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

[gaetanomarano]

<br />of course... but I hope they put sufficient gasoline in its tank...

 

[haywood]

I can't believe this guy!<br /><br />He's quoting his own old warped postings to bolster his current (and equally flawed) postings.<br /><br />Sounds to me like he's talking to himself.<br /><br />And another thing...<br /><br />I've never heard him apologize for spewing bad information or assumptions or thank anyone with greater knowledge than himself for correcting him on a mistake.<br /><br />We have a word for that in English...<br /><br />Arrogance.

 

[gaetanomarano]

if you want to insult me... ok (you're not the first an will be not the last)... but what you say is false<br /><br />if an users that know better than me a specific problem post a correction, that post is good "as is"... I can't post a reply to confirm that his info is real... I post an info only if I've a different opinion or a different info or a different source<br /><br />about... "He's quoting his own old warped postings to bolster his current (and equally flawed) postings"<br /><br />can you better explain me what you say (it's a problem due to "my" english) thank you<br /><br />about my posts... read them! ...you will find MANY "agree", "true", "right" and (also) some "thank you"...

 

[kdavis007]

Why are you posting crap? Why do you want to keep the shuttle?

 

[gaetanomarano]

<br />do you REALLY want to know my opinion... or it is another opportunity for you to post insults?<br />

 

[dobbins]

Maybe you ought to stop and think "why are so many people hostile to me?"<br /><br />You might discover there is a reason for what you are dismissing as insults.<br /><br />

 

[josh_simonson]

It admits in the ESAS document (around section 6) that the failure of the SSME will cause a loss of mission - but the SSME was more reliable and had better performance than the alternatives.

 

[najab]

Most (all?) upper-stages use a single engine - even if they had used an engine other than an SSME, engine failure would lose the mission.<br /><br />This is something our Italian friend seems not to grasp.

 

[SpaceKiwi]

Our Irish-Italian friend is an armchair rocket-designer, trapped in the body of an Uplink contributor.<br /><br />Fortunately (for all of us, not least, him) his 'designs' will never see the light of day or black of space. <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]

Centaur uses 2 RL-10s - but may not have engine out capability. It'd take at least 14 of the buggers to loft the CEV tho.

 

[gaetanomarano]

<br />a military (solid/liquid/single/multiengines) rocket launch only an unmanned weapon<br /><br />a commercial (solid/liquid/single/multiengines) rocket launch only an unmanned satellite<br /><br />a russian (solid/liquid/single/multiengines) rocket launch a manned (but very low cost) caspule (or a cargo)<br /><br />CLV will launch the biggest (and, I think, the MOST expensive!) manned capsule of the space-story with four astronauts on the top... while a ($5 billion per launch) LSAM+booster wait in orbit for it...<br /><br />the "Irish-Italian friend, armchair rocket-designer, trapped in the body of an Uplink contributor" thinks that it is a crazy idea and suggest to use a multi-engines design with extra-thrust (to work also if one engine will fails)<br /><br />but probably you (and CLV designers) are confident that one engine is sufficient... ok<br /><br />we (me and you) don't have a good (your) and a bad (mine) opinion... we have (both) "an opinion"... only real CLV flights may give us the real figure of CLV launch failures due to its single engine design... that figure may be zero or may be high... we can't know it now<br /><br /><br />but (sorry) it's incredible for me to read here that you (absolutely!) want this "loved single engine" insted of the better, safer and most reliable design for your astronauts (and your money...)<br />

 

[nacnud]

So you want NASA to:<br /><li>Design two new liquid engine designs, one for t five engine first stage and one for a five engine second stage.<br /><li>Design two new stages, I expect you would want them recoverable as well so that they can be examined of faults after use.<br /><li>Design a new smaller 4 man CEV, probably with wings because you think that is safer, oh and give it the ablity to abort to a ocean landing just in case<br /><li>Design and build the launch infrastructure needed for such a craft<br /><br />And do all this cheaper than the current plan.</li></li></li></li>

 

[gaetanomarano]

<br />I dont "want" nothing... I only give my opinions<br /><br />my first suggestion is to build a 10-12 ton CEV and launch it with the best (under NASA evaluation, of course) ready available mid-rocket with all the safety changes it need for manned flights (despite, a good LAS, already IS a complete crews' safety device)<br /><br />this solution is FAST, CHEAP and RELIABLE (also, with a low cost per launch, much more launches will be possible with the same money... and... more launches... mean more experience!)<br /><br />if NASA (absolutely) want to build a big CEV and a new rocket... I suggest to use two SSME (already tested and used for earth-start without any extra-research) for the 1st stage and four/five little liquid-engines (already used in other rockets... NASA may knows the better engine to use), with extra-thrust design, for its 2nd stage<br /><br />the two SSME will cost three times one SRB but the CLV 1st stage will be REUSABLE while, the single (and very expensive... due to extra-research) 2nd stage SSME will be EXPENDABLE

 

[gaetanomarano]

<font color="yellow">"...his 'designs' will never see the light of day or black of space..."</font><br /><br /><br />why not?<br /><br />if I (or you) will have the opportunity to design REAL rockets, I (or you) will ACTUALLY design and launch them!<br /><br />why not?

 

[strandedonearth]

Keep on contradicting yourself. Any currently available booster only has 1 or 2 engines per stage. There goes your engine out capability. As for using 2 SSME's in a reusable first stage, SSME's don't like salt water landings and would probably cost more to refurbish after such a dunking than a new one. SRB's, on the other hand, are reusable after an ocean recovery, and the CLV version will probably be re-used if the nitty-gritty details can be ironed out.

 

[gaetanomarano]

<br />true... but ready available rocktes' reliability is already known while the knowlendge of CLV reliability is ZERO... CLV will be a 15/25-launches "experiment" made with REAL astronauts and REAL money!<br /><br />also... with a 12 tons CEV and a low cost mid-rocket, each launch may cost 1/3 of one CEV/CLV launch... then a "redundant-mode" two-CEV-ready-one-fly will be possible REDUCING VERY MUCH the risk of a (very expensive) moon mission's FULL ABORT<br /><br />the CEV and the rocket that don't fly will be not "money lost"... they can be used next time<br /><br />thanks to its low cost, the mid-rocket may be fully expendable<br /><br />don't forget that SRB is the ONLY reusable part of a CLV... its new version may cost $50 million... but these are NOT "$50 million saved"!<br /><br />after a launch you may recover only the rings and the nozzle of an SRB... the REAL saving may be around $10 million per launch!<br /><br />the choice is:<br /><br />a) use a 12 ton CEV with a mid-rocket and save $600+ million per launch... or...<br /><br />b) use a CLV and save only $10 million per launch (the SRB's scrap!)

 

[propforce]

<font color="yellow">....the "Irish-Italian friend, armchair rocket-designer, trapped in the body of an Uplink contributor" thinks that it is a crazy idea and suggest to use a multi-engines design with extra-thrust (to work also if one engine will fails) <br /><br />but probably you (and CLV designers) are confident that one engine is sufficient... ok <br /><br />we (me and you) don't have a good (your) and a bad (mine) opinion... we have (both) "an opinion"... </font><br /><br />Suppose we design the CLV 2nd stage with 2 engines, let's visit the scenario of what happen when one of the 2 engine failed during boost?<br /><br />If you 'design' the thrust of each engine such that you need <i>both</i> engine thrust to give the stage a positive acceleration then, with one engine out, you're out of luck. The only option is to abort, which means the CEV plunges back from ~ 300K feet back. No different as if the CEV reentry from orbit. The crew's life is not endangered.<br /><br />Suppose you 'design' so that the thrust of each engine alone will get the CEV to orbit the, if both engine work as expected, you'll have to require engine can throttle to 50% of its power at the beginning of the burn, and down as much as to 20% near at end of burn. This is beyond the technology level of today's liquid rocket engines. So you'd spend another billions of $$$ with another 10+ years of delay before launching CLV?<br /><br />Another consideration, if you 'insist' on putting 2 SSMEs on CLV, with each engine weigh at 7,500 lbm, that's the weight you'll take away from the CEV as payload (more if you add other support equipment). That extra half-ton weight could mean additional safety/life support equipment on the CEV instead. For every pound of "extra' weight you put on the stage in the name of "safety", you'd take the same weight away from the payload. Eventually you'll reduce the CEV capability such that you'll need MORE launches just to make a Moon mission.<br /><br />So Mr. irish <div class="Discussion_UserSignature"> </div>

 

[dobbins]

"why not?<br /><br />if I (or you) will have the opportunity to design REAL rockets, I (or you) will ACTUALLY design and launch them!<br /><br />why not?"<br /><br />Because only a total fool would let somene with as little knowlege of rockets as you have shown design one.<br /><br />

 

[gaetanomarano]

<font color="yellow">need both engine thrust to give the stage a positive acceleration then</font><br /><br />if you read my previous posts you may discover that I've already made the same consideration you post here... if the multi-engines' stage don't have a 20-30% extra thrust, on engine fails is like a single engine design fails... the launch aborted<br /><br />in brief... no one design can give 100% safety and success... not even a 20-engines' design... I suggest a four/five little engines' design for 2nd stage with 120-130% thrust, so, they will work around 80% of its max thrust in normal flights... not 50%<br /><br />about SSME weight... you must compare the weight of the entire 1st stage not only of engines

 

[propforce]

<font color="yellow"> I suggest a four/five little engines' design for 2nd stage with 120-130% thrust, so, they will work around 80% of its max thrust in normal flights... not 50% </font><br /><br />That means another engine development program with another 4~5 years of delay. <br /><br /><font color="yellow">about SSME weight... you must compare the weight of the entire 1st stage not only of engines </font><br /><br />Huh, thought we were talking about the 2nd stage? <div class="Discussion_UserSignature"> </div>

 

[gaetanomarano]

<br />I suggest to use four/five ALREADY available engines for 2nd stage (NASA may choice the better engine for that purpose)<br /><br />that mean 3+ years SAVED since, ONLY to modify the SSME, its manufacturer need 3 years of research and tests!<br /><br />I suggest to use two (already available) earth-start SSME for the 1st stage

 

[najab]

><i>I suggest to use two (already available) earth-start SSME for the 1st stage</i><p>That gives you a liftoff thrust of ~840,000lbs - less than 1/3 of the thrust of a single SRB - and barely enough to lift your rocket off the pad. Once we fire the hold-down bolts it'll rise a couple inches off the pad and fall back down in a fireball.<p>What an improvement. <img src="/images/icons/rolleyes.gif" /></p></p>

 

[gaetanomarano]

<br />the better way is to use the new (liquid-engines' 1st stage) with a 12 ton CEV (much better... use an already available rocket instead of a CLV)<br /><br />I will search more data about rockets for comparison... but other existing rockets don't appear to have much more thrust to reach the orbit with an heavy payload<br /><br />remember that, after SRB separation at 150,000 feet, three SSME are able to accelerate to orbital speed over 200 tons (Shuttle+payload+tank+propellant)<br /><br />a liquid engine may give the same acceleration to reach orbital speed with less thrust and more time<br /><br />the giant acceleration and high speed of an SRB is another problem (not an advantage) of CLV 1st stage

 

[frodo1008]

Rocket engine developement, building and testing is indeed a time consuming activity. Rocketdyne, with far more expertise in these matters than you has stated that from contract go ahead till competed testing, designing and building an air start SSME will take some 3+ years. Certainly less than 4 years. So if such a go ahead is given by the end of 2006 (and I would imagine it would be) then such an engine would be ready to install by 2010. As the shuttle itself is just going to be fully retired by then, and full testing of the complete single stick SRB CEV will not start at least until 2011, your worries over the time to develope such an engine are apparently fully addressed!!

 

[najab]

><i>the better way is to use the new (liquid-engines' 1st stage) with a 12 ton CEV</i><p>gaetanomarano, you can't get 12 tons into orbit using a first stage that has 2 SSME's - the maths just doesn't work.</p>