NO safe liftoff-abort-mode for 1st stage CLV solid fuel SRB

[gaetanomarano]

<br />to moderators<br /><br />this post http://uplink.space.com/showthreaded.php?Cat=&Board=missions&Number=414330&page=0&view=collapsed&sb=5&o=1&vc=1 disappeared without any editing, how can I recover the full text?<br /><br /><br />

 

[strandedonearth]

It seems the issue here is if the first stage ignition shakes the stack up enough to cause something higher than the first stage to fail, then the SRB cannot be shutdown. But can you name any mission, manned or otherwise, where something higher in the stack got shook up enough during the first stage ignition sequence to cause an abort, shutdown or catastrophic mission failure? <br /><br />I feel safe in assuming that the upper components of the stack will get shaken up far more in the testing chambers than they ever will on the launch pad.

 

[strandedonearth]

"must have many "red lights"" <br /><br />Of course there will be plenty of red light bulbs, but I doubt many of them will actually light up during the first or subsequent launches. Come to think of it, there'll probably be less red light bulbs on the CEV than on any previous vehicles, as most warnings will probably come through computer screens.

 

[gaetanomarano]

<br />after 50 years of safe liquid (and multi) engines manned flights that can stop at lift-off (see some posts here about SaturnV) the use of a SINGLE solid-fuel for the 1st stage appear a risk to me<br /><br />I've already explained many times my opinion, but I can't insist for weeks on this point... I prefer to discuss about other CLV (possible) problems<br /><br />about "catastrophic failure"... a "system" that must work for up to six weeks in stand-by (as planned with CEV/SM) need to be perfect, also in its little (non catastrophic) functions... like... the astronauts' toilet...

 

[gaetanomarano]

<br />"red light" mean "alarms" not "light bulbs"

 

[SpaceKiwi]

<blockquote><font class="small">In reply to:</font><hr /><p>all complex systems have some "red lights"... and spaceflights are VERY complex system<p><hr /></p></p></blockquote><br />And, as the A-380 has demonstrated, modern design techniques mean that vehicles can be built to a much higher level of 'performance-certainty' than ever before.<br /><br />As SoE has already noted, the majority of potential problem areas can be simulated and have the begeezus tested out of them during the design process. You are right when you say no system will ever be perfect right off the bat, but it is equally true to say that you will never reach that unattainable goal.<br /><br />All you can hope for is to refine your methods of design and construction as you accumulate knowledge along the journey. Which is precisely what NASA and its contractors have done regards the SRB 1st stage. They have weighed up the theory versus the reality versus the workarounds versus the operational history versus the technical improvements versus the safety improvements .... and, they have come to the conclusion that a SRB 1st stage (<b>no shut-down warts and all</b>) provides the <b>best</b> possible solution to the design problem in front of them. <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>

 

[strandedonearth]

Well I apologize, I realize english as a second language isn't easy, but your context implied that the red lights were merely present, not actually lit. But I have no reason to believe that a first stage ignition of a liquid or solid booster will set off red lights elsewhere in the stack. And you still haven't cited any examples of when ignition shook up the stack enough to trigger alarms somewhere besides in the first stage, which is the point you were expounding on.

 

[strandedonearth]

Ack! Thanks, SpaceKiwi, that's the first time someone has abbreviated my handle that way, and made me realize it has the same initials as Sony Online Entertainment. Given how SOE has recently ruined their game Star Wars Galaxies (or at least my enjoyment of it), I don't care much for that acronym <img src="/images/icons/frown.gif" /> Ah well <img src="/images/icons/smile.gif" /><br /><br />I now return you to your regularly scheduled, uh, thread.

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>after 50 years of safe liquid (and multi) engines manned flights that can stop at lift-off (see some posts here about SaturnV) the use of a SINGLE solid-fuel for the 1st stage appear a risk to me<p><hr /></p></p></blockquote><br /><br />FYI, in the event of a pad abort on Apollo, they were not going to simply shut down the Saturn. The escape system had the capability of pulling the capsule free even on the pad and bringing it to a safe splashdown downrange in the Atlantic. A Saturn V could make a very big boom in the event of a truly catastrophic failure -- such as, perhaps, debris in a propellant line being ingested by a turbopump, which then throws one or more blades, quite possibly taking out a neighbor or two and probably sparking a chain reaction destroying all five engines rather violently. A sort-of-similar scenario killed at least one of the Soviet N-1 rockets; I used to remember the history of those four flights better, but I don't recall the details off the top of my head at the moment. Anyway, suffice it to say that liquids can be ugly too. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[SpaceKiwi]

Actually, SoE, SOE has a unique but widely understood meaning here in New Zealand. It is an abbreviation for the term 'State Owned Enterprise', which was coined to label those few businesses the NZ Government decided to hold onto after they turned the economy 'free-market' and sold off things like the national railway and the national grid and the national telecommunications network.<br /><br />When I saw your handle abbreviated as such, I couldn't resist using it. <img src="/images/icons/wink.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>

 

[drwayne]

There were also some two engine out scenarios as I recall that took the Sat 5 really close to the VAB.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[drwayne]

Found a reference:<br /><br />http://yarchive.net/space/launchers/saturn_v_failure.html<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[strandedonearth]

Hmm, not sure if I care to be a State Owned Enterprise either. But that must be better than being associated with Sony Online Entertainment. Hmm, actually, maybe I could move to NZ and get a subsidy <img src="/images/icons/wink.gif" />

 

[gaetanomarano]

<br />as you agree, only "perfect" vehicles don't need any abort/emergency procedures... but "perfect" vehicles don't exists<br /><br />the A-380 may be the best and safest airplane of the world but (you can be sure!) its pilots must learn on its flight-simulator a very high number of "emergency procedures" before fly with it<br /><br />the problem is simple<br /><br />a very complex and expensive system like CEV/SM/CLV must have lots of launch-abort procedures, from the first day it will arrive on the launch pad while its countdown to the last second of its flight in space<br /><br />for great part of this procedure an "abort-mode" is possible... in the last (and very critic!) seconds after engine-ignition it will be NOT possible due to solid-fuel SRB (or it WILL BE possible with a liquid engines)<br /><br /><br /><br /><font color="yellow">"...you can hope for is to refine your methods of design and construction as you accumulate knowledge along the journey..."</font><br /><br />unfortunately, spaceflights' experience is of only a few hundreds manned flights (and only two dozens with CEV) while commercial airplane experience is of MILLIONS real flights (and accidents... that kill many people, but add knowlendge to build better airplanes)

 

[mlorrey]

gaetano,<br />I myself dislike the use of the SRB in the stack. IMHO it is just makework jobs welfare for the SRB refurbers and to keep the ICBM industry happy. It has terrible Isp and is expensive. It puts no reusable tankage in orbit to be turned into spacehabs. <br /><br />But safety is not one of my concerns with it. It will be many times safer than the STS system was.

 

[gaetanomarano]

<font color="yellow">you still haven't cited any examples of when ignition shook up the stack enough to trigger alarms somewhere besides in the first stage, which is the point you were expounding on</font><br /><br />to give you an exact answer I must be a control-centers' engineer<br /><br />an experienced control-centers' engineer or employee may have probably seen in his life more flashing "red-light" alarms than a Christmas' tree...

 

[gaetanomarano]

<br />I don't know the SaturnV launch-abort at lift-off procedures (and I don't want another "wrong" from shuttle_guy...) but I suppose that it was...<br /><br />1. hold-down the rocket<br /><br />2. launch as fast as possible the capsule in a safe place with LES<br /><br />3. close the engines' valves<br /><br />4. "hope" that engines stop burning in time to save the rocket and the launch pad<br /><br />5. reuse the rocket if it remain in good conditions

 

[gaetanomarano]

<br />but STS is so complex and made with so much parts that its realiability can't be compared 1:1 with a simple booster<br /><br />in other posts I've said that SRB may be the BETTER rocket of the world, but it can't stop after igition... NOT because it is an SRB... but because it is a solid-fuel rocket... this is its problem, not its reliability as rocket alone

 

[strandedonearth]

But you still haven't demonstrated why not being able to stop an SRB is a problem. Put up or shut up. In any event requiring an abort, the crew will be saved by the LAS.

 

[gaetanomarano]

<br />I remember a Shuttle flight (delayed?) due to a woodpecker try thirling the Shuttle's external tank foam<br /><br />I can't know how many and which problems may need a CLV launch-abort since not even NASA knows them (since the CLV don't exist and it need to fly to know its problems!)<br /><br />a liquid-engine may give a 100% timeline launch-abort option while an SRB may give only a 99% (and the remain 1% is the very critic lift-off segment)<br /><br />I've already said that LAS "may" save the crew... but, why risk a "real test" with human lifes aboard?<br /><br />also, if LAS saves the crew... which "LAS" may save... rocket/SM/launch-pad/LSAM+booster/moon-missions/$6+billion???

 

[Swampcat]

<font color="yellow">"...NOT because it is an SRB... but because it is a solid-fuel rocket..."</font><br /><br />Gaetano, SRB is short for <b>S</b>olid <b>R</b>ocket <b>B</b>ooster. <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>

 

[Swampcat]

<font color="yellow">"...a liquid-engine may give a 100% timeline launch-abort option while an SRB may give only a 99% (and the remain 1% is the very critic lift-off segment)..."</font><br /><br />You are making mountains out of mole hills. You've admitted that you have no idea what the safety record of the CLV will be. You're "opinion" has been noted and found lacking.<br /><br />Perhaps you should give this up and start another thread about something else. <img src="/images/icons/rolleyes.gif" /> <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>

 

[gaetanomarano]

<br />"solid-fuel rocket" was NOT the result of the acronym "SRB" but only "a rocket with solid fuel inside"

 

[gaetanomarano]

<font color="yellow"> You're "opinion" has been noted and found lacking.</font><br /><br /><br />no... my opinion is true... but I hope to have better critics...<br /><br />e.g.<br /><br /><font color="yellow">you have no idea what the safety record of the CLV will be</font><br /><br /><br />I, you, NASA and anyone will design a rocket NEVER can have any "safety records" BEFORE a rocket will REALLY exist and fly MANY TIMES to have precise figures!<br /><br />ask me (NOW) for CLV "safety records" is like want to know from me the score of a next month's basket play

 

[strandedonearth]

Gee, what a surprise, you STILL haven't answered the question: Why is not being able to shut down an SRB, or any other SRM, such a problem, given the presence of a LAS? Given that an SRB requires no moving parts to produce thrust, it does not require the post-ignition time for checkout and building thrust before liftoff. Therefore there is no cause to shut it down on the pad. It lights or it doesn't.