68 and for the SLS considering the price advantage. The RD-0120 performance is very comparable to the SSME but at a significant lower price.Not really, not in the order quantities being talked about. Plus, the RD-0120 is not produced anymore. NASA has, however, studied it extensively with an eye to adapting it to the SSME, This combined design is referred to as the RS-25e. Best of both worlds, higher performance, lower cost. SSME has better thrust, equal isp. With the proposed changes, restarting the RD-0120 production would cost more, take longer, and give you an engine with less performance.
Something I noticed as well. The SSME is not *that* much less thrust than an RS-68, only 25% less. The RD-0120, however, is 45% less than the RS-68. With the SSME's better isp, it still wins. If we do follow NASA's plan to reduce the cost to produce by adapting technologies from other engines, there is no compelling argument against the SSME in my opinion.
RS-0120 has a better Isp than the SSME.
SSME sea level thrust@ 109% power is at 419K lbf, so that's only 63% of RS-68A, the RD-0120 sea level thrust is at 341K, at 51% of RS-68A.
But that makes the RD-0120 a better fit as a replacement of RS-68s.
Two RD-01020 is just about identical as one RS-68A thrust, therefore minimum structural modification on the CBC other than the obvious (2 engine feed & gimbals). At a significantly higher Isp, itwill make the Delta-IV a higher performance vehicle with minimum mods.
SSME, on the other hand, will require way too much throttling than currently capable.
As far as on currently in production, well; 1) the market place is a tremendous motivator, and 2) SSME is currently not in production either. Just try to find the toolings for them.
As for the "NASA studies", there's a huge difference between "study" and "done it".
Considering the recent price hike on engines, any idea how much the SSME/ RS-25e will cost these days?
Am I the only one that think it is a shame to throw away all these SSMEs on every flight? How is that affordable?
The price hike was due to the fixed costs of PWR that had been borne by the SSME contract being spread over the other engine programs after the FY11 budget seemed to indicate the coming demise of the SSME contract. I'm extrapolating a bit that the unit cost of SSMEs would not be any worse than it had been.
One could seriously consider the RD-0120 for the expendables such as the replacement for RS-68 and for the SLS considering the price advantage. The RD-0120 performance is very comparable to the SSME but at a significant lower price.Not really, not in the order quantities being talked about. Plus, the RD-0120 is not produced anymore. NASA has, however, studied it extensively with an eye to adapting it to the SSME, This combined design is referred to as the RS-25e. Best of both worlds, higher performance, lower cost. SSME has better thrust, equal isp. With the proposed changes, restarting the RD-0120 production would cost more, take longer, and give you an engine with less performance.
Something I noticed as well. The SSME is not *that* much less thrust than an RS-68, only 25% less. The RD-0120, however, is 45% less than the RS-68. With the SSME's better isp, it still wins. If we do follow NASA's plan to reduce the cost to produce by adapting technologies from other engines, there is no compelling argument against the SSME in my opinion.
RS-0120 has a better Isp than the SSME.
SSME sea level thrust@ 109% power is at 419K lbf, so that's only 63% of RS-68A, the RD-0120 sea level thrust is at 341K, at 51% of RS-68A.
Where are you getting the stats for the RS-68A, as it's not yet published? I've been comparing against the RS-68, which makes your comparison far weaker.
QuoteBut that makes the RD-0120 a better fit as a replacement of RS-68s.
Two RD-01020 is just about identical as one RS-68A thrust, therefore minimum structural modification on the CBC other than the obvious (2 engine feed & gimbals). At a significantly higher Isp, itwill make the Delta-IV a higher performance vehicle with minimum mods.
You'd still have to restart production, and you would have the situation of the RD-180 off of Atlas, a foreign made engine.
QuoteSSME, on the other hand, will require way too much throttling than currently capable.
As far as on currently in production, well; 1) the market place is a tremendous motivator, and 2) SSME is currently not in production either. Just try to find the toolings for them.
As for the "NASA studies", there's a huge difference between "study" and "done it".SSME has a wider throttling range than both RS-68 and RD-0120, so not certain what you are referring to. There has even been discussion of further pushing it's thrust.
Also, SSME can burn for a longer range than RS-68, compare the vac thrust and you find the RS-68 not as strong.
Now, you're still paying for startup and R&D costs in either case (RD-0120 and RS-25e) but one would give us more thrust, and have a domestic production history to work from.
Where are you getting the stats for the RS-68A, as it's not yet published? I've been comparing against the RS-68, which makes your comparison far weaker.
If that is the case, then your numbers are full of mistakes.
RS-68 sea level thrust is 650K lbf.
QuoteQuoteBut that makes the RD-0120 a better fit as a replacement of RS-68s.
Two RD-01020 is just about identical as one RS-68A thrust, therefore minimum structural modification on the CBC other than the obvious (2 engine feed & gimbals). At a significantly higher Isp, itwill make the Delta-IV a higher performance vehicle with minimum mods.
You'd still have to restart production, and you would have the situation of the RD-180 off of Atlas, a foreign made engine.
and that has been a problem for National Security payload launches how?
QuoteQuoteSSME, on the other hand, will require way too much throttling than currently capable.
As far as on currently in production, well; 1) the market place is a tremendous motivator, and 2) SSME is currently not in production either. Just try to find the toolings for them.
As for the "NASA studies", there's a huge difference between "study" and "done it".SSME has a wider throttling range than both RS-68 and RD-0120, so not certain what you are referring to. There has even been discussion of further pushing it's thrust.
Also, SSME can burn for a longer range than RS-68, compare the vac thrust and you find the RS-68 not as strong.
Now, you're still paying for startup and R&D costs in either case (RD-0120 and RS-25e) but one would give us more thrust, and have a domestic production history to work from.
Americanization of Russian engines is no longer a myth. We are not comparing SSME with RS-68, we are comparing the SSME with RD-0120 as option to replace the RS-68s, also as core engines for the SLS LO2/LH2 option.
In this case, more thrust is not necessary better.
For throw-away engines, cost is a big issue.
Source for a $28M SSME? Non-credible in my estimation.
Source for a $28M SSME? Non-credible in my estimation.If you wish to call NASA a liar, feel free. That is the cost estimate put forward last year in their SD-HLV study papers. They've had cost estimates out since 2003, and PWR has reams and reams of documentation for it if you want to ask them nicely for it. (Which is what I did)
The RS-25e is a well documented upgrade path to the existing RS-25d SSME engine. It incorporates numerous upgrades, and system elimination methods, to bring the cost of the engines down. If you're calling it non-credible, you should call the cost estimates of the RS-68A non-credible, for the same people did both.
Source for a $28M SSME? Non-credible in my estimation.If you wish to call NASA a liar, feel free. That is the cost estimate put forward last year in their SD-HLV study papers. They've had cost estimates out since 2003, and PWR has reams and reams of documentation for it if you want to ask them nicely for it. (Which is what I did)
The RS-25e is a well documented upgrade path to the existing RS-25d SSME engine. It incorporates numerous upgrades, and system elimination methods, to bring the cost of the engines down. If you're calling it non-credible, you should call the cost estimates of the RS-68A non-credible, for the same people did both.
Antares is saying that anything done before the SSME shut down is no longer applicable and yes, it applies to the RS-68. It is much more expensive now.
Source for a $28M SSME? Non-credible in my estimation.If you wish to call NASA a liar, feel free. That is the cost estimate put forward last year in their SD-HLV study papers. They've had cost estimates out since 2003, and PWR has reams and reams of documentation for it if you want to ask them nicely for it. (Which is what I did)
The RS-25e is a well documented upgrade path to the existing RS-25d SSME engine. It incorporates numerous upgrades, and system elimination methods, to bring the cost of the engines down. If you're calling it non-credible, you should call the cost estimates of the RS-68A non-credible, for the same people did both.
Antares is saying that anything done before the SSME shut down is no longer applicable and yes, it applies to the RS-68. It is much more expensive now.Right now, it's all a bit of an unknown. I used the best data available for the discussion, which was current as of 9 months ago. Whenever they post new information, I'll go by that.
But right now, almost all rocket costs have been going up, no matter the company or even country.