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#200 by kraisee on 02 May, 2006 06:38
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Kayla - 1/5/2006 10:11 PM
...you go on to try and suggest that shuttle is cheaper than EELV.
Pardon?
I have said no such thing, ever.
If you are referring to my big post the other day where I broke down the broad costs for EELV, Shuttle and Ares launchers, please go back and re-check the figures there again. You will see that Shuttle is FAR more expensive than EELV for $/kg to LEO, by about 4 times. There again, the Shuttle-derived Ares vehicles NASA is building will ultimately be about two to three times more cost effective than the EELV's.
Shuttle, to me, is a horrendous waste of current budget resources, has a pathetic performance and requires an extortionate amount of time to process - all primarily because of the reusable and overly complicated Orbiter.
I have been firmly of the opinion that it should be retired immediately, although I would consider flying one more service mission to Hubble.
I have also previously stated that if the current 1 in every 87 flight failure rate borne-out so far for Shuttle continues, we have less than a 1 in 5 chance of getting through the 17 remaining flights planned without another disaster, and I do not believe NASA should be risking the entire future of the VSE by risking flying the Shuttle so many more times when CaLV could be used far more cost effectvely instead.
Consistently for the last year or more, I have stated that the sooner we retire Shuttle, the sooner we can start the transition into the new program. It is my belief that every year we continue to waste flying Shuttle missions in order to partially complete the ISS, we put off the return to the Moon by another year and waste the opportunity to ultimately finish the full ISS which we could do with CaLV.
Make no mistake, I will continue to say so at any given opportunity.
Ross. -
#201 by Tap-Sa on 02 May, 2006 07:05
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I'm serious, the decision has already been made and unless there is such a massive critical error that it'll scuttle the whole plan, the decision has been made and we all need to get on the same page, or get left behind. The train is already moving dude...
I'll continue to believe that NASA has control of the money for the STS program to do with whatever it wishes, and that NASA has already made its choices and is now actively persuing them.
Everything else is just wishful thinking.
Btw (1 - 1/87)17 yields 0.82 probability that remaining flights happen without disasters.QuoteThere again, the Shuttle-derived Ares vehicles NASA is building will ultimately be about two to three times more cost effective than the EELV's.
How come you bash the shuttle, vehicle NASA built, so freely and yet adamantly believe that another vehicle NASA insists on building will be a heaven sent delivering all promises made? Rather ... dualist thinking. -
#202 by kraisee on 02 May, 2006 08:47
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Tap-Sa - 2/5/2006 3:05 AM
Btw (1 - 1/87)17 yields 0.82 probability that remaining flights happen without disasters.
Yeah, I said 87 didn't I? Meant Shuttle's proven record of 2/114 (1:57) failure rate, which results in 1 in 2.9 chance of losing another orbiter in the next 17 flights.
Mind you, even with the 1/87 rate that means 82% probability of success = 18% probability of failure. That's still close to the 1 in 5 chance I mentioned.
That's the problem with statistics, you can make them say almost anything you want. Although both of these result are in the 1 in 4 (+/-1) ballpark, which is still pretty crappy odds for us to be risking the future of the exploration program on IMHO.QuoteHow come you bash the shuttle, vehicle NASA built, so freely and yet adamantly believe that another vehicle NASA insists on building will be a heaven sent delivering all promises made? Rather ... dualist thinking.
Its not dualist thinking, its contextual thinking.
The big difference is that NASA, this time, is simply not trying to push the boundaries of what's possible as was done with Shuttle. Shuttle was an awful lot of new concepts brought together - reusablity, wings, new materials, side-mounted payloads, crew & payload together, payload return capability, runway landings etc etc. It was also an unheard of degree of complexity brought together too, and yet it was a system which was never designed to have a crew escape system.
While some elements are common, it is the conceptual design of the new launchers which is so much simpler than Shuttle. The designs return to the very basics of rocketry, and are fundamentally very simple from the inception of the program. All in a drive to get the safest possible vehicle we can make (I'll qualify that, of course, by mentioning they are still constrained by the available resources at this time; budget, engines, facilities, workforce, political will etc).
CLV, fundamentally is one of the simplest possible designs - A single solid motor for the first stage, with a single engine on a liquid upper stage and the crew module & full escape system placed on top. That's basically all there is to it. Nobody has made a conceptually simpler manned rocket since Mercury/Gemini!
CaLV, fundamentally is just a vertically stacked two-stage rocket, with solid booster strapons and the payload is placed on top. That's a pretty common configuration for a rocket anywhere in the world, and is a very well understood concept which has been well-proven over and over again for 40-odd years now. The only unusual factor is the large size and thus the capacity of the vehicle.
Although Shuttle is a quarter century old now, it is still a radically unusual configuration for a rocket. The Russians tried the same basic concept about 20 years ago, flew it once and then promtly retired it because it just wasn't cost effective and simple (that means safe) as their other systems. As it stands, America didn't accept that lesson until 2003, yet will still continue to fly it for another four years.
The configuration of the Shuttle launch vehicle is a complicated one. That complexity has meant that after 25 years of use, it still is not as well-proven as we'd like it to be. It also has some pretty serious, and now quite obvious, flaws in the design too. Columbia graphically demonstrated one of the Shuttle's unique flaws, a flaw which no regular vertical rocket design would ever have suffered from. The current fleet were all re-classified to experimental craft again, specifically because the configuration is no longer considered to be as safe as we would wish.
Yet individual elements of the Shuttle system actually work very well. For example, the SRB's now have 226 successful manned launches, and over 35 successful test firings under their belts - which is better than any other engine in America's arsenal. The SSME's have 337 successful manned launches under their belts, with just two premature shutdowns in the flight history, both caused by faulty instrumentation, not mechanical failure.
The Full Shuttle Stack actually places 115 tons of material into space every time it launches to the ISS, but the final useful payload, because of the mass of the Orbiter vehicle itself, is only 16 tons, or just 14% of the stuff which was placed up there. The same basic hardware, if just assembled in a different configuration, could actually put about 95+ tons of truly useful payload up on every flight. An evolved configuration of that same basic hardware is going to ultimately be able to put nearly 150 tons of useful stuff up there in the form of the CaLV.
These good elements just do not work so well together when "combined" into the horrifically complicated STS system we continue flying today though. For example, if there were no Orbiters riding on the side of the ET, the tank foam shedding issue becomes completely irrelevant. Similarly, if there had been no external tank next to the SRB on the ill-fated STS-51L's flight, the burn-through the SRB suffered could not have caused the strut to fail, which caused the tank to rupture. Analysis shows that if an even worse burn-through were to occur on a CLV, it would not put the crew, nor the mission, at critical risk. The SRB's are actually fixed these days, so the CaLV can take that particular risk, also it is not so dangerous because it is not planned to actually launch with crew aboard it, just lots and lots of payload.
The basic elements of the Shuttle, if simply put together in a new way, can be made into vehicles which are far, far safer than Shuttle.
Ross. -
#203 by josh_simonson on 02 May, 2006 18:38
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As I understand it, NASA is contractually obligated to pay for the shuttle through 2010 and dropping the program now doesn't save much money. If NASA defaulted on it's contracts, the contractors would demand more money up front for future projects because there would be a risk of default.
It's like trying to get ridd of car payments by throwing away the car. Doesn't work that way. -
#204 by kraisee on 02 May, 2006 19:48
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josh_simonson - 2/5/2006 2:38 PM
As I understand it, NASA is contractually obligated to pay for the shuttle through 2010 and dropping the program now doesn't save much money. If NASA defaulted on it's contracts, the contractors would demand more money up front for future projects because there would be a risk of default.
It's like trying to get ridd of car payments by throwing away the car. Doesn't work that way.
From the stuff that I've heard (nothing official) all the contractors seem quite willing to get into the new program whenever NASA wants to. Fundamentally we're talking about LM and Boeing (including their 90% co-ownership of USA) taking the lion's share of current Shuttle budgets, and they both know that they're going to be doing the bulk of the new program too, so they're not worried about losing money from this transition and there would be no significant loss to NASA to just re-negotiate the contracts whenever they want. For example, if the current flight manifest were to be borne out, and the last flight of Shuttle actually happenend in 2009, the Shuttle program would be decommissioned then and the contracts would transition into the Exploration stuff there instead of 2010.
To continue your analogy, when you trade in a car for a newer one, you can usually transfer your payments to that new vehicle too.
Its not the contracts which are the big hold-up, its the the fact that the US government must complete its political obligations for the international partner nations in the ISS project, and the subsequent decision to do all the construction using the Shuttle which is preventing anything moving fast on the VSE yet.
Ross. -
#205 by Jim on 02 May, 2006 23:32
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USA is not guaranteed any work. The hardware providers are going to process their own hardware, not USA.
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#206 by Kayla on 02 May, 2006 23:44
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kraisee - 2/5/2006 3:47 AM
CLV, fundamentally is one of the simplest possible designs - A single solid motor for the first stage, with a single engine on a liquid upper stage and the crew module & full escape system placed on top. That's basically all there is to it. Nobody has made a conceptually simpler manned rocket since Mercury/Gemini!
Ross.
If it is so simple why does it take well over $7B and 8 years to get there?
EELV's were accomplished in a fraction of that time for a fraction of the cost!
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#207 by Kayla on 02 May, 2006 23:52
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kraisee - 2/5/2006 3:47 AM
Yet individual elements of the Shuttle system actually work very well. For example, the SRB's now have 226 successful manned launches, and over 35 successful test firings under their belts - which is better than any other engine in America's arsenal. The SSME's have 337 successful manned launches under their belts, with just two premature shutdowns in the flight history, both caused by faulty instrumentation, not mechanical failure.
.
You are slightly forgetting the RL10 with 400 or so flights and thousands of ground firings
And ATK's Gem solids on the Delta 2 with something like 800 firings and 1 failure.
There are other engines that have even more experience than the ATK SRB'sQuoteThese good elements just do not work so well together when "combined" into the horrifically complicated STS system we continue flying today though. For example, if there were no Orbiters riding on the side of the ET, the tank foam shedding issue becomes completely irrelevant. Similarly, if there had been no external tank next to the SRB on the ill-fated STS-51L's flight, the burn-through the SRB suffered could not have caused the strut to fail, which caused the tank to rupture. Analysis shows that if an even worse burn-through were to occur on a CLV, it would not put the crew, nor the mission, at critical risk. The SRB's are actually fixed these days, so the CaLV can take that particular risk, also it is not so dangerous because it is not planned to actually launch with crew aboard it, just lots and lots of payload.
The basic elements of the Shuttle, if simply put together in a new way, can be made into vehicles which are far, far safer than Shuttle.
Ross.
I love it when folks say just simply put to gether the various parts of a rocket and Wala, you have an even better rocket. This integration is what makes a Rocket Scientist!!! This is the hard, expensive and risky part. How do you get it all to work together. -
#208 by kraisee on 03 May, 2006 04:52
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Kayla - 2/5/2006 7:52 PM
Quotekraisee - 2/5/2006 3:47 AM
Yet individual elements of the Shuttle system actually work very well. For example, the SRB's now have 226 successful manned launches, and over 35 successful test firings under their belts - which is better than any other engine in America's arsenal. The SSME's have 337 successful manned launches under their belts, with just two premature shutdowns in the flight history, both caused by faulty instrumentation, not mechanical failure.
.
You are slightly forgetting the RL10 with 400 or so flights and thousands of ground firings
And ATK's Gem solids on the Delta 2 with something like 800 firings and 1 failure.
There are other engines that have even more experience than the ATK SRB's
As susual, you jump to conclusions without actually reading my comments fully. Please note the words I have had to highlight in my quoted comments above.
Unless RL-10 or GEM solids have been flying some black-ops manned craft from Area 51 that we haven't heard of, they have not got any MANNED use under their belts at all, and in fact are not even rated for any manned use at all (RL-10 probably will be for the new program though).QuoteQuoteThese good elements just do not work so well together when "combined" into the horrifically complicated STS system we continue flying today though. For example, if there were no Orbiters riding on the side of the ET, the tank foam shedding issue becomes completely irrelevant. Similarly, if there had been no external tank next to the SRB on the ill-fated STS-51L's flight, the burn-through the SRB suffered could not have caused the strut to fail, which caused the tank to rupture. Analysis shows that if an even worse burn-through were to occur on a CLV, it would not put the crew, nor the mission, at critical risk. The SRB's are actually fixed these days, so the CaLV can take that particular risk, also it is not so dangerous because it is not planned to actually launch with crew aboard it, just lots and lots of payload.
The basic elements of the Shuttle, if simply put together in a new way, can be made into vehicles which are far, far safer than Shuttle.
Ross.
I love it when folks say just simply put to gether the various parts of a rocket and Wala, you have an even better rocket. This integration is what makes a Rocket Scientist!!! This is the hard, expensive and risky part. How do you get it all to work together.
Kayla, I've told you once that sinking to that level is unworthy of you. You're smart, you're well informed, you have no reason to make comments at that level.
It cheapens the quality of real discussions to the point that the whole forum loses integrity, and I don't believe that's something any of us wish to have happen here. The quality of discussions here has been generally very high. Lets not actively do anything to lower it, okay? If you have a useful comment instead of just sniping for the sakes of sniping, then please make it. Sniping is common on so many of the other boards, but unless I'm mistaken it isn't welcome here.
Pedantry and word games just to gain one-upmanship to make you feel better, is a game I don't wish any part of. It reflects badly on the writer, and frankly it just fraks me off. I've tried to give you signs that it isn't welcome, even a few gentle jabs back in your own direction to try to get you to stop, but you seem to have ignored all my attempts thus far: So I'm going to say it now as bluntly as I can - please quit it. I came to this group to try to get away from all the bitchy ones out there, and I don't want NSF to fall into the same bad habits.
You know precisely what I meant, yet you decided to take a cheap shot.
For the record: I repeated four or five times in that single post that I was talking on a "conceptual" level, not the level of "execution". Tap Sa basically asked me why I had a problem with Shuttle, but not with the SDLV's. My prime difference between Shuttle and it's SDLV brethren is very specifically the fundamental "conceptual design" behind the vehicles. I didn't think anyone could possibly miss the fact that "conceptual" discussions is a completely different thing to the "execution" level. The execution level is frankly irrelevant to the points I'm trying to make in my discussion with Tap Sa.
In a purely "conceptual" context like I was using, it is a relatively "simple" change to put the payload on top of a rocket instead of hanging on the side. I would certainly agree, in a different discussion, that the physical execution of this change would indeed be a radical engineering project, but it still remains a "simple" change at the purely conceptual level I was describing.
I will go on and detail all the conceptual changes which I think make CLV and CaLV significantly better concepts than Shuttle if Tap Sa or someone else would really like, heck maybe even the "execution" aspects if people want to get into that depth, but I'll only deem to reply to logical discussions, reasoned arguments and pleasantly presented questions on this subject from now on.
Ross. -
#209 by yinzer on 03 May, 2006 07:20
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kraisee - 2/5/2006 9:52 PM
QuoteKayla - 2/5/2006 7:52 PM
You are slightly forgetting the RL10 with 400 or so flights and thousands of ground firings
And ATK's Gem solids on the Delta 2 with something like 800 firings and 1 failure.
There are other engines that have even more experience than the ATK SRB's
As susual, you jump to conclusions without actually reading my comments fully. Please note the words I have had to highlight in my quoted comments above.
Unless RL-10 or GEM solids have been flying some black-ops manned craft from Area 51 that we haven't heard of, they have not got any MANNED use under their belts at all, and in fact are not even rated for any manned use at all (RL-10 probably will be for the new program though).
Look at the table on page 472 of the ESAS full report. An upper stage with 2 RL-10s is predicted to be more reliable than one with one J-2S. An upper stage with four RL-10s is vastly more reliable. "Man rating" is supposed to provide increased reliability; if you already have much higher reliability than engines that are considered acceptable for manned use, what's gained by going through the process? -
#210 by kraisee on 03 May, 2006 08:32
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Kayla - 2/5/2006 7:44 PM
If it is so simple why does it take well over $7B and 8 years to get there? EELV's were accomplished in a fraction of that time for a fraction of the cost!
The "Moorman Study" was presented by the DOD to Congress in April 1994. It was followed immediately by the official EELV program proposal being presented to the White House by the US Air Force on 17th May 1994. President Clinton signed the National Space Transportation Policy on 5th August 1995, and the USAF immediately created the official EELV Program Office within just 4 days of that authorisation! After conducting a few months of initial work, an RFP was distributed to select companies in May of 1995. A downselect from 4 bidders to just LM & Boeing as the final contractors occurred in December 1996, and the further downselect due around 1998 was never implemented, leaving the two contractors to continue competing all the way into production.
The very first maiden test flight of an Atlas-V EELV didn't take place until 21st August 2002 - which was 8 years and 12 days after the official creation of the EELV program. The first Delta-IV EELV flew just two months after the Atlas.
As for costs, its simple: They were never man-rated. You want to see costs rise? Just man rate them. Historically, the guideline I've heard is that adding in the human requirement triples or quadruples the development price of any given launcher, and roughly doubles the cost of every flight.
Ross. -
#211 by Sergi Manstov on 03 May, 2006 08:45
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Can users use civil talk when answering people's posts. We will remove those that cannot or lock threads. Zero tolerance.
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#212 by kraisee on 03 May, 2006 08:56
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yinzer - 3/5/2006 3:20 AM
Look at the table on page 472 of the ESAS full report. An upper stage with 2 RL-10s is predicted to be more reliable than one with one J-2S. An upper stage with four RL-10s is vastly more reliable. "Man rating" is supposed to provide increased reliability; if you already have much higher reliability than engines that are considered acceptable for manned use, what's gained by going through the process?
There are a lot of different factors to consider when man-rating a vehicle. The process involves exhaustive testing, re-testing and analysis over and over again into more things than are checked for unmanned vehicles. Things like determining how an engine might fail is not so important for unmanned payloads because whether it never fires or blows up still normally results in a loss of the payload & the mission. On a manned craft you obviously want to make sure that your engines don't fail at all, but because that's impossible to do realistically, you have to assume failures will happen and make sure they are not going to be life threteneing when they do go wrong. They have to put a lot of work in to make sure that when it ever does fail, it shouldn't fail by blowing up the entire craft as it dies. That may require redesigning some parts to make them stronger, and more cble to survive critical failure modes, or it may just assess that a certain software controlled sequence would be able to shut the engine down safely in case of a detectable problem. Many of these sorts of issues are done on unmanned rockets too, just not as exhaustively and thoroughly as for manned craft.
Also, more generically, there will be an extensive analysis into trying to predict every single type of failure every single element of a vehicle can suffer from and if one failure here will have any effect on another element anywhere else in the vehicle. If you know how a piece can go wrong, you may be able to mitigate the amount of harm it can do when it fails by having already prepared some sort of backup system elsewhere.
Another key area will be the software which controls all the different elements of a craft. It will have to be critically examined far more thoroughly than for an unmanned launch, because it not just a dollar value you lose if things go wrong, it becomes a national disaster when crews are lost. Software qualification for manned flight ops tends to be a really long and incredibly expensive process, really only rivalled by the software qualification for controlling nuclear powerstations!
In short, its a process of far more comprehensive checking and mitigating process for problems than is implemented for unmanned boosters. It takes an awful lot longer, and costs an awful lot more.
Ross. -
#213 by Chris Bergin on 03 May, 2006 09:27
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Sergi Manstov - 3/5/2006 9:45 AM
Can users use civil talk when answering people's posts. We will remove those that cannot or lock threads. Zero tolerance.
Ah the wonders of a growing forum.
Everyone will respect, repeat, respect everyone's comments - regardless if they seem like utter bollocks to you or not. If we get any crap from anyone - right out of the door. That's the only way to keep this forum away from the hell holes some of you came from.
I know we've got a lot of high level space industry professionals here - and we've had previous experiences where one lead engineer thought some "jump-start space fan who thinks he's an engineer" was (heaven's forbid) disagreeing with him. Ironically that happened to be "his superior" with a rival launch services company....it just doesn't seem like that when people are using nicknames to post on a forum.
Keep that in mind at all times. Argue, but keep it civil. Any pissing matches and I'll lock threads faster than you can say "but he said my rocket's ISP was shit"
If anyone has a problem, PM or Mail me. -
#214 by rcaron on 03 May, 2006 09:32
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Chris Bergin - 3/5/2006 5:27 AM
Any pissing matches and I'll lock threads faster than you can say "but he said my rocket's ISP was shit"
I literally doubled over laughing when I read that! -
#215 by publiusr on 04 May, 2006 18:24
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Tap-Sa - 2/5/2006 2:05 AM
How come you bash the shuttle, vehicle NASA built, so freely and yet adamantly believe that another vehicle NASA insists on building will be a heaven sent delivering all promises made? Rather ... dualist thinking.
No, it is simple truth. You don't have an orbiter that keeps you in fits all the time. Keeping things civil here--no offence, but I prefer that NASA keep things in house and that we listen to spaceflight veterans there, rather than be subject to Primes who want to build it their way and charge us out the wazoo for multiple EELV assembly costs. That is what we should be suspect of. Griffin keeping things in house is a GOOD thing.
NASA has put more craft in orbit than any one of us has, after all.
With all the flak Griffin has been getting, I'd say he was on target. -
#216 by Jim on 04 May, 2006 22:01
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publiusr - 4/5/2006 2:24 PM
QuoteTap-Sa - 2/5/2006 2:05 AMHow come you bash the shuttle, vehicle NASA built, so freely and yet adamantly believe that another vehicle NASA insists on building will be a heaven sent delivering all promises made? Rather ... dualist thinking.
No, it is simple truth. You don't have an orbiter that keeps you in fits all the time. Keeping things civil here--no offence, but I prefer that NASA keep things in house and that we listen to spaceflight veterans there, rather than be subject to Primes who want to build it their way and charge us out the wazoo for multiple EELV assembly costs. That is what we should be suspect of. Griffin keeping things in house is a GOOD thing. NASA has put more craft in orbit than any one of us has, after all.With all the flak Griffin has been getting, I'd say he was on target.
NASA has no LV design experience. FACT
NASA inhouse costs are higher than the primes
Who are going to build the ESAS LVs? The primes.
Where do you get all this EELV costs and Prime contractors bullying NASA. It is not happening.
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#217 by ericr on 04 May, 2006 22:57
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Chris Bergin - 3/5/2006 4:27 AM
Amen brother!
Everyone will respect, repeat, respect everyone's comments ... That's the only way to keep this forum away from the hell holes some of you came from...
Thank-you Sergi!
Thank-you Chris!
I really enjoy hanging around in your neck of the woods! -
#218 by Kayla on 05 May, 2006 02:43
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kraisee - 3/5/2006 3:56 AM
Quoteyinzer - 3/5/2006 3:20 AM
Look at the table on page 472 of the ESAS full report. An upper stage with 2 RL-10s is predicted to be more reliable than one with one J-2S. An upper stage with four RL-10s is vastly more reliable. "Man rating" is supposed to provide increased reliability; if you already have much higher reliability than engines that are considered acceptable for manned use, what's gained by going through the process?
There are a lot of different factors to consider when man-rating a vehicle. The process involves exhaustive testing, re-testing and analysis over and over again into more things than are checked for unmanned vehicles. Things like determining how an engine might fail is not so important for unmanned payloads because whether it never fires or blows up still normally results in a loss of the payload & the mission. On a manned craft you obviously want to make sure that your engines don't fail at all, but because that's impossible to do realistically, you have to assume failures will happen and make sure they are not going to be life threteneing when they do go wrong. They have to put a lot of work in to make sure that when it ever does fail, it shouldn't fail by blowing up the entire craft as it dies. That may require redesigning some parts to make them stronger, and more cble to survive critical failure modes, or it may just assess that a certain software controlled sequence would be able to shut the engine down safely in case of a detectable problem. Many of these sorts of issues are done on unmanned rockets too, just not as exhaustively and thoroughly as for manned craft.
Also, more generically, there will be an extensive analysis into trying to predict every single type of failure every single element of a vehicle can suffer from and if one failure here will have any effect on another element anywhere else in the vehicle. If you know how a piece can go wrong, you may be able to mitigate the amount of harm it can do when it fails by having already prepared some sort of backup system elsewhere.
Another key area will be the software which controls all the different elements of a craft. It will have to be critically examined far more thoroughly than for an unmanned launch, because it not just a dollar value you lose if things go wrong, it becomes a national disaster when crews are lost. Software qualification for manned flight ops tends to be a really long and incredibly expensive process, really only rivalled by the software qualification for controlling nuclear powerstations!
In short, its a process of far more comprehensive checking and mitigating process for problems than is implemented for unmanned boosters. It takes an awful lot longer, and costs an awful lot more.
Ross.
I'll do my best to be very polite to you Ross...
The question was about the RL10 engine. What specifically with the engine is wrong? The RL10 engine, thanks to its very benign operating conditions, has arguably the lowest cat fraction of any engine in operation. One can abuse it, broken cooling tubes excetra and it still works. I'm only aware of a single failure (ground and flight) that may have caused collateral damage, and this is in thousands of firings.
One can stand behind the term "man rated" all one wants. The key is does a system work in actual practice. The RL10 isn't perfect. I've certainly got improvements that I'd like to make to it, but, wow, it's hard to argue with success
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#219 by Tap-Sa on 05 May, 2006 07:27
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kraisee - 2/5/2006 12:47 PM
The basic elements of the Shuttle, if simply put together in a new way, can be made into vehicles which are far, far safer than Shuttle.
Ross.
I agree completely. What I doubt is NASA being able to build and fly CLV cheaper than what EELV based solution would cost. But IIRC you wrote that you have some new interesting documents with numbers proving otherwise, looking forward to see those.
EELV's were accomplished in a fraction of that time for a fraction of the cost!