JIS - 16/11/2007 3:39 AMQuotekraisee - 16/11/2007 5:43 AMAlso there are recurring cost implications too. Every extra J-2X adds about $25m to the cost of each mission. Add 4 and your per-mission costs would increase by $100m, which given the current LV variable cost will be in the ballpark of $400-450m, is quite an impact.I agree at this point that 2 J-2X engines on EDS is not a good idea. It would be far better and cheaper to increase J-2X thrust and ISP.QuoteWhile lots of trade studies are going on, the only sure thing is that *something* has to change with Ares-I/V if NASA wants to achieve its currently planned missions. Currently they are well below the line (~20%) performance-wise from closing the performance box using the current configuration of the launchers. I'm on record for how I'd like to see them change, but I don't know which way they will jump. I agree that more payload delivered to the moon the better. I think that for Lunar base construction and supply the key is a payload delivered in one launch. Therefore, I'm glad to see Ares V growing bigger. Hopefully the payload capability will increase as well.10 m fairing is a very good news for base line LSAM (minimum ascend stage) and LSAM cargo derived from descend stage. QuoteOnly time will tell that, but I am convinced that time is a commodity which we are seriously running out of.Ross.The time is tight for J-2X development to get Orion/Ares 1 up and running to support ISS. There is no doubt that Orion/Ares 1 is more than enough for that. There is plenty of time for LSAM and Ares V development.
kraisee - 16/11/2007 5:43 AMAlso there are recurring cost implications too. Every extra J-2X adds about $25m to the cost of each mission. Add 4 and your per-mission costs would increase by $100m, which given the current LV variable cost will be in the ballpark of $400-450m, is quite an impact.
While lots of trade studies are going on, the only sure thing is that *something* has to change with Ares-I/V if NASA wants to achieve its currently planned missions. Currently they are well below the line (~20%) performance-wise from closing the performance box using the current configuration of the launchers. I'm on record for how I'd like to see them change, but I don't know which way they will jump.
Only time will tell that, but I am convinced that time is a commodity which we are seriously running out of.Ross.
luke strawwalker - 27/11/2007 4:49 AMupscaling the J-2 to higher thrust/ISP would be a LOT better than slapping a second one on. Increasing the size of the J-2 to something closer to the SSME's performance (dunno, maybe halfway between the old/currently envisioned J-2 and SSME) would not only help Ares I by giving it more thrust but would save money down the road, because one souped up engine will undoubtedly be cheaper than two dinkyer ones. I'm sure it would increase the cost of the J-2 in the short term but it would be more than worth it in the long term. Besides the J-2 is mostly on paper at this point, and it'd be FAR easier and cheaper to choose the right size to build it NOW than later on after it's built, or having to use a second one on every EDS. JMHO! OL JR
meiza - 16/11/2007 2:35 PMIt's like saying NASA should have gone to NOVA with eight F-1 engines, and launched one every month, that would have costed so little but the stupid politicians didn't think far enough. Urgh.
CFE - 24/11/2007 3:51 PMAgreed, Jorge. It does beg the question of whether a Saturn V-only production line could have made the cut, replacing the Saturn IB with an S-IC + S-IVB vehicle. It's doubtful, though.As fas as Jeff Bell goes, I must say that I will agree with at least the first half of a Jeff Bell editorial/screed. Then he takes a logical turn that's unexpected and extreme, with flimsy evidence to support. That's the point where he loses me. But he was totally correct to suggest that "shuttle derived" would evolve into something that has little or no shuttle heritage at all. We still haven't gotten to his predicted "EELV derived" solution, though.
kraisee - 16/11/2007 2:05 PMI think Ares-I is a long way below the sweet spot, and Ares-V is a long way beyond it. Which leads me to a conclusion that its somewhere in between. And we all know where that line of thought leads...Ross.
Sid454 - 11/2/2008 10:33 PMI don't think the change from 27 to 33feet will be an issue for infrastructure but the larger faring could be great for the LSAM and allow it to be a shorter wider design which is better for both stability and safety of the astronauts.
spacenut - 29/11/2007 6:37 AMThere were plans to recover, with parachutes, the Saturn V first stage. There was also plans to increase the F-1 engine to 2.2 million lbs. of thrust (11 million total), which is the limit of the launch pads today. The J-2 was to be upgraded from 200,000 lbs of thrust to 275,000 lbs of thrust. This would have made the Saturn V capable of between 150-175 tons to LEO. This would have reduced costs/lb to orbit, and with a reusable first stage, costs could have probably been further reduced. The J-2 hardware was to make a plug nozzle engine for the 3rd stage, so it could have been made reusable, by using it as a heat shield. The second stage could probably have been made the same and recovered. The upgrades may have made the Saturn V sustainable. Also, from what I have read, the cost to launch a Saturn I was about the same as the Saturn V.
kraisee - 11/2/2008 11:45 PMAll of this adds up to a seriously extensive amount of change which will be required to support the new 33ft diameter stage configuration on Ares-V.Ross.
Sid454 - 11/2/2008 9:33 PM...maybe trying to make the biggest rocket possible but instead the biggest one that can find a good flight rate and escape the Saturn V's fate ...
mikeh - 12/2/2008 8:50 AMThe flight rate didn't kill the Saturn V, Nixon and Congress with their lack of funding and canceled programs did the job.
Sid454 - 11/2/2008 7:33 PMthe larger faring could be great for the LSAM and allow it to be a shorter wider design which is better for both stability and safety of the astronauts.
But on cost I have to agree with clongton here flight rate is everything in costs so maybe we shouldn't be trying to make the biggest rocket possible but instead the biggest one that can find a good flight rate and escape the Saturn V's fate if that means two big launches vs one big one and one small one so be it.
My biggest fear with Ares is the program could be canceled before Ares V flies and then we would be stuck in LEO in a situation a lot worse then the one we are in now.
Also JPL will get screwed out of an opportunity to have an HLLV to play with and I'd like to see things like an 8M optical space telescope and a Jupiter icy moon orbiter.Also being able to perform missions with out those time wasting gravity assist flybys would be great.