I agree with Doug Cooke, NASA exploration systems mission directorate's deputy director, that the DIRECT concept is not the optimal solution its proponents claim it to be
I made my opposition to DIRECT clear in a reply to a reader's comment on this blog in January
credit: DIRECT
And I still think that DIRECT, on closer examination, would not be able to escape the issues encountered by Constellation; the switch to a five-segment sold rocket booster, the use of at least six RS-68 engines for the core stage and substantial integration, manufacturing and technology development issues with the rest of its lunar architecture
To those of you who have not seen the widening blogosphere coverage of this side issue, NASAWatch started asking NASA if its engineers had examined the DIRECT concept awhile ago. The agency denied it but since NASAWatch obtained this Marshall Space Flight center presentation and Florida Today's space blog located this other pdf document that has appeared on NASA's website server
But I do have my own doubts about Ares I's first-stage and am waiting for NASA to solve its problems
To those of you who have not seen the widening blogosphere coverage of this side issue, NASAWatch started asking NASA if its engineers had examined the DIRECT concept awhile ago. The agency denied it but since NASAWatch obtained this Marshall Space Flight center presentation and Florida Today's space blog located this other pdf document that has appeared on NASA's website server
But I do have my own doubts about Ares I's first-stage and am waiting for NASA to solve its problems
NASA's critique was done against a Jupiter vehicle configuration that was still evolving, and incapable of performing the lunar mission without a propellant transfer in LEO. It was detailed in the AIAA 2007 paper submitted to the Society in September of last year. At that time, we clearly stated that the configuration was a work in progress, and that more changes were coming that would indeed enable a proper lunar ESAS mission. We published the incomplete design “as is” at that time because we were up against a publishing deadline imposed by the AIAA.
True to what we stated, the design has evolved, and now indeed does accomplish the complete ESAS lunar mission, without any propellant transfer of any kind. It is posted on the website for all, including NASA, to see. As of today's date, July 4th, 2008, the Ares-I/V is still incapable of even a minimal lunar mission, still being a minimum of 8 metric tons short of what's required to go thru trans lunar injection. But the 2xJupiter-232 profile not only meets the ESAS minimum, it exceeds it.
The AIAA paper was published in September 2007 and the NASA critique was completed the following month, October 2007. NASA then sat on it for almost 10 months, all the while the Jupiter was evolving – just like we said it would. Then they released their analysis of the house of cards.
When asked, NASA OFFICIALLY claimed that they were doing no analysis of the DIRECT proposal. Then they turn to the other side of their face and publish the non-existent analysis, and analyze a non-existent design.
There are many, many things in NASA's analysis that are very wrong, misleading and completely misstated. I will name just one, and leave the rest for an upcoming response that will be placed, at the very least, on the www.directlauncher.com website.
It is significant that the critique faults the DIRECT architecture for reusing the STS infrastructure, on 2 points.
First, that is specificically what the Congress directed NASA to do; reuse the infrastructure.
Secondly, The Ares architecture completely destroys the STS infrastructure, which means that it will need to be replaced, in its entirety, by all new structure. The latest Ares-V design is so massive that even the Crawlerway will need to be replaced; it cannot handle the weight. That is going to cost the taxpayers hundreds of millions of dollars more that wasn't supposed to spent. In addition, it's next iteration, which is baselined internally, is so tall that it no longer fits inside the VAB. That too will need either MAJOR structural overhaul, or complete replacement. Hundreds of millions to do what the Congress told NASA not to do.
And it still isn't able to put a human crew on the moon.
But the Jupiter-232 launch vehicle, as it exists in design today CAN do the job that the Ares can't. It is even able to do what the Ares will never be able to do; global lunar access with anytime return. It can even abandon the inefficient EOR-LOR architecture and go to an L2 based architecture, which could allow a 85mT lander to settle on the lunar surface. Ares can't even get to the L-point, but Jupiter can not only get there, it can get there with margin to spare.
Hi Chuck, it will be interesting to see how this debate plays out. My gut feeling is that for the global lunar mission to an outpost(s) envisaged by NASA's scientists you and Constellation are both hampered by a politically driven industrial footprint (Congressional footprint) strategy that ignores the conventional planning of mission requirement, payload requirement, transportation requirement, that should have driven vehicle design; that would and should have led to all the STS systems being junked because of the fundamental engineering truth about spaceflight, our technology is so limited everything is optimised to a specific mission and trying to re-purpose that for a new mission is an engineering rehash nightmare, which you are all encountering. Best of luck in fighting it out to a mutual death in the wake of a President Obama space policy review.
Rob.
You might want to take the time to read up on both the proposal and the discussion at the NSF forums to get a better understanding of the issues.
Obviously any LV development project will encounter issues. But there's far less risk and cost involved if you start with a plan that meets your design requirements, and that requires far fewer billions in development and operating costs.
After years of design work, neither Ares V or the even bigger six-engine version that NASA is now planning (Ares VI?) are able to meet Constellation's requirements of 75.1 t of mass to TLI. NASA's Oct 2007 review suggests that the mid-2007 version of Direct coupled with a heavy Boeing-designed EDS will not meet Constellation's requirements. But this NASA review does not consider the current Direct 2.02 proposal, or Direct's lightweight LM-Centuar style EDS.
Direct's performance numbers have been vetted by both NASA insiders using POST (Program to Optimize Simulated Trajectories), and by outside experts in the field using tools like CEPE. You can confirm the numbers yourself using the CEPE payload estimator, if you like.
The most important benefit of Direct besides being able to meet NASA's design requirements is that it might actually get built, unlike the Ares V/VI pipe-dream. NASA doesn't have the budget to operate ISS, Ares I, Ares V/VI, and lunar missions. By only having one set of development and fixed costs shared between the crew launcher and heavy launcher, Direct might just be something that NASA can afford.
Rob hit the nail on the head i.e. the "politically driven industrial footprint (Congressional footprint) strategy".
When Obama gets in all of this will be brought back to zero base and rethought. Same goes if McCain wins. This whole launch food fight has produced a lame official answer and an even lamer counter-answer.
Anyone with half a brain would, as Rob suggests, see that Shuttle stuff - as is - or "derived" - is not the way to go.
"President Obama space policy review"
You just just dropped in creditability as a journalist with that comment.
Also, you can't hide your motives. Your opposition to Direct and agreement with Cooke is a veiled ploy just to keep your NASA sources happy. You are afraid that criticism of the status quo and you will be cut off. Just keep drinking the koolade
If you think I am out to keep NASA happy, you clearly don't read my stuff. I am a journalist, I am nobody's friend.
Unless NASA brass sits down with the DIRECT people and shares their data in a truly collaborative fashion, Spring 2009 shall be a train wreck.
This may very well be true:
Or it may not be true.
That is why the American people and taxpayers need either a 3rd party review OR genuine collaboration and review between Team ESAS and Team DIRECT.
Unless NASA's top brass shares all of the relevant data and does a genuine collaborative review or credible 3rd party review by the end of 2008, Spring 2009 shall be a political bloodbath -- whether it is POTUS John ("freeze & review") McCain or POTUS Barack ("I love robotic exploration") Obama.
As for the shuttle workforce, PORK GREASE simply is the lubricant needed to keep Congress on board. That fact may be appalling but I do not see it changing.
SDV seems like a damn foolish thing to do, but if you are going to do this foolish thing Direct seems like the way to go.
It is not clear to me why NASA needs a "optimal solution" given that NASA doesn't seem to be able to define the problem it is solving very well. The one thing NASA hasn't shown much ability to engineer to is schedule. I would suggest that a flexible launch system that is able to handling changing payload requirements might be better in the long run, even if most of the time the rockets are launching less "optimal" payload manifests.