Author Topic: Do you believe in DIRECT?  (Read 70528 times)

Offline luke strawwalker

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Re: Do you believe in DIRECT?
« Reply #60 on: 01/08/2008 07:43 pm »
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brihath - 8/1/2008  11:43 AM

I voted for number 4.   I'm not in the space industry, but I was responsible for making sure a SAC bomb wing kept its planes flying and on SIOP alert when I was in the AF.  I always had a credo that if it looks like it should fly, it generally should fly.

The DIRECT concept builds on 25+ years of Shuttle experience, so much of the vehicle has been flight proven and it minimizes the design changes from STS, while ARES 1 is a completely different story.  If we want to minimize the manned spaceflight gap, we should go with what we know and minimize the risks, especially in the current budget environment.  It's not really that new, as shuttle derived concepts have been bandied about for years.

My only concern with this answer is that a "peer-reviewed" process could become just another bureaucratic dead end that kills a potentially successful flight program.  It's been done before.

Finally, anything we do regarding the manned spaceflight gap should minimize any reliance we have on Russia.  I know we have developed an excellent record of cooperation, but the political winds can change in a heartbeat, and we will be left out in the cold.  It should definitely NOT be something we plan on doing.

Absolutely true... reminds me of "trust, but verify"...  maybe the modern version should be "cooperate, but have similar capability".   That's why I'd love to see RS-84 finished so we'd have our own kerosene engine for the Atlas V if needed.  We could certainly find plenty of use for it if we had it.  OL JR :)
NO plan IS the plan...

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Offline Lampyridae

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Re: Do you believe in DIRECT?
« Reply #61 on: 01/09/2008 12:18 am »
I voted for no. 4, for a number of reasons. Chief among them are:

1. VSE is almost certainly doomed under the next president. A clean sheet proposal (DIRECT 2.0 or EELV) might just save it.

2. This is only anecdotal evidence, but I have seen that there is plenty of support from engineers and other technical types for DIRECT. Some people are willing to risk their careers for it.

3. As an armchair rocket enthusiast, the DIRECT 2.0 numbers look good to me. Throw in what kraisee has said about the oodles of performance margins, I really can't see why it is not a viable proposal.

4. As mentioned previously, DIRECT 2.0 builds right on the proven STS infrastructure and removes the most problematic element, the orbiter.

Offline veedriver22

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Re: Do you believe in DIRECT?
« Reply #62 on: 01/09/2008 01:34 am »
I would vote for #4 and #6.  Since only one vote is allowed I went for #4.

Offline CFE

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Re: Do you believe in DIRECT?
« Reply #63 on: 01/09/2008 03:03 am »
I picked option 3 because of the old adage "no war plan ever survives contact with the enemy."  Things always look easier when you start with the paper proposals and don't reveal all of their challenges until you start bending metal.  The same is true for ESAS, which has changed significantly since Summer 2005.

While DIRECT appears to be pretty straightforward, I can foresee problems arising in manufacturing and test.  No showstoppers, mind you, but things that would delay it from being "safe, simple, soon."
"Black Zones" never stopped NASA from flying the shuttle.

Offline vt_hokie

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RE: Do you believe in DIRECT?
« Reply #64 on: 01/09/2008 03:30 am »
NASA never seems to actually complete a program or deliver all that is promised.  So, I see Ares V going the way of the AMS, ISS hab module, propulsion module, CRV, etc.  I've always thought that with the current approach, we'll get Ares I launching a bare bones Orion with minimal LEO capability, and that's about it.  (Of course, now it looks like Ares I might not even work at all.)  I think it would be wise to get as much capability up front as possible, and not count on future enhancements down the road.

Offline John Duncan

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Re: Do you believe in DIRECT?
« Reply #65 on: 01/09/2008 01:31 pm »
Much depends on who gets the POTUS seat in 09.  Programs from previous administrations tend to be poisonous to new ones.  Whoever gets in will most likely take a step back from VSE.  I just hope that there's a little political pressure from the space contractor constituents to keep *some* kind of a program running.  DIRECT would be a good choice.

I'm just fearfull that exploration will be pushed aside for the numerous new government freebies that are likely to appear no matter who gets control.

Offline William Barton

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Re: Do you believe in DIRECT?
« Reply #66 on: 01/09/2008 02:49 pm »
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John Duncan - 9/1/2008  9:31 AM

Much depends on who gets the POTUS seat in 09.  Programs from previous administrations tend to be poisonous to new ones.  Whoever gets in will most likely take a step back from VSE.  I just hope that there's a little political pressure from the space contractor constituents to keep *some* kind of a program running.  DIRECT would be a good choice.

I'm just fearfull that exploration will be pushed aside for the numerous new government freebies that are likely to appear no matter who gets control.

That's too much of an oversimplification. What happens is new administrations tend to put their own stamp on things. Kennedy didn't cancel Mercury/Gemini, but routed everything into MOL and Apollo. Nixon canceled MOL, but only finished off Apollo once Mars was off the table and STS was chosen. STS wasn't cancelled by Ford, Carter, Reagan, Bush I, or Clinton (I?). Bush II has scheduled STS for the axe to make way for Constellation. ISS may not be Reagan's Space Station Freedom, but it's still a space station, and not cancelled by Clinton.

What happens to VSE (and COTS) is going to vary by candidate, but I think once they get into office, they're going to have to rethink whatever vague plan they may have now. Even Obama is going to have to realize that the only way to get an education budget out of NASA is by cancelling the entire US space program. It probably hasn't occured to him that cancelling VSE and continuing STS/ISS isn't going to save a penny. Of the viable candidates, I think McCain is most likely to continue ESAS as-is. Clinton might put her own stamp on VSE by switching to DIRECT if she could somehow become aware of it. The big danger is, she'll decide to keep ISS running until 2030.

Offline Kaputnik

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Re: Do you believe in DIRECT?
« Reply #67 on: 01/09/2008 02:56 pm »
I was going to vote no.4 but settled on no.3 out of a sense of general pessimism. I believe that the DIRECT team have addressed every issue that they can think of, but I can't help thinking that there will remain as yet unknown issues to address if DIRECT was to be developed- and that these would be essentially political and economic, not technical.
"I don't care what anything was DESIGNED to do, I care about what it CAN do"- Gene Kranz

Offline A_M_Swallow

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Re: Do you believe in DIRECT?
« Reply #68 on: 01/09/2008 05:03 pm »
Run any issues through this forum and see if anyone can suggest solutions.

Offline Norm Hartnett

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RE: Do you believe in DIRECT?
« Reply #69 on: 01/09/2008 07:04 pm »
I voted for four but if it was multiple choice I’d have done 4, 5, and 6.  :laugh:

I fear the Constellation is going to prove to be a dud like so many of NASA’s recent manned space flight efforts of the last few decades and I believe that if it is that it will take ESAS/VSE with it. While I agree with Pad-Rat’s points on the ESAS I disagree with his solution, a space power system. The American public and I have been hearing about this since the fifties and there is no real broad interest or commercial viability in the concept. There maybe eventually but not now nor is there any real broad interest in another moon program. Maintaining four men in a hut at the south pole of the moon at six billion dollars plus annually is not going to be sustainable, like Apollo it will eventually be canceled.

There is a space objective that might capture the interest of the American people that NASA is neglecting though, something that has been the subject of several movies and many programs on the Science Channel and Discovery. Something that Congress has repeatedly asked NASA to look into and that certainly meets Pad-Rat’s criteria of “genuine relevance to the American taxpayer's everyday life” at least perceptually. In fact Representative Rohrabacher recently introduced HR4917 http://thomas.loc.gov/cgi-bin/bdquery/z?d110:h.r.04917: to get NASA moving on this subject (without funding of course).

I am speaking of NEO detection, interception, and defense. A major manned and unmanned program from NASA for this purpose would, I believe, galvanize support from both the public and the politicians. The spin offs of such a program are very positive; much better international perception of our goals in space, plays well with the Earth Firsters, offers more opportunity for commercial/international participation, and, to return to the topic of this thread, DIRECT would be an ideal LV for this purpose.
“You can’t take a traditional approach and expect anything but the traditional results, which has been broken budgets and not fielding any flight hardware.” Mike Gold - Apollo, STS, CxP; those that don't learn from history are condemned to repeat it: SLS.

Offline clongton

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RE: Do you believe in DIRECT?
« Reply #70 on: 01/09/2008 08:09 pm »
To all those who have either selected or are considering selecting option 3 (If accepted the DIRECT would require major overhaul), would you mind telling us what the things are that you believe would be so affected? That will provide us with the opportunity to take a look at them and then provide you with a considered response. Perhaps we have overlooked something. If so, we would certainly like to know about that.
Thanks
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline CFE

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RE: Do you believe in DIRECT?
« Reply #71 on: 01/10/2008 01:21 am »
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clongton - 9/1/2008  2:09 PM

To all those who have either selected or are considering selecting option 3 (If accepted the DIRECT would require major overhaul), would you mind telling us what the things are that you believe would be so affected? That will provide us with the opportunity to take a look at them and then provide you with a considered response. Perhaps we have overlooked something. If so, we would certainly like to know about that.
Thanks

There are no issues I know of surrounding DIRECT, but there's a general fear on my part that there's something I'm missing.  I think of all the "off the shelf" solutions that have been proposed in the aerospace industry and how much they have changed between initial and final implementations.  I think of all the work that was required to adapt the F-86 Sabre into the carrier-based Fury, or the required work to make the A-7 out of the F-8.  In the end, you're left with a system that's quite different from the one you started with.

In terms of changes to DIRECT, I tend to favor the heavy-lift configuration (244) that has 4x RS-68's on the first stage and a 10m, 4x J-2X upper stage (similar in size and performance to the S-II.)  I also think that the upgraded RS-68's (A and B models) should be baselined as soon as practical.
"Black Zones" never stopped NASA from flying the shuttle.

Offline PaulL

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RE: Do you believe in DIRECT?
« Reply #72 on: 01/10/2008 01:51 am »
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clongton - 9/1/2008  3:09 PM

To all those who have either selected or are considering selecting option 3 (If accepted the DIRECT would require major overhaul), would you mind telling us what the things are that you believe would be so affected? That will provide us with the opportunity to take a look at them and then provide you with a considered response. Perhaps we have overlooked something. If so, we would certainly like to know about that.
Thanks

The reason I choose option 3 is not that the Direct rockets are bad, but rather the proposed use of them does not match the current NASA philosophy. There is no way NASA will include propellant refuelling/transfer in space on its reference mission to the moon. Also, NASA wants to be able to send as large as possible unmanned payloads to the moon.   On that point, the current J-232 rocket payload capacity is probably below what NASA wants.

If NASA were to switch from ARES to Direct, I would see them transforming the Direct plan to match the Ares I/V concept: Ares I being replaced by the J-120 which is simpler/safer than the J-232 for manned flights and boosting the J-232 payload capacity as much as possible (with 106% RS-68 and J-2X engines for example).  They could even possibly upgrade the J-232 to a J-242 in order to gain an extra 6-7 mT of LEO payload.  A J-120/J-242 lunar mission using upgraded engines should be able to surpass the payload capacity of the Ares I/V moon mission.

PaulL

Offline Yegor

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Re: Do you believe in DIRECT?
« Reply #73 on: 01/10/2008 04:37 am »
Wow! Overwhelming support for DIRECT! 99 Votes - [72.79%]


Offline kraisee

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RE: Do you believe in DIRECT?
« Reply #74 on: 01/10/2008 09:28 am »
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PaulL - 9/1/2008  9:51 PM

Quote
clongton - 9/1/2008  3:09 PM

To all those who have either selected or are considering selecting option 3 (If accepted the DIRECT would require major overhaul), would you mind telling us what the things are that you believe would be so affected? That will provide us with the opportunity to take a look at them and then provide you with a considered response. Perhaps we have overlooked something. If so, we would certainly like to know about that.
Thanks

The reason I choose option 3 is not that the Direct rockets are bad, but rather the proposed use of them does not match the current NASA philosophy. There is no way NASA will include propellant refuelling/transfer in space on its reference mission to the moon. Also, NASA wants to be able to send as large as possible unmanned payloads to the moon.   On that point, the current J-232 rocket payload capacity is probably below what NASA wants.

If NASA were to switch from ARES to Direct, I would see them transforming the Direct plan to match the Ares I/V concept: Ares I being replaced by the J-120 which is simpler/safer than the J-232 for manned flights and boosting the J-232 payload capacity as much as possible (with 106% RS-68 and J-2X engines for example).  They could even possibly upgrade the J-232 to a J-242 in order to gain an extra 6-7 mT of LEO payload.  A J-120/J-242 lunar mission using upgraded engines should be able to surpass the payload capacity of the Ares I/V moon mission.

PaulL

Just to confirm that while the AIAA paper strongly recommends a propellant depot architecture, with the performance of two Jupiter-232's, we can still easily out-perform Ares-I/V even without any propellant transfer technology at all.   While Ares can not close it's lunar performance targets at all (13mT shortfall currently), 2 Jupiter-232's can close them correctly - with all our margins - both NASA's regular ones, and our own arbitrary ones included.

We went for developing PD at the start simply because it would give NASA so many advantages that its quite amazing.

I thought you (and perhaps others) would like to be aware.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline JIS

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RE: Do you believe in DIRECT?
« Reply #75 on: 01/10/2008 09:36 am »
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kraisee - 7/1/2008  8:29 AM

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JIS - 7/1/2008  2:16 AM

All I wanted to hear is how you get those numbers and if you compared them with other systems which actually went through detailed analysis. ESAS numbers were proved to be quite optimistic taking some estimated weight and applying just overall margin.


Quote
...

Try to look at Jupiter elements weight like core, fairing and EDS and find whether they are comparable with elements from operational launchers or launchers which went at least through some basic NASA analysis. I tried that and wasn't convinced.
I'm citing what I was told by one Direct proponent: "You don't need to be genius to do that."
Until then I simply can't BELIEVE your numbers and have to leave this thread.

Without our arbitrary 10% structures margin, but still including the full GR&A Weight Growth Allowance (WGA), our Core Stage would actually mass 64,412kg, not 69,369kg as presented in the AIAA paper.  

....

At this point, I would refer the gentle reader to the NLS-1 papers I mentioned previously.    Being a similar configuration, but powered by three SSME-class engines, and without a large Upper Stage, it's Core Stage would have massed 54,621kg (including 1.4 factor, very similar GR&A's and standard WGA) - some 15 tons lighter than Jupiter's Core, yet still based on LWT, not SLWT.   Bringing in much of SLWT mass savings to NLS to bring the two "as manufactured" systems into technological comparison, Jupiter's Core is specified to mass about 18mT more than the NLS Core would have.   Again, I would like to find ANYONE who doesn't think this is sufficient additional "bracing" (considering most of the strength is derived from the pressurization of the tanks, not the actual structure itself) to support the extra weight above?


OK. I tried again to compare available data for cores using two SRBs attached at intertank. I choose to compare cores as there are multiple studies which actually did some analysis instead of just applying some factors.  

Jupiter
Usable props: 1595 klbs
engines: 3 x RS-68
total thrust: 2253 klbsf
dry weight: 153 klbs (69mt)

NLS
Usable props: 1693 klbs
engines: 4 x STME
total thrust: 2600 klbsf
dry weight: 179 klbs

ATK proposal of CaLV
Usable props: 1588 klbs
engines: 4 x RS68B
total thrust: 3136 klbsf
dry weight: 221 klbs

ESAS CaLV
Usable props: 2215 klbs
engines: 5 x SSME
total thrust: 2345 klbsf
dry weight: 195 klbs

Ares V
Usable props: 3078 klbs
engines: 5 x RS68B
total thrust: 3920 klbsf
dry weight: 301 klbs

It doesn't need much effort to find that Jupiter core could be "reasonably" right. Unfortunately I can't find any numbers for cores with lower thrust and the same amount of propellants (there are such cores in ESAS for example).
However, the core is not what I was particularly criticizing as its properties are well known from many studies and ET is actually flying today.
Also the core, fairing, interstage and SRBs weight is order of magnitude less important for payload than US structures, payload adaptors etc. which are more difficult to analyze.  
I think that similar comparison for other DIRECT elements can be quite useful for all non believers to help them to believe. Alternatively, you can put forward some preliminary load and stress analysis performed on Jupiter.  
 
Quote
Frankly, I'm sick-to-the-back-teeth of people whining about things they "can't believe", people who seem to have very little grasp of the realities and who very often "conveniently" forget things which we've told them specifically about over and over again.

It could be your fault too. There were many claims made by you which have proven to be misleading or false. I appreciate that there might be many other claims being 100% accurate but I can’t simply believe in everything I’m being told.    

Quote
If you have serious technical concerns or questions, bring them, in fact we welcome them because we're always on the hunt for anything we might have missed.   But this *constant* negative "can't work" attitude is mind-numbingly tedious and excruciatingly annoying.   Please quit it.
Ross.

The above example with cores was very easy and simple one. After all it’s just payload capability which can be affected. I have no doubts that Jupiter can be designed, built and fly.
More serious are doubts about mission architecture, schedule and costs. Especially when they significantly differ from NASA numbers.
It is quite surprising to me that some people are questioning cost estimates but are happy to support DIRECT as the whole.
'Old age and treachery will overcome youth and skill' - Old Greek experience

Offline kraisee

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RE: Do you believe in DIRECT?
« Reply #76 on: 01/10/2008 09:39 am »
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CFE - 9/1/2008  9:21 PM
I also think that the upgraded RS-68's (A and B models) should be baselined as soon as practical.

We have already worked out all the performance combinations for the various engine combinations.   We know what they can do, and how they would affect the performance of the Lunar architecture.   But those engines don't yet exist.   That means they are still subject to possible cancellation.   One theoretical scenario might be that the 106% RS-68 development program USAF is paying for could be canceled if ULA were to down-select to Atlas in two years time.

We simply don't want to find ourselves in a position of promising 'x' performance, based on a higher performance engine, but then find we are denied the additional performance and have to bring our promised performance numbers *down* later.

We would far rather promise the smaller performance based on existing performance systems, and then be able to increase our performance numbers as newer, better, tech becomes available.

It means the additional performance is never an essential component in the path to success.   Additional performance becomes simply an extra benefit which we can make great use of later.

I think the 106% RS-68 will only be guaranteed around about the time of the very first test flight (somewhere around 2010 or so IIRC).   Until then, we consider it a valuable egg still awaiting to hatch into an even more valuable chicken :)

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline JIS

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Re: Do you believe in DIRECT?
« Reply #77 on: 01/10/2008 09:59 am »
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JIS - 7/1/2008  12:56 PM

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The question is not useful so I decline to vote or add voting options.

It's for the purpose to find how many naysayers and supporters are visiting this forum and how many of them are willing to admit that.
If you don't vote I think you could be just undecided or didn't read that study. Please, add appropriate option and vote for it.

I think that it is unlikely that the result of poll is going to change significantly. About
80% active visitors strongly suport DIRECT and believe this is the right direction.
There were few people rising questions but there is generally strong support. Even I have admited that there is no technical objection to stop Jupiter working. But Direct is not only about launch vehicles.

The major finding for myself is the confirmation that many people oposing Direct do not want to take part in the discussion. I can understand that.
'Old age and treachery will overcome youth and skill' - Old Greek experience

Offline clongton

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Re: Do you believe in DIRECT?
« Reply #78 on: 01/10/2008 11:32 am »
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JIS - 10/1/2008  5:59 AM

The major finding for myself is the confirmation that many people opposing Direct do not want to take part in the discussion. I can understand that.
JIS;
Not to put too fine a point on this, but how can you know that?
You appear to be basing your statement on the fact that not many people have voiced opposition to DIRECT. It is equally possible that there simply are *not* many people who oppose it as well. You are citing the fact that not many people voted in opposition of DIRECT as *confirmation* that a large number of people do not wish to vote. The fundamental rule of a poll is you don't get to count votes that are not cast, nor are you allowed to draw conclusions from un-cast votes, because fundamentally you have absolutely no idea how many, or even *IF* there are any un-cast votes.

Your "confirmation" is invalid.
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline kraisee

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Re: Do you believe in DIRECT?
« Reply #79 on: 01/10/2008 12:00 pm »
Chuck,
I think everybody on the board knows what's really going on here.   They aren't stupid.   I think this 'poll' is a total waste of everybody's time and I really don't think we should continue to 'entertain' this rubbish any further.

If JIS is dis-satisfied that's his call.   He tried to push the issue, we pushed back.   Feeling hurt, he tried to call for what is essentially a "vote of no confidence" - an effort which didn't work and if anything actually seems to have helped solidify the competing position.

At this point I'm pretty sure every reader here knows everyone's motives and has made their own judgments and 'spin' tactics like those you responded to aren't convincing anyone.

JIS clearly looks like he will never be satisfied with our efforts, so I just don't think there is any point in engaging in further discussion with him at this point.   His comments and actions have clearly placed him as an agitator and opponent to DIRECT, and clarified that his comments and questions are not meant to be constructive - merely destructive.

With purely negative motives behind his actions there is zero benefit to us from engaging him any more.   It is time to simply try to ignore him in reference to anything DIRECT-related from this point onwards.

Should he persist, or attempt to pursue a vendetta in the future for being embarrassed by being called-out for his actions, I suggest we rely upon the forums moderators and managers keeping things under control.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

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