So, in effect you are saying Griffin lied, as it did not come in a close second, and instead came in near the bottom. By switching, he guaranteed the budget issues. And no, if they had stayed, the cancellation is not a foregone conclusion. For one, Orion would not have needed 9 redesigns, and the billions that consumed. Another, the initial launch had a better chance of being done on time, and a flying launch system is difficult to cancel.
By dismantling NASA infrastructure now, especially during this long decade-plus of economic stagnation, he is having the ultimate say in NASA's future. Who's going to rebuild it once its gone?
Quote from: Downix on 09/07/2011 04:39 amSo, in effect you are saying Griffin lied, as it did not come in a close second, and instead came in near the bottom. By switching, he guaranteed the budget issues. And no, if they had stayed, the cancellation is not a foregone conclusion. For one, Orion would not have needed 9 redesigns, and the billions that consumed. Another, the initial launch had a better chance of being done on time, and a flying launch system is difficult to cancel.You must be reading a different ESAS report than I am reading. (Different from the one Mr. Griffin read also.) Mine shows that five segment-J-2S outperforms four segment-SSME (Figure 6-95). Mine shows that the five segment rocket costs more to develop (nothing like twice as much as claimed elsewhere in this thread), but costs less to fly. Mine says nothing about an RS-68 powered Ares V (costs or performance), so offers no comparison of the savings that would result from its use. - Ed Kyle
You just destroyed your own argument. You just admitted that it shows that it costs more to develop, 39% more according to the ESAS report. And yes, it costs 6% less to fly. As for an RS-68 powered Ares V, you're glossing over the LV28 grouping, including the ones which utilize the larger tank and 5-segment SRB, included in the ESAS Appendices but not in the main report. The Appendices are in L2 is you need a refresher.
Quote from: Downix on 09/07/2011 05:11 amYou just destroyed your own argument. You just admitted that it shows that it costs more to develop, 39% more according to the ESAS report. And yes, it costs 6% less to fly. As for an RS-68 powered Ares V, you're glossing over the LV28 grouping, including the ones which utilize the larger tank and 5-segment SRB, included in the ESAS Appendices but not in the main report. The Appendices are in L2 is you need a refresher.I haven't argued that 5-segment/J-2X cost less than 4-segment/SSME to develop. I've argued that its use lowered total program costs for the complete Ares I/V architecture. In addition, the J-2X Ares I cost less to fly than the SSME Ares I. Over time, those savings would have added up. The savings weren't just 6%, they were 7% for production and 15% for operations.
Quote from: edkyle99 on 09/07/2011 09:28 pmQuote from: Downix on 09/07/2011 05:11 amYou just destroyed your own argument. You just admitted that it shows that it costs more to develop, 39% more according to the ESAS report. And yes, it costs 6% less to fly. As for an RS-68 powered Ares V, you're glossing over the LV28 grouping, including the ones which utilize the larger tank and 5-segment SRB, included in the ESAS Appendices but not in the main report. The Appendices are in L2 is you need a refresher.I haven't argued that 5-segment/J-2X cost less than 4-segment/SSME to develop. I've argued that its use lowered total program costs for the complete Ares I/V architecture. In addition, the J-2X Ares I cost less to fly than the SSME Ares I. Over time, those savings would have added up. The savings weren't just 6%, they were 7% for production and 15% for operations. The 5-segment/J-2X approach certainly lowered total program costs for the complete Ares I/V architecture, but probably not in the way that its proponents intended.It looks like there was never support for a grandiose back-to-the-moon effort which meant that the theoretical program cost savings from commonality between Ares I and Ares V would never materialize.Was this foreseeable at the time? Or was an Ares I / Orion that could only go to ISS for years considered not much better than no NASA human spaceflight at all?
The main thing that is needed to fix Ares I's design two large kerolox engines of around 1 million lbs thrust also would simplify Atlas Phase II.Even a dinosaur of a design such as the F-1A would seriously improve performance and safety.Though the lower ISP would hurt Atlas vs the RD-180 that and the F-1 is built completely differently from modern engines.I kinda like the idea of making a modern Jarvis with the Ares I upper stage.
Quote from: Patchouli on 09/09/2011 01:23 amThe main thing that is needed to fix Ares I's design two large kerolox engines of around 1 million lbs thrust also would simplify Atlas Phase II.Even a dinosaur of a design such as the F-1A would seriously improve performance and safety.Though the lower ISP would hurt Atlas vs the RD-180 that and the F-1 is built completely differently from modern engines.I kinda like the idea of making a modern Jarvis with the Ares I upper stage.indeed, a single F-1A using a stretched 5.5m tank would have met every single criteria listed in esas, and beaten the 5-segment srb in safety and performance even by the odd standards they used.
Quote from: Downix on 09/09/2011 01:43 amQuote from: Patchouli on 09/09/2011 01:23 amThe main thing that is needed to fix Ares I's design two large kerolox engines of around 1 million lbs thrust also would simplify Atlas Phase II.Even a dinosaur of a design such as the F-1A would seriously improve performance and safety.Though the lower ISP would hurt Atlas vs the RD-180 that and the F-1 is built completely differently from modern engines.I kinda like the idea of making a modern Jarvis with the Ares I upper stage.indeed, a single F-1A using a stretched 5.5m tank would have met every single criteria listed in esas, and beaten the 5-segment srb in safety and performance even by the odd standards they used.Too bad it would be a new engine program if brought back though I guess two RS-84s or TR-107 also would work.The two RS-84s or even two RD-180s probably would be more expensive per flight then one F-1A but two TR-107s might actually be cheaper.
I did decide to calculate what would one F-1A lift using this rocket calculator.http://www.silverbirdastronautics.com/cgi-bin/LVPcalc.plAssuming the stage would be over all half the mass of a Jarvis 1 I got 23MT.Just barely enough to lift Orion.Though Orion can act as a third stage so this is probably not as bad as it seems.Still can the F-1A be made with a modern nozzle without messing things up too much?I guess for cheapness do the whole thing in channel wall as modern flight avionics probably would more then make up for the extra weight.
Quote from: Patchouli on 09/05/2011 03:39 amQuote from: Lars_J on 09/04/2011 11:50 pmSlavish devotion to "simple" is exactly what led down the Ares I path. And the end result was a whole system which was NOT simple.The pretty much sums it it up.The people running the project would not change the design when it became obvious it was the wrong direction.If the people doing Apollo had the same stubborn mindset we may have never landed on the moon and certianly would not have done so before the end of the decade.Apollo originally was going to use a direct landing LOR was the underdog at first.Kinda like Direct vs Ares.The 1961 vehicle was a cluster of Saturn C-3 first stages with super upper stages.
Quote from: Lars_J on 09/04/2011 11:50 pmSlavish devotion to "simple" is exactly what led down the Ares I path. And the end result was a whole system which was NOT simple.The pretty much sums it it up.The people running the project would not change the design when it became obvious it was the wrong direction.If the people doing Apollo had the same stubborn mindset we may have never landed on the moon and certianly would not have done so before the end of the decade.Apollo originally was going to use a direct landing LOR was the underdog at first.Kinda like Direct vs Ares.
Slavish devotion to "simple" is exactly what led down the Ares I path. And the end result was a whole system which was NOT simple.
Quote from: Lars_J on 09/05/2011 05:48 amThere's a lot more to consider than the plain number of engines. You can have drastically different designs that both have two engines. In Ares 1's case the issue is compounded by a very poor first stage decision. (And looking at the number of small thrusters that have to fire during its ascent, and for its stage separation - one could actually argue that it has a LOT of engines that HAVE TO work)Ares I uses a roll control thruster as I understand it, not a bunch of small thrusters, at least during first stage flight. The second stage has thrusters, but so does Centaur (Centaur has 12 monopropellant thrusters for pitch, yaw, roll).An Atlas V core fires eight stage separation motors. Heavy would fire even more ordnance.Atlas V Heavy would have more engines (high chamber pressure staged combustion engines on the cores), more separation events, more points of failure, and more complexity. - Ed Kyle
There's a lot more to consider than the plain number of engines. You can have drastically different designs that both have two engines. In Ares 1's case the issue is compounded by a very poor first stage decision. (And looking at the number of small thrusters that have to fire during its ascent, and for its stage separation - one could actually argue that it has a LOT of engines that HAVE TO work)
Quote from: edkyle99 on 09/05/2011 06:58 pmQuote from: Patchouli on 09/05/2011 05:56 amBoth Ares I and V had serious design issues that made them unviable designs.I don't see the Ares I design in particular as nonviable.It was. The premise behind Ares-I was to take two existing engines and use their extensive flight experience to make a simple, reliable rocket for Orion. Then they discovered their choice for the second stage engine (SSME) wouldn't work and that they'd have to design a new second stage engine. Then they discovered that the new engine wasn't going to give the performance of the original so they'd have to design a new first stage engine as well. So the entire premise was falsified and the entire project should have been re-evaluated at that point. Instead, they chose to push forward on a project that was in direct violation of its original design premise. To me, that's non-viable unless there are very compelling cost and reliability reasons it isn't. In this case, it was going to be very expensive and not necessarily reliable because of all the technical problems and their solutions, and the total lack of flight experience with either stage or either engine.
Quote from: Patchouli on 09/05/2011 05:56 amBoth Ares I and V had serious design issues that made them unviable designs.I don't see the Ares I design in particular as nonviable.
Both Ares I and V had serious design issues that made them unviable designs.
Ares 1 design intent was to drastically increase crew safety during ascent.
Quote from: Downix on 09/05/2011 04:46 amQuote from: Patchouli on 09/05/2011 03:39 amQuote from: Lars_J on 09/04/2011 11:50 pmSlavish devotion to "simple" is exactly what led down the Ares I path. And the end result was a whole system which was NOT simple.The pretty much sums it it up.The people running the project would not change the design when it became obvious it was the wrong direction.If the people doing Apollo had the same stubborn mindset we may have never landed on the moon and certianly would not have done so before the end of the decade.Apollo originally was going to use a direct landing LOR was the underdog at first.Kinda like Direct vs Ares.The 1961 vehicle was a cluster of Saturn C-3 first stages with super upper stages. Do you have a link to a study or paper showing that?? I'd LOVE to see it! Any information greatly appreciated! OL JR