2nd CLV giant problem: SINGLE 2nd stage SSME engine

[gaetanomarano]

<br />The total annual budget for space of Europe, Russia and China is less than $3 billion... only NASA has (and will have) a budget for serious space projects... so, NASA projects are the only REAL space projects in the world... and now the "HOT" project is VSE/ESAS<br /><br />I don't know if VSE/ESAS plan is only a "sketch" (that may have many changes in next years) or a TRUE and DEFINITIVE plan (also in its little details!)<br /><br />in both case, any good suggestion may help "the plan" to be better, safer, cheaper, and faster<br /><br />"my" opinion is that the VSE/ESAS plan and its "hardware" (as planned to-day) are FULL of real and potential "mistakes"<br /><br />then, after the thread about 1st stage of CLV, I post a thread about its 2nd stage<br /><br />while the problem with 1st stage is (my opinion, of course) that it can't stop burning at lift-off for a safe launch-abort... the main problem with the 2nd stage is the OPPOSITE<br /><br />the 2nd stage of CLV will use a SINGLE engine, instead of a redundant multi-engines design, so, if it don't works, the CEV/CLV will abort, the crew may have some risks and the ENTIRE moon missions will fails (after a launch-abort, NASA can't try again without MONTHS of investigation to know the real problem of the accident!)<br /><br />in the Apollo13 launch, despite the 2nd stage's central engine fault, the apollo-system reached the orbit with the other four 2nd stage engines<br /><br />the engine will be the same (earth-started) Shuttles' derived SSME, but with some changes for "air-start"<br /><br />the earth-start version was tested 300+ times in TRUE launches, while the new version and its reliability are completely unknown<br /><br />it may work LIKE the past SSME... or BETTER... or WORSE<br /><br />as reported in the posts of two uplink's users, the earth-start SSME have had FIVE faults (with launch abort) that mean a 4.5% of faults compared with all Shuttles' launch<br /><br />that figure may appear "very little"... but, with 25-35 orbit

 

[najab]

Seeing as one engine was good enough for Apollo, and one engine is good enough for Soyuz, one engine is good enough for CLV.

 

[gaetanomarano]

<br />NOT TRUE for both apollo and soyuz rockets

 

[tap_sa]

<font color="yellow">"the question is: "do you think that this SINGLE engine 2nd stage design is good and reliable"</font><br /><br />Yes.

 

[najab]

Yes true. Do some reading.<br /><br />Apollo's third stage and Soyuz's second stage are both single engined.<br /><br />Please, really - do some reading, you might actually learn something.

 

[gaetanomarano]

<br />1. the saturnV 3rd stage was used for trans lunar injection<br /><br />2. the 2nd stage of apollo13 saturnV sent the apollo in orbit thanks to its 5-engines design (with one engines aborted)<br /><br />3. true for the 2nd stage soyuz rocket, but it was tested in 100+ TRUE flights<br /><br />4. the 2nd stage SSME was designed for earth-start (and failed in 4.5% of flights), then may fails with air-start<br /><br />5. an aborted soyuz launch (with crew alive) mean $60 million lost, an aborted CEV/CLV launch mean up to $8 billion lost (with moon missions)<br /><br />6. the question is if one SSME is good and reliable for CLV (not if "another" engine is good for "another" rocket)<br /><br />7. a 20% (only) fails of the SINGLE (1st stage and/or 2nd stage) engines mean up to four moon missions failed<br /><br />another (possible) "alternative" question may be: "do you think that use a non-redundant design worth the risk to lose so much money and missions?"<br /><br /><br />the sum of CEV/CLV possible fail + SDHLV possible fail + LSAM possible fail + SM possible fail... may reach a global 50-70% of moon missions failed (like explained in my "locked" thread...)<br />

 

[carp]

GAETANOOOO!!!! http://img446.imageshack.us/img446/4788/malocchio2hd.jpg

 

[dobbins]

"another (possible) "alternative" question may be..."<br /><br />The best question would be "is my dog a better source for space information than Gaetano?"<br /><br />The answer is Yes, because he will give no information at all instead of distortions, wild numbers, misinformation, invalid assumptions, and baseless opinions.<br /><br />

 

[najab]

><i>...the saturnV 3rd stage was used for trans lunar injection...</i><p>The S-IVB was used to put the CSM/LM combination into orbit as they were too heavy for the second stage to manage. Remember, however, that the Saturn V wasn't the only Apollo rocket...<p>><i> true for the 2nd stage soyuz rocket, but it was tested in 100+ TRUE flights</i><p>But it wasn't tested 100 times when Yuri got on board, in fact it wasn't tested 100 times until the 101st flight.</p></p></p>

 

[gaetanomarano]

<br />CARP!!!!!!!!! (I don't know your real name) http://www.ourtimelines.com/hist/challexp.jpg

 

[propforce]

<font color="yellow">"... the earth-start version was tested 300+ times in TRUE launches, while the new version and its reliability are completely unknown .......... consider that, the "never long-tested" (not 300+ times like the earth-start version) "air-start" SSME, may fails in 8%, 12%, 20% or more CEV/CLV flights... "</font><br /><br /><br />Do you know the differences in engine operating characteristics between "earth start" and "air start" ??? <div class="Discussion_UserSignature"> </div>

 

[strandedonearth]

But wait! There's more! (faulty assumptions, that is)<br /><br />Let's see, 5 on-pad aborts = 4.5% SSME failure rate? But wait! There's 3 engines per flight! Assuming the faults were confined to one engine that really means that only 1.5% of the engines had a fault requiring a shutdown.<br /><br />As najab pointed out, you, gaetanoooooooo, have just proven once again that you don't have a clue what you're talking about. All I get out of your posts is "the sky is falling! the sky is falling!"

 

[gaetanomarano]

<br />old car was very risky... new car (with best structures, ABS, airbags, etc.) are safer... I suggest to build all ESAS' modules like NEW cars... NOT like an OLD cars

 

[gaetanomarano]

<br />not exactly... it may need an ignition-system (now on earth) that fly with the engines... but what impressed me is the fact that SSME's manufacturer will need three years to modify the engine... then, it is not a "minor change"

 

[carp]

After Gaetano's criticisms....CEV new configuration. http://img334.imageshack.us/img334/5645/cevmalocchio4fl.jpg

 

[gaetanomarano]

<br />this is a good pro-CLV argument (the FIRST I've read so far in over 2000 posts... to be honest...) ...but the money and human lifes are too much to use a low-redundancy system<br /><br />when I remember the apollo missions, I think (FIRST) that all the astronauts was VERY LUCKY... one engine to enter lunar orbit, one engine to land on the moon, one engine for moon departure, one engine for lunar orbit departure... a very poor-redundacy... a very high risk = very lucky astronauts<br /><br />I suggest that ALL future vehicles (CLV, LSAM, etc.) and missions (orbital, moon, mars and beyond) will have a VERY HIGH redundancy (if you have patience read some of my posts about this argument)

 

[gaetanomarano]

<br />some psychologists thinks that the REAL (unconfessed and unconfessable) reason of the people's high interst (and high audience) of risky sports (like car races) and extreme shows (like walk throught two high buildings on a little wire) is NOT the "race" or the "show" but the (secret) "hope" of a spectacular accident! (or, BEST, a mortal accident!)<br /><br />if they are right... probably... the most "exciting" part of space and moon missions are NOT the mission by itself (or the "science") but its HIGH RISK<br /><br />probably... many "hope" (in their subcoscience) that high risk missions will give them another "exciting" Apollo13 (but with 3D real-time images and Dolby Surround...) while too much redundant, safe and perfect missions (with the minimum possible risk) may be very boring!<br /><br />of course, this is for "non-contractors peoples"... other peoples may want the ESAS plan "as is" for "different" (and always "unconfessable") reasons...

 

[gaetanomarano]

<br />you're right... the engines failed while it works in earth departure... but without the other four engines the missions aborted before reach the orbit... this is the problem...

 

[SpaceKiwi]

<blockquote><font class="small">In reply to:</font><hr /><p>also, consider that, the "never long-tested" (not 300+ times like the earth-start version) "air-start" SSME, may fails in 8%, 12%, 20% or more CEV/CLV flights... so, the number of orbital/lunar missions failed may be FIVE or more... with up to $40 billion lost and 30% of moon missions failed before they really start!!!<p><hr /></p></p></blockquote><br />I'm frankly surprised, given your 'concern' that the single 2nd stage engine might not start 1st time every time, that you're not advocating a solid motor for this purpose.<br /><br /><img src="/images/icons/rolleyes.gif" /> <div class="Discussion_UserSignature"> <p><em><font size="2" color="#ff0000">Who is this superhero?  Henry, the mild-mannered janitor ... could be!</font></em></p><p><em><font size="2">-------------------------------------------------------------------------------------------</font></em></p><p><font size="5">Bring Back The Black!</font></p> </div>

 

[josh_simonson]

I'd expect the one shot engines to go through more testing and qualification than the STS engines where they can start them up and see what happens.<br /><br />Still, this is a good point. Engine out capability would certainly be nice, but the SSME is the only US, man-rated engine they've got at the moment. Some thought was given to reviving the J-2S though.

 

[frodo1008]

HOORAY!! Someone besides myself that actually understands what has to happen here!! Although I should know that at least the most knowlegable person on these boards would know this!!<br /><br />I know this as I actually was an inspector at Rocketdyne that helfped check many of the individual parts for these engines!! Many times minor improvements could have been made to these engines, but they weren't made right away as the testing needed to recertify such engines was far too expensive for any smaller changes!! What many don't seem to realize is that these engines are man-rated hardware, that are also in the critical path for the safety of the entire shuttle system. So ANY changes made, small or large are going to have to require very extensive quality testing to recertify the engine design changes! When a much larger change is needed and justifyable, then the smaller changes themselves can also become incorporated (Microsoft also does this kind of thing with major changes to its software). <br /><br />I really don't know how large a change it is going to be to go to this air start configuration, but I DO know that when this change is done the actual engines (as I have already pointed out in one of my former posts) is going to have literally thousands of seconds of testing! <br /><br />The management of Rocketdyne, and its engineering department is very well enough versed (and also they are now a part of the very same company [Pratt & Whitney] that was responsible for the last major changes) in this engine that if such a change was going to be too great a problem they would say so!! <br /><br />Three years IS NOT an excessive amount of time to make any changes to these very important man-rated and NASA certified engines!! <br /><br />Is this not enough information to have you stop on this subject now gaet, or do you just wish to continue to run off at the keyboard!!!!!!!

 

[propforce]

<font color="yellow"> "...I really don't know how large a change it is going to be to go to this air start configuration, but I DO know that when this change is done the actual engines (as I have already pointed out in one of my former posts) is going to have literally thousands of seconds of testing! <br />.."</font><br /><br />The changes have been studied extensively and (most likely) within Rocketdyne's experience. You're rightt, however; any configuration changes will need extensive qual/ re-cert testing to <i>demonstrate</i> it meets the man-rated requirements. <div class="Discussion_UserSignature"> </div>

 

[gaetanomarano]

<br />no, because the 2nd stage engine/s must burn for the exact time and with the exact thrust to reach the exact orbit... a solid rocket can do it... it burns until fuel ends

 

[propforce]

<font color="yellow">"... the 2nd stage engine/s must burn for the exact time and with the exact thrust to reach the exact orbit... a solid rocket can do it... it burns until fuel ends ..."</font><br /><br />A 2nd stage engine will burn until you run out of propellant or when you get to orbit, whichever comes first <img src="/images/icons/smile.gif" />. Although I think what you were trying to say is that a <i>liquid engine</i> can shut down whereas a solid rocket can not. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> </div>

 

[gaetanomarano]

<br />why lose time and money if you can do it with many engines