Will NASA SLS Rocket survive when ARES did not?

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• Those are all good points Nate Downes made, definitely knows his stuff. The question still is does SLS just cost to much to exist where there are alternatives. Will the Falcon really be able to deliver what they say? Even if commercial rockets are more they are still relatively cheap compared to the SLS. I was lucky enough to see 2 Saturn 5 rockets launch in person and I would love nothing more than to see something like that again but perhaps the commercial market now has a better answer. In the 60s that was just not an option. Just for arguments sake if we took the billions saved what else could NASA do with that? Send someone to moon? Send robots to Mars, Europa?
  Is the cost of the SLS, as awesome as a machine as it would be, really worth it when NASA has such a tight budget to begin with? The big version not being ready until 2030....18 years from now...18 years...Is the progress of manned space really slowing down so much that we are willing to wait 18 more years for this to develop...that's 61 years after we walked on the moon.
  I remember someone said back in the Apollo era that rocket fuel did not put man on the moon, money did. That stuck with me as a child and it is not far from the truth. What NASA really needs is money and to get that they need to inspire the American taxpayer. The real trick is how to do that so the money and projects will follow.

• You have a few errors here. Error 1:

  Lift Capacity

  Ares V 188 metric tons, SLS 130 metric tons. The Ares V actually had a larger lift capacity.

  This is from a mis-understanding of payload in both vehicles for the target mission. LEO payload means nothing, it is either earth depature, or trans-lunar payloads which are the point here. That 188 metric ton Ares V lift capacity was mostly due to the fuel needed for its inefficient EDS stage, required due to its commonality with the Ares I. It delivered to earth departure only 64 metric tons of actual payload to lunar orbit. The SLS can deliver over 70 metric tons of actual payload to lunar orbit, due to its separation of earth departure and second stage duties due to the elimination of the weakest link.

  "SLS design will use the RS-25D/E engines from the Space Shuttle Program for the core stage and the J-2X engine for the upper stage. Hmmmm….ARES was going to use the RS-68 as they are less complex and less expensive. What changed that the SLS program decided to use the more expensive and complex Shuttle engines?"

  That the rocket had to lift people is what changed. The RS-68 is not designed for human rating. It is no more dangerous than the RS-25, but the RS-68 lacks the ability to add the sensors to tell the abort computer that "hey, your rocket is going to blow up." This is an intentional design of the RS-68, it was never designed for human use, and a cargo mission does not need to know that it is failing in real time, a slight delay is sufficient as the cargo is lost anyways. The cost to re-design the RS-68 for human flight is so severe, and the final engine cost estimate so great, and the commonality with the existing RS-68 engine so little, that you would be basically designing a whole new engine for little gain. Now, that being said, there is something else about the RS-25 that is overlooked, the RS-25D (entered service in 2006) is primarily expensive for three reasons. 1) It is procured at a rate of 1 engine every 28 months 2) For re-use purposes, the engine components need to be able to be inspected between flights, and disassembled if need be and 3) it still utilizes a few components which date back to the 1970's and 1980's, such as the control computer and nozzles. In 2001, development began on the Block III upgrade program, which addressed two of these issues. Block III, also called RS-25E, hit the component testing level when it was shut down in order to fund Constellation. It replaced the last RS-24 component, the nozzle, with one which could be manufactured by machine (the nozzle is currently hand-made). It also replaced the computer system with a modern system. When the Block III program was shut down, many parts of the RS-25E were carried forward to the J-2X, namely the computer system and the automated nozzle fabrication technology, which means that these components can now be carried back to the RS-25E having been fully developed and tested in another engine. This also means that the cost to produce both engines is reduced due to this sharing of overhead (which many parts of are also shared with the RS-68, such as the same tools and people making the combustion chamber for all three engines as well as the under development RL-10C). This is not unheard of, and is actually fairly common in many fields. These changes, combined with an improved production schedule, would reduce the RS-25E to a more reasonable expense, and less than the cost of a redesigned human-rated RS-68 derived engine.

  As for Saturn being cancelled due to high operational costs, this is also false. The Saturn rocket was not as expensive as many people assume, as they fold in the R&D over the few flights and in many cases ignore the Saturn I and IB launches entirely despite the same R&D costs applying to both. But studying the procurement records, per launch, the Saturn V was quite reasonable at the end of its lift. They had been, over the lifetime of operation, working on cost reduction strategies, so SA-514 cost only half what SA-505 did, and the cost for SA-520 was already agreed to, reducing the cost of Saturn even further, to a grand total of ~$320 million per launch (adjusted to 2005 dollars). Had the program continued, the replacement of the Saturn IB with the Saturn II (which replaced the IB's unique first stage with a stage derived from the Saturn V's second stage, powered by HG-3 engines, the ancestor of the SSME) the cost efficiency would have been further improved. But killing the program so young instead resulted in artificially high costs, due to the amount of R&D needed.

  You did at least admit that the costs of SLS included non-SLS costs, such as Orion and launch pads, but ignored that the launch pad upgrades are for more than just the SLS, and would be there for a pure commercial operation as well. NASA is undergoing the process of converting the whole complex to a program called the 21st Century Space Complex, and would be servicing Falcon, Atlas, Delta, Taurus, any launch vehicle. This can be done due to LC-39's original flat pad design, which is being restored now. Instead of building a new launch complex for each vehicle, you build an adapter to the mobile platform, or use your own launch platform. The papers on this came out last year, and gave great insight into the whole program. LC-39's main cost is due to low use. The 21st Century program addresses this issue, opening it up to a lot of utilization.

  As for missions being low in number, you can thank the budget cuts for that one. NASA is operating within a new paradigm, design your mission scope with a 70% budget target. That means, rather than the old paradigm of having a 50% chance of hitting your budget, which means half of the time you run over, they now design around 70% chance of hitting their budget. This means they can pencil in less missions up front, but have a great chance of having more funds left over which means that they can add more missions later on. A prime example of this is the Orbital Test Flight penciled in for 2013/2014, where an unmanned Orion will be launched onboard a Delta IV rocket. Per the budget, they could never afford it, but they came in under budget for several pieces, resulting in being able to deliver an extra, unexpected mission.

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