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Rick
07-05-2008, 10:21 AM
(flatoday.com) A transportation system some claim would take America back to the moon faster and cheaper than Ares rockets would lack the propulsive oomph to get the job done and in the end would delay an effort to send U.S. astronauts back to the lunar surface, internal NASA documents show.
The contention that the so-called DIRECT architecture would save money and be safer lacks "supporting data and analysis" and the transportation system developed for Project Constellation is more suitable for NASA's envisioned lunar missions, the agency documents say.
"NASA has determined that the DIRECT proposal is unlikely to achieve its claims of improved performance, safety and development costs when compared to the Ares I and Ares V approach. In addition, the limited data available in the online DIRECT proposal do not support the claims of increased safety," NASA said in a summary you can see HERE (http://www.nasa.gov/pdf/256922main_Direct_vs_%20Ares%20_FINAL_62508.pdf).
What's more, agency analyses show that "the DIRECT proposal would cost more than the Ares family in the near-term and also on a recurring launch basis," the report says. "Finally, the DIRECT proposal would take longer to develop when compared to the Ares vehicles when factoring in the extensive core stage development effort and associated acquisitions."
The DIRECT proposal was the result of a grass roots effort spearheaded by a model-rocket maker and purportedly supported by many NASA mid-level engineers and managers in an attempt to provide an alternate approach to NASA's plans for the Ares I crew launch vehicle and the Ares V cargo launcher, the later of which is a Saturn 5-class rocket that will carry Altair lunar landers into orbit. The idea is to replace the Ares launchers with a single universal launch system that would be derived from existing shuttle hardware.
You can read about the proposal by clicking HERE. (http://www.launchcomplexmodels.com/Direct/documents/DIRECT_Summary_v2.0.1.pdf)
NASA engineers and mission managers analysed the proposal and determined the the rocket system being offered up was not suitable for envisioned missions and that it would be in the nation's best interest to continue the ongoing Ares I and Ares V development programs. You can read the detailed NASA analysis by clicking HERE (http://www.nasa.gov/pdf/257003main_NASA%20Performance%20Assessment%20of%20(DIRECT%202)%20Compiled.0702.pdf).
William Gerstenmaier, NASA's Associate Administrator for Space Operations, told FLORIDA TODAY last week that the agency intends to "stay the course" with the Ares I and Ares V rockets and would be so advising Congress. He noted that all major Ares 1 procurement contracts had been awarded by the end of last year and that switching focus to another system at this stage would only serve to extend an anticipated five-year gap between the last shuttle flight in 2010 and the first piloted Orion mission in 2015.

http://floridatoday.com/apps/pbcs.dll/section?category=news02

JimMcDade
07-31-2008, 10:48 AM
Will the real rocket scientists please stand up? Well, as we see in this NASA report, the real rocket scientists have stood up and declared DIRECT 2.0 to be pure balderdash.

Isn't it amazing that the enlightened, (inject tenor of sarcasm here) avant-garde DIRECT 2.0 cult still clings to their maniacal convictions?

J.McDonald
09-19-2008, 12:54 PM
Is there a more thorough report available? There are some statements that I don't understand, for example:

"the limited data available in the online DIRECT proposal do not
support the claims of increased safety."- As I understand it, the 'safety' aspect hinges on use of proven SRBs vs. new ones. I'd be interested to see how NASA examined this subject, and how confident they are in their estimation of 5-seg SRB safety.


"Also, analysis shows that the DIRECT proposal would cost more than the Ares family in the near-term": what items on Direct do NASA say will cost more than Ares? How do these outweigh the need for new SRBs, pads, VAB bays, barge, crawlers, crawlerway, etc etc?

"The Jupiter’s Shuttle External Tank (ET)-based core stage in fact would require a major development effort, which in turn would drive a longer schedule when compared to the current Ares approach."- yet so does the Ares-V core. In fact, you would think that the Jupiter core would cost less than the Ares-V core because it has more in common with the ET.

"The Jupiter common core requires new design efforts for the main propulsion system, new thrust structure, new avionics, new forward liquid oxygen tank structure and a new payload shroud, substantial intertank/liquid hydrogen tank redesign and aft Y-ring interfacing and a completely new stack integration effort."- again, all of these things should apply to Ares-V as well. Except, again, you would think that in Jupiter they would cost less, being smaller, more similar to STS, etc.

"In addition, recurring ET manufacturing is costly and labor intensive compared with the lower cost, all friction-stir-welded approach being used on the Ares vehicles."- this is very interesting. I hadn't heard of this. Presumably, the new techniques could be equally well applied to Jupiter, though?

"Also, the Jupiter core stage engine, the RS-68, would be required to be human rated. Though feasible, it would require a significant development effort and an extensive engine test program, again increasing development schedules."- AFAIK The Direct team used OSP data here. Further, Griffin has in the past suggested man-rating of Ares-V; I see no show-stopper here at all.

"Per-flight costs for Orion missions also favor the Ares approach. The Ares I vehicle will have less cost per flight compared with the Jupiter 120 heavy lift counterpart: one five-segment RSRM versus two four-segment boosters and an upper stage with one J-2X versus a core stage with two or three RS-68s."- I was under the impression that costs were nowhere near this simple to calculate. What of fixed costs, or the 'bulk buy' effect? How would these change things?

Thanks,

John

Rick
09-19-2008, 01:35 PM
John, is this the report you are quoting from:

http://www.nasa.gov/pdf/257003main_NASA%20Performance%20Assessment%20of%20(DIRECT%202)%20Compiled.0702.pdf


I do not at the moment have time to read through it. After scanning this, it seems pretty thorough to me.

I believe that this is the only document out there other than the summary that NASA has or will put out there.

J.McDonald
09-19-2008, 03:01 PM
Have had a brief read, it seems pretty clear-cut that J232 would have a significant performance shortfall. Also interesting to read that the Direct team seemed to have missed an engine in their mass estimates (ouch).
Unfortunately, though, there's no more information about the costs etc. So these statements still surprise me. Any takers?