I got thinking the other day (dangerous, I know), about how you could replace the (soild) first stage of the Ares I with a drop-in liquid replacement.
R&R - 13/7/2006 2:51 PMQuoteyinzer - 13/7/2006 10:03 PMThe lack of graceful emergency thrust termination can give higher LOC numbers with very detailed modeling - it makes aborts much more dynamic events. The numbers are small enough that it's hard to make any sort of statistical judgement, and the probabilistic risk assessments made to date for the shuttle have all been wildly optimistic.In any case, according to NASA Watch, MSFC is considering going to the RD-180 for the CaLV core stage. And as long as they're doing that, they might as well go to a 2 RD-180 core stage for the CLV. If they call it Atlas Phase 2 there's already a bunch of paperwork and promotional material available. NASA Watch also says that there's consideration of dumping the CLV for an EELV because the CLV is having trouble lifting the CEV and is costing way more than was expected.Did you find something more than the "hallway chatter" that I see described on NASA Watch?I have a hard time believing NASA would make another significant design change like they did going from Revised Shuttle to RS68 engines, especially going to RD180's. Since PW&Rocketdyne are very far from building them in the US if ever I wonder if NASA can avoid the political backlash of once again relying on the Russians as significantly as they have been with Soyuz flights to ISS.
yinzer - 13/7/2006 10:03 PMThe lack of graceful emergency thrust termination can give higher LOC numbers with very detailed modeling - it makes aborts much more dynamic events. The numbers are small enough that it's hard to make any sort of statistical judgement, and the probabilistic risk assessments made to date for the shuttle have all been wildly optimistic.In any case, according to NASA Watch, MSFC is considering going to the RD-180 for the CaLV core stage. And as long as they're doing that, they might as well go to a 2 RD-180 core stage for the CLV. If they call it Atlas Phase 2 there's already a bunch of paperwork and promotional material available. NASA Watch also says that there's consideration of dumping the CLV for an EELV because the CLV is having trouble lifting the CEV and is costing way more than was expected.
SMetch - 14/7/2006 10:37 AMThe RD180 would essentially get rid of ATK and Boeing at the same time in favor of Lock/Mart.
Jim - 13/7/2006 4:23 PMLanding of an orbiter has nothing to do with the delivery of a satellite. I am going to harsh again, but it is the same as the failure of the SRB parachutes on STS-4. The SRB's were not recovered. Is this a mission failure."The traditional description of "payload" is orbited, separated mass" is wrong. Payload adapters, spintables, dual payload adapter assemblies are payload mass and not separated. The cradles of the spacecraft that used to fly on the shuttle were not separated. If the cradle was a damaged........ aeroshells and parachute are part of the spacecraft and not equivilent to the shuttle orbiter.
Avron - 14/7/2006 10:35 AMMaybe just maybe, it may happen if ATK gets SRB for for CaLV... but don't hold your breath.. however, I think the division of work, could be in line with your thinking
quark - 17/7/2006 11:21 PMQuoteAvron - 14/7/2006 10:35 AMMaybe just maybe, it may happen if ATK gets SRB for for CaLV... but don't hold your breath.. however, I think the division of work, could be in line with your thinkingAt some point, you have to quit the political engineering and find a technical solution that works. So far, NASA has been tying themselves in knots keeping SRM's as the centerpiece for launch. Why? Did ATK win a competition? When they had to compete at the beginning of the EELV competition, they lost first round.
JIS - 18/7/2006 5:19 AM...When you want to go to Moon or Mars you need super heavy lift vehicle. ...
JIS - 18/7/2006 8:19 AM1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)2. go with Ares 1 and Ares V
Jim - 18/7/2006 7:39 AMQuoteJIS - 18/7/2006 8:19 AM1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)2. go with Ares 1 and Ares V It's not either/or. The stick is not need for the CaLV.
lmike - 18/7/2006 7:25 AMQuoteJIS - 18/7/2006 5:19 AM...When you want to go to Moon or Mars you need super heavy lift vehicle. ...First of all what is exactly a "super heavy lift vehicle"?
JIS - 18/7/2006 9:08 AMQuoteJim - 18/7/2006 7:39 AMQuoteJIS - 18/7/2006 8:19 AM1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)2. go with Ares 1 and Ares V It's not either/or. The stick is not need for the CaLV.But it's needed for Ares V.Or do you think that there will be enough resources to develop and prepare Moon stuff for Ares V before 2018?
JIS - 18/7/2006 7:19 AMQuotequark - 17/7/2006 11:21 PMQuoteAvron - 14/7/2006 10:35 AMMaybe just maybe, it may happen if ATK gets SRB for for CaLV... but don't hold your breath.. however, I think the division of work, could be in line with your thinkingAt some point, you have to quit the political engineering and find a technical solution that works. So far, NASA has been tying themselves in knots keeping SRM's as the centerpiece for launch. Why? Did ATK win a competition? When they had to compete at the beginning of the EELV competition, they lost first round. The point is:When you want to go to Moon or Mars you need super heavy lift vehicle. And there is already one – STS (thanks to SRB). You would need around 10 x RD-180 to match Saturn V first stage. So the choice is:1. go with Atlas phase 2 as CLV and Atlas phase 3 as CaLV (or better 10 x RD-180 in one core first stage) (or resurrect F1)2. go with Ares 1 and Ares V
josh_simonson - 18/7/2006 8:10 PMThe core stage of the Aries V with RS-68s and 10m tank has enough fuel fraction to send CEV to ISS in a single stage that NASA intends to build anyway. Launching crew on the Aries V core would double it's economies of scale because crew/cargo LVs roll off the exact same assembly line, and developing the CLV will get halfway to having an HLV. This would put NASA's ducks in a row instead of scattered willy-nilly tinkering with ELVs or designing dead-end rockets with components that don't exist yet. No other CLV option also serves to make the HLV significantly cheaper.