New Mars

I know everything I need

probably you've found that info following the NASA link published in my Aug 12, 2006 SRB-article's update here: www.gaetanomarano.it/articles/011srb5.html

...and its REAL performances are unknown now (since, to-day, it doesn't exist)

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He is probably right based on his assumptions.

Criticize his assumptions, not his intelligence.

I'm probably in the same boat, btw.

"he" GCNR or "he" me?

Was directed to GCNR about you.

He (gaetanomarano) is...

You have actually looked at his website and such, right Michael?

Okay then say for a moment that he's not crazy etc etc:

Why did he say the five-segment booster isn't powerful enough and admits that we don't know the actual performance of said booster?

Back to reality where gaetano is nuts, he has made the same argument about other things over and and over and over again: that he is right about his statements (most often about NASA being wrong and he being right), but when challenged - this has happened again and again - "oh but we don't know I'm not right(!!!)" And then demands we assume he be right until we know with total certainty that he isn't as well as demanding we prove a negative.

He's not here to debate and discuss

also a 10-years old student is able to say that, if a car has +22% of weight and (only) +9% of power vs. another car, the first car has LESS performances than the latter... only IF the 5-seg.SRB can add a +25% of extra-thrust may give the power to lift the (planned) Ares-I payload (but we don't know, now, if it can do that, or not) while (if it CAN'T) the newSRB will have (only) too much "extra dry mass" to lift ...don't forget that latest weeks' rumors about an "underpowered Ares-I", don't come from my (five months ago) article...

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No I haven't really looked at gaetanomarano's website (frankly it is a little hard to read). However, I think you both make the mistake of being overly-fanatic, albeit in opposite extemes.

You should know well what you don't know. And show clearly where you make assumptions.

Apparently gaetano doesn't understand the concept of irony: "its obvious that NASA is full of lies" with "oh but we don't know" in the very same breath. Its self-contradictory. Claiming that he's just parroting the Ares-I rumor mongers but "oh THEY said it" is just weaseling. Either the booster is not powerful enough (assertion) or else it is too dissimilar from any previous version such that comparisons are irrelevant ("we don't know"). One or the other.

Thrust thrust thrust all thrust... gaetano doesn't seem to understand much about rocketry either, that thrust influences but does not determine payload. A slower burning rocket conserves its fuel and can burn longer, especially nice for Ares-I since it probably has too much thrust actually (5G acceleration estimated vs 3G for Shuttle). And if the new fuel is more efficient, then less thrust can still provide the same payload or better. Furthermore, the five-segment booster adds more fuel but doesn't add much to the heavy metal end-caps or nozzle necks, making it more efficient pound-per-pound.

since the new SRB doesn't exit now, the "underpowered" rumors may come from recent ATK tests and/or Ares-I design calculations and/or computer simulations

that is true for a liquid stage or for a longer-burn SRB, but, all NASA and ATK claim, specs and tests talk of ONLY five second more burning time on the new SRB (vs. the old) then, NO "burn longer" and the new SRB absolutely NEEDS the expected extra-thrust (to avoid penalization from the extra dry mass)
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Oh yes! ATK would go out of its way to spread rumors questioning the viability of their product! Makes perfect sense!

But you also ignore the change in propellant, which affects the characteristics. Also since a significant portion of the boosters' dry mass is the end cap and nozzle throat, which won't be much heavier, then it doesn't need as much thrust.

no, of course... but these are "secrets" hundreds peoples (at NASA, etc.) knows, then...

infact I evaluate/indicate the dry mass increase around 22% of a standard SRB
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But ultimately you don't know

You don't even know how much the performance of the booster, with any version of the booster, affects the payload of the rocket.

And please, "the rumors might be from real ATK/NASA/etc engineers!" ...and they might not. How do you know? At least as much weight should be given to the chance they are not, and thats assuming the rumors aren't lies.

22% huh? Where do you get that from? Adding an additional segment to the existing four-segment design but not making the end-cap or nozzle throat much bigger increases mass by a quarter? Thats fishy math.

I don't know where "rumors" come from, but (you know) they are MANY and (sometimes) TRUE

this is my evaluation of the extra-weight for the 5th segment without the SRB cap... however, I'm not sure of that since the 1st/2nd interstage module may weigh MORE than an SRB's cap
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Could the Ares VII perform Dr. Robert Zubrins four man, Mars Direct Mission with only two launches per landing?

I had to ask.

It would if it could be built. But frankly Ares VII is too heavy to be transported on the crawler, and would require significant pad modifications over Ares V.

I think Mars Direct originally called for a 130 tonnes to LEO booster, the same as the Saturn V, and the same as Ares V. With a higher-thrust upper stage, Ares V looks just like the original Ares.

However, the question is then whether Zubrins mass estimates will work, and many think they won't.

Personally, I would prefer something in the 160 tonne range. But it looks as though Ares V might be the biggest you could get away with at KSC.

Oh but you don't know

And the interstage doesn't have to resist the leading edge compression of hgih supersonic flight.

Please show your mass assumptions for the various components then we will be able to assess your calculation. Thank you in advance.

AND if you are going to try and calculate payload, show your reasoning and calculations. Not just "oh but the rumors might actually be from anonymous NASA engineers who might not be lying(!!!)"

Plus, the end cap is not the nose cone: the end cap is a thick steel disk on the top end of the booster that prevents the hot high pressure gasses from escaping. The nose cone sits on top of this.

when a news goes to the press EVERYONE can know it
[quote]...the interstage doesn't have to resist...[.../quote]
we are not talking of its resistence to compression, but of its MASS (that does the FULL flight of the SRB) ...the interstange mass is unknown now, but I feel it will be much more than the top of the SRB weight
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back to elementary school, teachers!

ok...

according to Astronautix [ www.astronautix.com/engines/srb.htm ] the SRB data are:

standard SRB gross mass: 589,670 kg.

standard SRB empty mass: 86,183 kg.

then, the total SRB solid propellent mass is: 503,487 kg.

and the SRB segment propellent mass is: 125, 871 kg.

if we add (only) the 5th segment propellent mass, we have: 715, 541 kg.

we must add the dry mass weight of one SRB segment ...unfortunately, I've not found a source for the exact weight ...then, I've assumed a weight around 9 mT: SRB dry mass, less 12 mT for the (scrapped) recovery system, less 2-4 mT for the top parts of the standard SRB (not used with the Ares-I) less 2/7th of weight for the down parts/nozzle/TVC/etc. of the SRB

so, the 5-seg.SRB GLOW will be in the 724.5 mT range ...that is (around) +22.8% of the standard SRB mass... a little MORE than my previous evaluation, NOT less... and it is a further mass the new SRB must lift! ...also, we must ADD (when we will know it) the interstage mass!

think that, if the newSRB's (5th seg. + interstage) extra-mass wil be too much, the REAL increase of payload (vs. the standard SRB) may result RIDICULOUS ...especially if compared with the (3+ years) R&D time and ($3 billion) R&D costs the newSRB will need.......

then, if the 5th segment will (substantially) lift (only) ITSELF (and a small amount of tons that, great part, is NOT extra-payload, but only 2nd stage mass...) WHY do they spend so much time and money to have (substantially) NOTHING ???

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