CFE - 28/4/2007 6:47 AM(aside from silly concerns about Atlas's Russian engine.)
clongton - 28/4/2007 7:18 AMHow many RD-180's are on-hand, and how many are still in the pipeline?How many are LM going to need for the forseeable future?Is the RD-180 still being produced ONLY in Russia and if so, what is the likelyhood that PWR will be licensed to do the production stateside?
Antares - 28/4/2007 10:46 AMQuoteclongton - 28/4/2007 7:18 AMHow many RD-180's are on-hand, and how many are still in the pipeline?How many are LM going to need for the forseeable future?Is the RD-180 still being produced ONLY in Russia and if so, what is the likelyhood that PWR will be licensed to do the production stateside?20ish, 70ishTotal order was 101.Only in Moscow. Some technical uncertainty, MUCH financial uncertainty.
MATTBLAK - 28/4/2007 10:54 PMMy recipe:Create Atlas V, Phase 2 (5.4m diameter corestage, 2x RD-180 - Upper Stage; 1x J-2X). No need for Ares 1, but work done on Ares 1 second stage not wasted. This would be a very good CLV.
Christine - 30/4/2007 10:17 AMQuoteMATTBLAK - 28/4/2007 10:54 PMMy recipe:Create Atlas V, Phase 2 (5.4m diameter corestage, 2x RD-180 - Upper Stage; 1x J-2X). No need for Ares 1, but work done on Ares 1 second stage not wasted. This would be a very good CLV.Or you can use the RL-10 or RL-60 which will give you engine out, better isp, and save you a billion on engine development.
Director - 4/5/2007 6:32 PM"The RD-180 is the best rocket engine on earth. It far out strips the RS-68 or SSME. It just so happens to be designed and built by Russians."Which explains why an RD-170 recently failed spectacularly, and why an SSME has a much higher exhaust velocity, is reusable, and has flown in excess of 330 times with very few mishaps, none of them catastrophic.
Christine - 1/5/2007 1:17 AMQuoteMATTBLAK - 28/4/2007 10:54 PMMy recipe:Create Atlas V, Phase 2 (5.4m diameter corestage, 2x RD-180 - Upper Stage; 1x J-2X). No need for Ares 1, but work done on Ares 1 second stage not wasted. This would be a very good CLV.Or you can use the RL-10 or RL-60 which will give you engine out, better isp, and save you a billion on engine development.
MATTBLAK - 5/5/2007 12:52 AMQuoteChristine - 1/5/2007 1:17 AMQuoteMATTBLAK - 28/4/2007 10:54 PMMy recipe:Create Atlas V, Phase 2 (5.4m diameter corestage, 2x RD-180 - Upper Stage; 1x J-2X). No need for Ares 1, but work done on Ares 1 second stage not wasted. This would be a very good CLV.Or you can use the RL-10 or RL-60 which will give you engine out, better isp, and save you a billion on engine development.Cluster of 5x RL-10-B2 engines weight: 3320 pounds, thrust: 125,000 pounds. Isp -- 462 seconds.5x RL-60 engines weight: 5500 pounds, thrust: 300,000 pounds. Isp -- 465 seconds.1x J-2X weight: 4000 pounds (approx.), thrust: 290,000 pounds. Isp -- 448 seconds (goal).Conclusion? Standard RL-10 too weak, RL-10-B2 better but 5x thrust still far inferior to 1x J-2X or cluster of RL-60s. 1x J-2X lowest structural weight and simplest plumbing. 5x RL-60s a reasonable alternative, but higher weight and complexity of multiple engine cluster hauled to space impacts payload amount and reliability statistics, despite a desirable engine-out ability. And would a cluster of 6x RL-60s on a 5.4 meter diameter stage be feasible. Would they fit? I'll have to look into that.
Director - 5/5/2007 6:50 AM"What does higher exhaust velocity give you as far as performance?" The ability to get to orbit, for one thing. (...)
"What does higher exhaust velocity give you as far as performance?"
The ability to get to orbit, for one thing.
http://www.lockheedmartin.com/data/assets/12382.pdf
(See above) Yes! I'm reminded now that up to 6x RL-10 derivatives can fit on an ICES 5.4m diameter stage. Since the RL-60 and RL-10 series are supposed to be very similar in dimensions, I would imagine that a cluster of six RL-60s would make a very high performance stage -- the superior Isp and thrust of the 6x RL-60s making up for the mass of the six engines (6x RL-60s weighs 6600 pounds, 360000 lbs thrust and 465 seconds Isp, VS 1x J-2X weighing 4000 pounds with 294000 pounds thrust and 448 seconds Isp).Apples and oranges, you could say.
Director - 4/5/2007 10:50 PM"What does higher exhaust velocity give you as far as performance?" The ability to get to orbit, for one thing.
"What's the cost to refurbish two SSME's vs. the cost of a new RD-180?" We'll need to transition to full flow engines with channel wall nozzles.
"What's the cost to refurbish two SSME's vs. the cost of a new RD-180?"
We'll need to transition to full flow engines with channel wall nozzles.
Director - 4/5/2007 7:32 PM"The RD-180 is the best rocket engine on earth. It far out strips the RS-68 or SSME. It just so happens to be designed and built by Russians."Which explains why an RD-170 recently failed spectacularly, and why an SSME has a much higher exhaust velocity, is reusable, and has flown in excess of 330 times with very few mishaps, none of them catastrophic.