Do you (exactly) know how to "man-rate" a rocket?

gaetanomarano · 2006-05-06 19:13:20

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Over six months ago, I've suggested on a space-forum to build a little version of the CEV (not a 6-seats CEV, but a 4.5mt., 3/4-seats, bell-shaped, 18 tons max CEV/SM) and launch it with an already available rocket (with some changes and upgrade) like the Delta or Atlas or Ariane5 to save GIANT quantities of time and money (to build the CLV).

My proposal received many critics (like "CLV is the only way", etc.), but, month after month (especially after the problems of the CLV, the changes of its design, the cost-grow, etc.), I've seen many articles on space-websites and blogs and many threads/posts on space-forums with the same proposal.

Also, since I think that the VSE "one-and-half" launch architecture is very dangerous (as explained here: www.gaetanomarano.it/articles/004.html), a month ago I've suggested to use an SLV for the VSE moon missions.

But, every time I (and others) suggest to use another rocket (instead of the CLV), one or more forums' users find "THE BIG OBSTACLE": "man-rate the rocket".

I think that this problem don't exist (because also the CLV must be "man-rated"...)

However, I open this thread to know something more about rockets' "man-rating".

Do you have any info and/or links about "man-rating" procedures, times and costs?

If you have them, please post that info/links here, thank you.

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SpaceNut · 2006-05-06 19:50:42

Welcome gaetanomarano to NewMars. Interesting web site by the way.

The question of man rating can be found in the past as to what we have done first with the use of a Military Redstone to launch Mercury capsule and with the Titan to loft Gemini to orbit.

What were the changes Nasa need to make them safe for manned use or is it just that man has used it already for his flights?

The escape tower at the top of the capsule comes to mind to seperate the astronauts from the rest of the ship should the need arise for starters.

Article that basically does ask the same question within it but does not go onto explain.
September 4, 2005: The Pentagon had hoped NASA would buy into its heavy rocket program

Depending on the configuration needed to put payloads into orbit, EELV launch cost can range from $100 to $250 million. NASA would have had to spend lots of time and money "man-rating" an EELV configuration as safe for use in manned space flight.

Tried sales tactic;

Boeing is pitching it and a slightly smaller Delta IV Medium as primary launchers for NASA's new manned space exploration efforts. While not man-rated as yet, with its liquid-fueled design and new engineering Boeing is calling it "man-compatible", claiming the full rating should be relatively straightforward. They also point out that NASA could save a great deal of money on ground support because the Delta IV launch complex is already in place and fully functional.

Nasa's response

Of course, such a completely reasonable proposal will probably have zero chance with the "new new NEW NEW NEW!!!" attitudes NASA historically holds dear. The Astronaut Office in particular has already gone on record as stating "human rating should be designed in, not appended on." However, their problems seem to mostly center around the difficulty of "safing" the solid booster systems found on the smaller "medium" Delta and competing Atlas designs, which the all-liquid Heavy does not have.

GCNRevenger · 2006-05-07 00:00:56

I think I will have to invoke the concept that all the engineers at NASA can't be that stupid, so you must be wrong, gaetano.

The idea that the launch escape system is the cure-all and the rest of the rocket is irrelivent to man rating is nonsense, nothing could be further from the truth!

Just like a jet fighter, if something bad were to happen and you had to abort, you would need an ejection seat or whatnot to survive, but the seat alone does not determine if the plane itself is safe enough to fly in or not.

The launch escape system for instance will do you no good if it doesn't activate in time to save the crew: how does the system know when to activate? Is it possible to know far enough in advance confidantly at all? This is one of the main drawbacks of the EELVs, that it might be cheap enough to slap sensors on it, but figuring what sensor reading should trigger abort would be extremely expensive if practical at all. This problem is shared, to lesser extent perhaps, by the CaLV.

Then there is the issue of the surviveability of a particular failure mode: just blowing the capsule off the rocket does not ensure survival, and if the capsule cannot recover and land safely, then it doesn't matter does it? If the capsule is trapped in a hypersonic dive upside down or the crew is forced to land in the icey atlantic, then the escape system is useless.

And the biggest point of all, the abort system is for a last resort, it is extremely dangerous to use it at all, and should only be used if the danger of not using it is greater. If a rocket is too unreliable, then the rocket is not safe irrespective of its efficiency.

NASA's CLV has advantages in all of these traits, the main one however is the latter, that it uses the most reliable large rocket in the world, over 200 firings without a single mission-end failure when used within specification. The J-2 is also a very simple, reliable engine with a good track reccord and inate ability to re-ignite easily.

Being a simpler vehicle overall compared to the Delta, Atlas, or CaLV rockets with their multiple engines also means that escape system trigger mechanism will be much easier to deal with, and will increase safety.

TheStick also have a number of advantages with failure modes over any other proposed vehicle, the main advantage being that the big SRB does not explode. The booster is made from solid steel casing, and the fuel inside only burns rapidly when it is under high pressure... so if there is a leak, it will be small, and it will inherintly cause the engine to shut down. You can't beat that for safety, and you can seperate from the booster at a liesurely pace.

The J-2 has proven to shut down safely if it begins to fail on Apollo, and no other engine like it can lay a similar claim. It also is of a type that doesn't tend to blow up in a big way. No other engine can claim this, not even the SSME.

And thanks to the SRBs high thrust (and G-forces, which can be a good thing) and the J-2's low thrust, you might be close enough to orbit to burn your Earth-return fuel so you can avoid a dangerous hypersonic emergency reentry over the freezing Atlantic and instead have a whole orbit to land normally in California. No other rocket offers this advantage, including the CaLV.

This is in contrast to the engines on Atlas/Delta, the Delta's little SRBs have proven problematic in the past, and neither rocket can lift the CEV without using them except the big tripple-barrel. The Delta-IV heavy and the CaLV both use the RS-68, which is not a proven safe engine, and was infact designed to be cheap as possible.

I also want to comment on this idea that if a rocket is sufficently reliable, then it might as well be "man rated" too. This is also not the case, as Shuttle has shown us no practical rocket is safe enough without a working escape system, and for this system to work the escape system has to be carefully integrated and tested with the rocket. This is a big pro for building TheStick, because integrating this system with a new purpose-built rocket will be easy, and building the system into the big dumb cargo rocket will be hard, expensive, and unessesarry.

Apollo also proved very little, the big Saturn-V would probably not be acceptably safe if used today, because our risk tollerance was higher in the race to beat the Commies to the Moon. This is not the case today, especially after Columbia, Congress and the public will not readily tollerate a fatal failure on the "first leg" of the trip to the Moon or Mars.

GCNRevenger · 2006-05-07 00:43:25

Now, about this business of the "SLV"...

To condense what you have to say over several pages that are kind of rambling and hard to read, basically NASA's ESAS plan will fail because NASA can't launch TheStick within the month or two it takes for fuel to boil off from the waiting EDS/LSAM. The ideal window is one month from EDS/LSAM launch to departure, and most of the Moon is light for a few weeks at a time, so this works out nicely. Have both vehicles ready to go on their launch tables same time, launch the EDS, and have the astronauts ready to go as soon as its checked out on orbit. Or you could simply have more then one optional landing site if you are going exploring, And if we can't land at a Lunar base in the dark or launch the little CLV in a ~2mo window, then NASA is doomed anyway.

"Just image how many problems may happen in 2020 with two new rockets (shuttle derived...) and two new (and very complex) vehicles like the CEV and the LSAM made with thousands of parts and sensors!"

We don't have to imagine. It will have lots fewer problems, because the hyper-complex Shuttle won't be involved. Neither the LSAM nor the CEV nor any of the other ESAS plan components are even the same order of magnetude of complexity as Shuttle. The foam and fuel sensor problems you cite only occur because Shuttle is so fragile and poorly designed.

Overall I think you are wrong, because TheStick is such a simple rocket that its reduced complexity makes it less likly to be delayed. If ten times less complex as Shuttle, which I think possible, it will be ten times less likly to be delayed. Maybe more if its an exponential relationship.

In fact, the CLV will be the simplest launch vehicle of its class ever devised. The big workhorse booster has no surprises, and the J-2 is a fairly simple engine. And hey, only two engines on the launch vehicle! The service module will probably use the Shuttle OMS engines, which have proven extremely reliable too.

Besides the radically decreased complexity, by the time that the Moon rolls around, NASA will have been flying the CEV on TheStick around 20 times to the ISS. This experience plus the simplicity of the rocket - simpler then any other large rocket, even Russian ones, means that this shouldn't be a problem.

One of the main expenses associated with getting back to the Moon is the cost of developing the CaLV. The smaller it is, the sooner we go back, and adding an additional pair of solid rocket boosters not only will not increase the payload enough, but require much more extensive development and reduce reliability. It would also greatly increase the difficulty of man-rating the thing.

The bennefit of the "1.5" launch scheme is that it permits you to launch the crew on the safest practical rocket (see above post), while giving you a total payload of 150MT on orbit. It might be possible to make the CaLV this powerful, but its already expensive in its current form, and this form would be impractical. One CLV and one CaLV will surely beat two slightly smaller CaLVs cost wise too. (3 SRBs, 2 J-2X, 5 RS-68 versus 4 SRBs, 2 J-2X, 8-10 RS-68 counting engines, and the tanks/assembly costs for two CaLVs would be way more expensive.)

NASA is also obliged by Congress not to abandon the ISS (yet) for whatever reason, so it lets NASA retain the ability to send crew or light cargo too. Unless someone above the NASA admin says so, NASA is required to have access to the ISS until ~2017 with the smallest practical gap between Shuttle and CEV.

One problem with adapting Lunar hardware for Mars is sizing of the launch vehicle, that the huge 150MT class CaLV still aren't big enough to send a mission in one shot, but cutting it down to a smaller size and using multiples of them would be harder then just taking the EDS stage off the present ESAS CaLV.

I am also strongly opposed to any mission plan that delivers less then 20MT to the Lunar surface in a cargo-only role, and three men to the Lunar surface isn't enough I don't think. Two teams of two men each is the most efficient configuration. Again, the ESAS plan is already modest enough as it is, cutting it down any more risks a pointless repeat of Apollo.
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I'd also like to add that your scarry jibbering about numbers is kind of dishonest, just like Bob Zubrin's scare numbers he slung around when trying to smear O'Keefe's Moon plan. This business about "100% safe" rockets is just silly too, the Saturn-V for instance was by no means safe. Or this nonsense about each Lunar sortie costing $8Bn, which is just silly as well.

I also don't think it has occured to you that your "Plan C" will require direct landing and return from the Lunar surface. This cannot be accomplished with even an Apollo sized capsule with a reasonable payload except with the big 125MT class launcher, and not at all with the bigger CEV capsule.

Oh, and it would also eliminate the possibility of an Apollo-13 style free return abort, unless you wanted to accept a big payload penalty.

gaetanomarano · 2006-05-07 08:38:19

Nasa's response
Of course, such a completely reasonable proposal will probably have zero chance with the "new new NEW NEW NEW!!!" attitudes NASA historically holds dear. The Astronaut Office in particular has already gone on record as stating "human rating should be designed in, not appended on." However, their problems seem to mostly center around the difficulty of "safing" the solid booster systems found on the smaller "medium" Delta and competing Atlas designs, which the all-liquid Heavy does not have.

I don't understand why common people like us MUST BE rational in our choices while governments, companies, space agencies, etc. (of all countries) can be unrational and make lots of absurd things!

Each ton launched in orbit is extremely expensive, so, rationality is much more essential in space industries than others.

Another thing I say from 6+ months is that, build a 6-seats-CEV, despite ALL moon missions will be with 4 astronauts (because the LSAM will have 4-seats) and ALL orbital missions will be with 3/4 astronauts (NASA claim), mean a 33% of unused (but costly!) "dead weight" at every CEV launch.

And also the SM will be one model, despite an ISS mission (including ISS' orbital adjust) will need only 20% of the fuel of a moon mission (then, may be sufficient an SM "light").

Russia and China launch 3 astronauts in orbit with an 8-tons vehicle.

With to-day's technology and light material, an orbital-CEV/SM for 4 astronauts may weight 10 tons and a lunar-CEV/SM (due to the extra-fuel) less than 18 tons that, both, can be launched with ready available rockets!

Don't forget that, 8+ tons of CEV/SM "dead weight" will need 10-15 tons of extra EDS' weight and a 125-tons' payload CaLV instead of a simpler, and cheaper 100 tons' payload CaLV (that may use the ready available, reliable and cheaper 4-segments SRB).

These unrational choices mean a giant waste of time and money.

The first CEV will be launched in 2012 (but add 2+ years of delays), when the CLV will be available, while, an orbital-CEV-light launched with a Delta or Atlas or Ariane5 (and NOT the big and expensive "heavy" models) my leave the earth in 2010!

But the most absurd aspect is the COST of of the CLV.

Since it will launch 25 tons, it's "hardware costs" will be (minimum) 50% more than a 16 tons launcher.

The (planned) R&D costs of the CLV was $5 billion (NASA claim) now increased to $7 billion due to the extra R&D costs of the 5-segments SRB, costs that may reach the (very optimistic) figure of $10 billion when the CLV will fly!

Well, with the same R&D costs of the CLV (that must be made ONLY to launch the extra "dead weight" of the CEV) NASA can buy NOW up to 50 (fifty!!!!!!!!!!!!!!!!) Atlas/Delta/Ariane and launch 50 (fifty!!!!!!!!!!!!!!!!) more CEVs from 2010 instead of only a few from 2015+!!!

My true impressions is that NASA motto is not "new new NEW NEW NEW!!!" but "spend spend SPEND SPEND SPEND!!!" (twice the time and the money than necessary...)

However, I insist that the CEV must be made only for lunar missions and launched with the SLV and that an orbital-CEV (launched with CLV or other rockets) is completely unnecessary since, for ISS, will be an INCREDIBLE choice of cargo and crew vehicles: Digital-Soyuz, Kliper, Progress, ATV, the japanese cargo and (I'm sure) the ISS' cargo and crew versions of the Shenzhou.

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gaetanomarano · 2006-05-07 09:33:06

"I think I will have to invoke the concept that all the engineers at NASA can't be that stupid, so you must be wrong, gaetano."

No, they are NOT stupid, but, since they are "humans" like us, can make mistakes.

Six months ago in an interview Griffin defined both ISS and Shuttle "giant mistakes"... well, if that is true (like hundreds of space experts and forums' users say every day) means that thousands NASA engineers, scientists and officials have (repeatedly) made lots of mistakes for 30+ years!

And look also at the VSE/ESAS plan... two years of preparation after Bush's announcement, three months of study of the best NASA engineeers, then, after publishing the "final" and DETAILED plan in the december, EVERY DAY (from the first week after its publishing!) there are one or more little and BIG changes to the plan!

My question is: "how have they used the last two years, if the ESAS plan loses water from every hole?"

The answer is that NASA engineers are excellent but "humans", then, can make "mistakes", like everyone of us... and the next GIANT and INCREDIBLE mistake they are doing is the "one-and-half" launch architecture!

"The idea that the launch escape system is the cure-all and the rest of the rocket is irrelivent to man rating is nonsense, nothing could be further from the truth!"

right

despite the CEV will have the LAS, the rocket to launch it (CLV or SLV) must be made as good and reliable as possible!

"The launch escape system for instance will do you no good if it doesn't activate in time to save the crew: how does the system know when to activate?"

true

but that means no rocket is 100% safe, not even the CLV!

also, I think that an SLV is safer than a CLV or an EELV because the main risk of a launch is at lift-off when the rockets is a giant bomb of fuel

well, with an SLV the astronauts will be over 350 ft. away from engines' FIRE and fuel's tank, then they will have much more time to activate the LAS and much more probabilities to save their life!!!

"NASA's CLV has advantages in all of these traits"

not true

if you use an old engine in a completely new car don't mean that the car is reliable

the new SRB will be completely different and made to work alone (without Shuttles' energy and controls), the J2X will be a new version and the entire "system" (SRB, interstage, J2X, tanks, SM, CEV, LAS, software, etc.) will be completely new and never used before, then, experimental

only after 15+ test/unmanned/manned flights we can know if (and how much) the new rocket is reliable

Delta, Atlas and Ariane are more complex but they have already made dozens of successful launches (and are well known in all their aspects)

"...so if there is a leak, it will be small, and it will inherintly cause the engine to shut down..."

...and will falls on itself from 1, 10, 30+ km... that (I think) is NOT so safe for the astronauts!

"you might be close enough to orbit to burn your Earth-return fuel so you can avoid a dangerous hypersonic emergency reentry over the freezing Atlantic and instead have a whole orbit to land normally in California"

...but only if the SRB's failure will happen at high altitude... then, the problem is only if the astronauts will be lucky or not

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GCNRevenger · 2006-05-07 09:49:36

Again, you are simply wrong... lets see here:

First, the CEV is sized to hold four men for long periods, but six is only for a short time. Let me say that again, that the six-seat condition would only be used for short periods, like one day tops. The trip to the Moon will require the crew to spend two or three weeks in the capsule. The only time six seats would be used would be for emergency return from the ISS or Earth return following a Mars mission. Again, the CEV will primarily be a four-seater, and it is sized as such, with the six-seat mode only being for short times. Its not dead weight, Apollo was really a bit too small for three men to spend two weeks in, and I think the CEV is about the right size.

"Each tonne launched into orbit" is irrelivent when you are talking manned vehicles versus satellites or bulk cargo. The only question is can the rocket carry out the mission? It costs nearly nothing for the CLV to launch ~25MT compared to 20MT, and adding a few feet or another cheap $15M RS-68 engine to the CaLV tanks costs nearly nothing as well. And "...it's "hardware costs" will be (minimum) 50% more than a 16 tons launcher" is also a fallacy, because it won't cost any more to make the 25MT CLV then the 20MT. Infact, it might cost less over all. Your complaining is just like the irrational Mark Wade, bemoning tonnes just because "a big number is bad." This likewise applies to the CEV for use as an ISS transport, that it won't cost any more to launch the service module tanks full as it would empty, so why not? The fuel could be burned to re-boost the station so the Russian Progress and ESA ATV could carry more cargo.

Or, perhaps even more importantly, in reference to my above post about man-rating the extra fuel in the CEV-SM will give an extra "safety net" to boost them into orbit should the CLV fail. This is important, because launching to the ISS takes the vehicle over the freezing cold North Atlantic ocean, where survival chances are slim. Also, current vehicles departing from the ISS take a few days for their orbit to allign over the desired landing site, but if you have an injured crewman or the capsule was damaged in an ISS accident, then the extra fuel could be burned to get you back down to a safer landing site quickly. The cargo-only CEV can also haul much more payload if it trades that fuel for mass. The added fuel that a fully loaded service module has is a tremendous advantage and costs NASA nothing!

Comparing the CEV to Soyuz or Shenzou is nonsense, because the CEV isn't intended to do the same thing. If you were to put Earth-return fuel on either of the foreign capsules, they would weigh ~15MT at least I would imagine. The Soyuz is really only a two-man capsule, modified to cram a third man in. The CEV will hold four for much longer times, and six in the "return only" role. The CEV will also be more reuseable then these capsules, because Soyuz and Shenzou both disguard their orbital module as well as their service module. NASA does intend to reuse the CEV capsules you know, at least from gentler ISS trips, which will overall save money versus these three-piece capsules despite being heavier.

You also make big talk about "light material" making a rather large difference in the CEV's mass. This is not going to happen, because the materials available aren't that much lighter then regular materials. They are also more difficult to use, since carbon composites or ultralight aluminum alloys don't withstand high temperatures very well. The CEV service module structure and tanks will likly be made from carbon composite however.

Again, while it might be possible to modify the medium Delta or Atlas rockets to carry a down-graded three seat or a cramped multi-module four seat capsule, but doing so would be very difficult. These large liquid rockets with engines designed to be cheap not reliable should not be much easier then to build the CLV. Only the heaviest configuration of either launcher would suffice, which means four of those little flimsy problem-prone solid rocket motors too, while the CLV will have only two of the safest engines of their class available. It will be easier to build and man-rate the CLV then it would to man-rate the EELVs.

The increased cost of the CLV due to the inclusion of the five-segment booster is also a fallacy, because this cost would have simply been incured later when we start building the CaLV anyway. Pay it now or pay it later, we would eventually have to pay. Paying it now permits us to abandon the four-segment SRB production line and to abandon the expensive SSME, both of which would have reoccuring costs that now NASA won't have to pay.

And what is with the exclamation marks? So what if NASA could launch the dinky little EELVs lots of times, where would it fly them to? The worthless ISS? If you average their payload masses, they only add up to ~800MT, which can be lifted by just six of the big CaLVs.

Whatever any of us thinks about the ISS is unfortunatly irrelivent, that barring as serious station accident or the loss of another Shuttle, NASA is obliged by treaty and legeslation to support and have access to the ISS for some time, so it doesn't matter a bit if other countries could perform these duties instead.

The only person concerned with your triade who aren't being rational is you, gaetano, not NASA. These choices, with exception to ISS duty perhaps, are perfectly rational, and the greater capability and safety of the ESAS plan comes at a negligible additional cost. NASA needs this new hardware, and the only thing not NEW NEW NEW!!! in your babbling is the EELVs, which using them instead of the CLV won't save much money if any.

Rxke · 2006-05-07 09:51:45

Dude...

I was willing to lend an ear but you blew it big time in the last post...

well, with an SLV the astronauts will be over 350 ft. away from engines' FIRE and fuel's tank, then they will have much more time to activate the LAS and much more probabilities to save their life!!!

If stuff goes seriously haywire, it means little if you're 350ft away or 10, I mean explosive stuff... That's FAST. If it's minor, a couple of hundreds of feet doesn't make much difference either.

And then:

...and will falls on itself from 1, 10, 30+ km... that (I think) is NOT so safe for the astronauts!

rockets don't go straight upwards. I knew that when I was six.

You lost a lot of credibility with that assertion.

gaetanomarano · 2006-05-07 10:04:07

Dude...
I was willing to lend an ear but you blew it big time in the last post...
well, with an SLV the astronauts will be over 350 ft. away from engines' FIRE and fuel's tank, then they will have much more time to activate the LAS and much more probabilities to save their life!!!
If stuff goes seriously haywire, it means little if you're 350ft away or 10, I mean explosive stuff... That's FAST. If it's minor, a couple of hundreds of feet doesn't make much difference either.
And then:
...and will falls on itself from 1, 10, 30+ km... that (I think) is NOT so safe for the astronauts!
rockets don't go straight upwards. I knew that when I was six.
You lost a lot of credibility with that assertion.

about "explosive"...

the life of the astronauts will be 99.999% in the LAS' hands because also part of the CLV (2nd stage and SM) will have engines and fuels that may explode

about "credibility"...

since I don't make personal comments on you, please, don't make personal comment on me

if you think that I'm wrong simply post your opinion, thank you

about "rocket falls"...

after engines' stop the rocket will (of course) continue to fly due to inertia, but, when that inertia ends, it will falls down due to "earth gravity" (that probably you know from when you was five...)

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GCNRevenger · 2006-05-07 10:35:00

"No, they are NOT stupid, but, since they are "humans" like us, can make mistakes. " Symantic back-tracking. Your statements clearly indicate you think the NASA plan is terrible and totally unworkable. So either they are right or you are right, and my money is on NASA.

The Shuttle and ISS were mistakes, but they were mistakes based on the desire to maintain the political status quo, and were not the product of engineering decisions. The ESAS plan is largely founded on engineering, so either the engineers are right or they are wrong, Shuttle and the ISS were a different kind of mistake.

"And look also at the VSE/ESAS plan... two years of preparation after Bush's announcement, three months of study of the best NASA engineeers... EVERY DAY there are one or more little and BIG changes to the plan!"

Well yes, I sure hope they do. So far, all the changes have pretty much been positive. Get rid of the four-segment SRB, get rid of the SSME, get rid of Marshall SFS's incompetantly-managed Methane engine, and build a safer CLV and cheaper CaLV to boot. NASA must not rush, beause their political capital is so scarce. NASA made similar trade studies and changes with Apollo too you know, and it seemed to work out pretty well.

"the ESAS plan loses water from every hole"

Really? How?

"despite the CEV will have the LAS, the rocket to launch it (CLV or SLV) must be made as good and reliable as possible!"

Thats correct. Any use whatsoever of the escape system is extremely risky, just like using an ejection seat on a fighter plane. It is not something to be done willingly or lightly, and no fighter pilot would ever use it unless it meant certain death. Your chances of injury or death are pretty high if the system is used, so if the risk of needing the escape system is high, then the launch vehicle is not reliable enough. Because it would be so hard to make a system that minimize the risk of the escape system and maximize the reliability of the EELV/EELV-derived CaLV, NASA's CLV and the 1.5 launch arcitecture makes perfect sense.

"I think that an SLV is safer than a CLV or an EELV because the main risk of a launch is at lift-off when the rockets is a giant bomb of fuel"

This makes no sense. The LSAM/EDS will burn Hydrogen fuel just like the CLV's upper stage, and the CLV will be just as tall as the CaLV, so you won't be any further from danger anyway. One of the most dangerous things is getting enough altitude to open the parachutes, which n this the CLV's rapid acceleration is superior to the CaLV or EELV.

"if you use an old engine in a completely new car don't mean that the car is reliable"

Your analogy is stupid. There is no charitable way to put it otherwise, just calling it silly would be too inadequete. The big SRB is the safest engine of its size ever built, bar none. Its made of solid steel plate instead of flimsy aluminum sheet, it stops burning instead of blowing up, and has a long proven track reccord. Likewise, the J-2 is not likly to blow up like the high-pressure SSME, is the only other cryogenic engine ever used for a manned space vehicle, and its safety shut-down has been proven several times.

It is true that the "new" engines will not be just like the old SRB or J-2, but they will be built the same way and will share their unmatched safety. The five-segment SRB's new fuel will burn even more benignly, and the new varient of the J-2 will be made with even safer materials. They won't be the old tried and tested engines, but neither will they be "new and experimental" either.

Contrast this to the main engine of the CaLV, the RS-68: the RS-68 was designed first and foremost to be just one thing, CHEAP. The RS-68 has no good emergency shutdown modes, since its parent rocket (Delta-IV) doesn't need them. It is not built for high reliability like the made-for-man J-2, and would require more serious modification then the J-2 to make it practical for manned flight.

"only after 15+ test/unmanned/manned flights we can know if (and how much) the new rocket is reliable.

Well, then NASA made a huge mistake flying the Saturn-V with a human crew after only two partially failed test flights, didn't they? You picked the "15+" number out of thin air, ground testing of the components will be sufficent to minimize the number of test flights.

"...and will falls on itself from 1, 10, 30+ km... that (I think) is NOT so safe for the astronauts!"

Like Rxke said, this isn't a problem. Infact, the sudden loss of thrust means that the escape system doesn't need to be quite as violent like it would on an EELV, because liquid engines tend to blow up if they leak, requiring a very violent escape mechanism.

"...but only if the SRB's failure will happen at high altitude... then, the problem is only if the astronauts will be lucky or not"

No, even if the big SRB fails shortly after liftoff, the J-2 upper stage would have enough fuel to boost the CEV suborbital over the Atlantic most likly. Anyway, the burn time of the SRB is short compared to the EELV or CaLV, so this is actually a smaller risk then these "slower" rockets.

GCNRevenger · 2006-05-07 10:50:33

about "explosive"...
the life of the astronauts will be 99.999% in the LAS' hands because also part of the CLV (2nd stage and SM) will have engines and fuels that may explode
about "credibility"...
since I don't make personal comments on you, please, don't make personal comment on me
if you think that I'm wrong simply post your opinion, thank you
about "rocket falls"...
after engines' stop the rocket will (of course) continue to fly due to inertia, but, when that inertia ends, it will falls down due to "earth gravity" (that probably you know from when you was five...)

No, 99.999% is an absurd figure. There is always a chance that the whole rocket will blow up and kill the whole crew before the escape system has a chance to activate. There is a chance that the escape system itself will fail and the crew will die. There is a chance that the crew will be killed by the extreme G-forces generated by the escape system. There is a chance the escape system will plop the crew down in the middle of the North Atlantic and they will freeze to death before rescue. Perhaps it will drop you in a hypersonic dive or spin that you can't recover from. Or maybe it will just plop you upside down so your can't open your parachutes.

Etcetera etcetera... the escape system is the option of last resort, NEVER the first, and the first being that the rocket works and nothing bad happens at all. Reliability is absolutely crucial, and the CLV can provide this better then either EELV or CaLV.

And if there is a failure, the CLV offers better abort options then firing the escape system and praying that you don't die, the if the booster leaks it shuts down, then the J-2 and service module can carry you across the ocean to safety. Or if the J-2 shuts down, the service module fuel can do the same thanks to the speed from the big booster. In neither case would you have to "pull the trigger" and fire the escape system.

The lower reliability of the big CaLV or the EELVs with its eight engines or their 6-8 cheap failure-prone satellite launcher engines is compounded with the fact that they don't have these above "softer" failure modes for very long during acent, since they accelerate more slowly.

And you do know how rockets launch, right? They remain nearly vertical after liftoff only a short while, just long enough to get above the thickest part of the atmosphere, then roll over sharply and fly almost horizontally over the Atlantic. So where you fall is a big issue.

gaetanomarano · 2006-05-07 11:19:30

First, the CEV is sized to hold four men for long periods, but six is [i]only for a short time. Let me say that again, that the six-seat condition would only be used for short periods, like one day tops. The trip to the Moon will require the crew to spend two or three weeks in the capsule. The only time six seats would be used would be for emergency return from the ISS or Earth return following a Mars mission. Again, the CEV will primarily be a four-seater, and it is sized as such, with the six-seat mode only being for short times. Its not dead weight, Apollo was really a bit too small for three men to spend two weeks in, and I think the CEV is about the right size.[/i]

The six-seats-CEV is unnecessary for ISS rescue and Mars travel (if and when will happen...) because can be simply used TWO capsules (like to-day's Soyuzs) docked to two ports (that have two more advantages: up to eight seats and the opportunity to save minimum half crew if one capsule will fails)

In the new moon missions the astronauts will use the CEV only for THREE days (when they will come back to earth) because in the earth-moon travel they can live in the GIANT lunar module that will have 5+ times the volume than an old-LEM, then, a 4.5 mt., "bell-sized" (with 70% more volume of the Apollo CM) and two SM ("full" and "light") launched with ready available rockets may do both job fine.

[i] "Each tonne launched into orbit"[color=violet] is irrelivent when you are talking manned vehicles versus satellites or bulk cargo. The only question is can the rocket carry out the mission? It costs nearly nothing for the CLV to launch ~25MT compared to 20MT, and adding a few feet or another cheap $15M RS-68 engine to the CaLV tanks costs nearly nothing as well. And "...it's "hardware costs" will be (minimum) 50% more than a 16 tons launcher" is also a fallacy, because it won't cost any more to make the 25MT CLV then the 20MT. Infact, it might cost less over all. Your complaining is just like the irrational Mark Wade, bemoning tonnes just because "a big number is bad." This likewise applies to the CEV for use as an ISS transport, that it won't cost any more to launch the service module tanks full as it would empty, so why not? The fuel could be burned to re-boost the station so the Russian Progress and ESA ATV could carry more cargo. [/color][/i]

The costs counts if the extra-tons sent without any reasons are many.

true, a 20-tons-CLV may cost like a 25-tons-CLV... but I suggest to don't build any CLV but use other rockets

the costs of a CLV and an Atlas/Delta was comparable with the first version of CLV (with ready available SRB and SSME) but not with the new version that may cost 30-50% more than to-day's rockets

I've read the Mark Wade's blog, but I've made the same considerations months before on a space-forums

a bigger SM will weight more due to its own structure, not only the fuel and, if you compare the fuel weight of a Soyuz vs. the CEV, you see that the CEV's fuel is too much also if it need to re-boost the ISS

I think that facts wins on words... the fact that an old and little Soyuz/Progress do the job of support the ISS from years clearly demontrates that a bigger capsule may be good but not absolutely necessary

the extra fuel could be burned to get you back down to a safer landing site quickly. The cargo-only CEV can also haul much more payload if it trades that fuel for mass. The added fuel that a fully loaded service module has is a tremendous advantage and costs NASA nothing!

you're right, but the "extra-fuel" we are talking about is too much since it will need to leave the lunar orbit

I think that a cargo-CEV will NEVER be used because its launch cost (CLV+cargoCEV) will be 10+ times the cost of the Progress, ATV, etc. (and NASA/ESA don't have money to burn)

true... the "added fuel" don't cost nothing... unfortunately, send in orbit that extra-fuel (that in 90% of non-rescue and non-reboost missions will be NOT used) will need a bigger rocket... that costs!

Comparing the CEV to Soyuz or Shenzou is nonsense, because the CEV isn't intended to do the same thing. If you were to put Earth-return fuel on either of the foreign capsules, they would weigh ~15MT at least I would imagine. The Soyuz is really only a two-man capsule, modified to cram a third man in. The CEV will hold four for much longer times, and six in the "return only" role. The CEV will also be more reuseable then these capsules, because Soyuz and Shenzou both disguard their orbital module as well as their service module. NASA does intend to reuse the CEV capsules you know, at least from gentler ISS trips, which will overall save money versus these three-piece capsules despite being heavier.

true... the CEV can't be compared with a Soyuz, the CEV is bigger, with 4 astronauts, more fuel, etc. because it is designed for moon missions, in fact, I suggest to use it ONLY for the moon missions (with the SLV) and use the Soyuz, etc. for the ISS (this is not only my opinion since NASA buys Soyuz and Progress every years...)

You also make big talk about "light material" making a rather large difference in the CEV's mass. This is not going to happen, because the materials available aren't that much lighter then regular materials. They are also more difficult to use, since carbon composites or ultralight aluminum alloys don't withstand high temperatures very well. The CEV service module structure and tanks will likly be made from carbon composite however.

it's 50% true because some materials will be similar to the Apollo but great part of internal devices and materials will be 2 to 10 times lighter and smaller than Apollo (computers, electronics, panels, displays, spacesuits, etc.)

Again, while it might be possible to modify the medium Delta or Atlas rockets to carry a down-graded three seat or a cramped multi-module four seat capsule, but doing so would be very difficult. These large liquid rockets with engines designed to be cheap not reliable should not be much easier then to build the CLV. Only the heaviest configuration of either launcher would suffice, which means four of those little flimsy problem-prone solid rocket motors too, while the CLV will have only two of the safest engines of their class available. It will be easier to build and man-rate the CLV then it would to man-rate the EELVs.

you forget that this is the way ALL past (Apollo, etc.), to-day's (Soyuz, etc.) and future capsules have (reliably) made 150+ succesful flights... CLV will be completely new and its REAL advantages and reliability will be known only when (and IF...) will really fly...

The increased cost of the CLV due to the inclusion of the five-segment booster is also a fallacy, because this cost would have simply been incured later when we start building the CaLV anyway. Pay it now or pay it later, we would eventually have to pay. Paying it now permits us to abandon the four-segment SRB production line and to abandon the expensive SSME, both of which would have reoccuring costs that now NASA won't have to pay.

true, but (as I explain in my article) I suggest to build a 150-tons SLV with three 4-seg. SRB or a 120-tons SLV (with resized CEV, LSAM, etc.) with two 4-seg. SRB and NEVER build the 5-seg. SRB saving $2 billion of R&D, 2-3 years of time and $30+ million per SRB

And what is with the exclamation marks? So what if NASA could launch the dinky little EELVs lots of times, where would it fly them to? The worthless ISS? If you average their payload masses, they only add up to ~800MT, which can be lifted by just six of the big CaLVs.

you're right, in fact in my article (and here) I don't suggest to send 50 missions to the ISS but to use the GIANT quantity of (R&D+hardware) money saved to make 20+ moon missions (instead of only 12 missions) from 2015 to 2020 (instead of 2020-2025)

Whatever any of us thinks about the ISS is unfortunatly irrelivent, that barring as serious station accident or the loss of another Shuttle, NASA is obliged by treaty and legeslation to support and have access to the ISS for some time, so it doesn't matter a bit if other countries could perform these duties instead.

not true, this is a matter of politics, then, if the Shuttle is too dangerous and the CEV too expensive for ISS' missions, politics MUST change their decisions (and NASA/ESA will do the job in adifferent way)

The only person concerned with your triade who aren't being rational is you, gaetano, not NASA. These choices, with exception to ISS duty perhaps, are perfectly rational, and the greater capability and safety of the ESAS plan comes at a negligible additional cost. NASA needs this new hardware, and the only thing not [i]NEW NEW NEW!!! in your babbling is the EELVs, which using them instead of the CLV won't save much money if any. [/i]

I can say you a dozen of "opinion" I've written on my articles and/or posted on space-forums that are the same of recent NASA decisions and changes... I think that SLV will be one of the next...

.

gaetanomarano · 2006-05-07 13:50:01

No, 99.999% is an absurd figure. There is always a chance that the whole rocket will blow up and kill the whole crew before the escape system has a chance to activate. There is a chance that the escape system itself will fail and the crew will die. There is a chance that the crew will be killed by the extreme G-forces generated by the escape system. There is a chance the escape system will plop the crew down in the middle of the North Atlantic and they will freeze to death before rescue. Perhaps it will drop you in a hypersonic dive or spin that you can't recover from. Or maybe it will just plop you upside down so your can't open your parachutes.

true, but it must be close to about 99%

also the risks of the LAS itself are true, in fact the CEV/CLV can't be "10 times safer" than Shuttles (NASA claim) but probably will have the same risk (we can know the real figure and compare it only when the CEV will fly 114+ times)

Etcetera etcetera... the escape system is the option of last resort, NEVER the first, and the first being that the rocket works and nothing bad happens at all. Reliability is absolutely crucial, and the CLV can provide this better then either EELV or CaLV.

true, but, unfortunately, with a capsule this is the only way to save the astronauts' life if something goes wrong

And if there is a failure, the CLV offers better abort options then firing the escape system and praying that you don't die, the if the booster leaks it shuts down, then the J-2 and service module can carry you across the ocean to safety. Or if the J-2 shuts down, the service module fuel can do the same thanks to the speed from the big booster. In neither case would you have to "pull the trigger" and fire the escape system.

not true, this is only an (undemonstrated) myth

when the CLV will fly we can see how much it is (really) reliable

don't forget that it must have a 114/2 safe rate to be safe like the Shuttle and the Soyuz...

the realty is that both rockets will have risky and safe moments in their flights

The lower reliability of the big CaLV or the EELVs with its eight engines or their 6-8 cheap failure-prone satellite launcher engines is compounded with the fact that they don't have these above "softer" failure modes for very long during acent, since they accelerate more slowly.

lower reliability....

absolutely not true

all (multi-engines) manned SaturnV flights was successful and the CaLV is very close to the Shuttles at lift-off (the CaLV will have only one-two SSME/RS68 more than Shuttle)

the (multi-engines) Shuttles have made 113 successful lift-offs, and the ONLY Shuttles' failure at lift-off was due to an SRB fault!!!

I think that the solid-fuel-single-SRB/firecracker-CLV may be very dangerous... but we must wait to have all answers to our doubts

the multi-engines rockets (with thrust redundancy) are safer and more reliable than single engines because, if one engine fails (like the SaturnV 2nd stage in the Apollo13 mission) the other rockets' thrust can do the full job!

This is the main reason that the old Soyuz is so reliable (with its ultra-multi-engines 1st stage)

And you do know how rockets launch, right? They remain nearly vertical after liftoff only a short while, just long enough to get above the thickest part of the atmosphere, then roll over sharply and fly almost horizontally over the Atlantic. So where you fall is a big issue.

I know it, of course... "falls on itself" is like "come back to earth" or "crash" (english is not my mother language)

.

Rxke · 2006-05-07 14:03:36

about "credibility"...
since I don't make personal comments on you, please, don't make personal comment on me
if you think that I'm wrong simply post your opinion, thank you.

Huh?

I'm just saying you base your reasoning on something flatly wrong, so I say you lose cre...

Oh, I get it.

Wasn't meant as a personal attack, that's just my 'wording' (I'm Dutch) I left out the explicit 'your reasoning' bit, I guess.. :?

let me rephrase that: your reasoning lost a lot of credibility.

I mean, you use reasons that aren't reasons -because they don't take into account the *very basics* of launch envelopes- to make a point how dangerous the approach is.

gaetanomarano · 2006-05-07 14:25:08

NASA plan is terrible and totally unworkable

no, NASA plans may simply have mistakes, like all "plans"

The Shuttle and ISS were mistakes, but they were mistakes based on the desire to maintain the political status quo, and were not the product of engineering decisions. The ESAS plan is largely founded on engineering, so either the engineers are right or they are wrong, Shuttle and the ISS were a different kind of mistake.

I don't agree

the Shuttles and ISS was not only a "political mistake" but (most) an engineering mistake: its LEGO-like design, all modules different without any standardization (to reduce costs), Shuttle-based assembly (without any cheaper alternative), its orbit inclination, etc. (and about the Shuttle... side-mounting, cargo-and-crew launch, no escape mode, etc.)

Really? How?

see the changes alerady made and those that will happen in the next 10 years...

This makes no sense. The LSAM/EDS will burn Hydrogen fuel just like the CLV's upper stage, and the CLV will be just as tall as the CaLV, so you won't be any further from danger anyway. One of the most dangerous things is getting enough altitude to open the parachutes, which n this the CLV's rapid acceleration is superior to the CaLV or EELV.

true, but the lift-off (with so much fire and the tanks full of fuel) is very dangerous

Your analogy is stupid.

please avoid personal opinions about me, thank you

The big SRB is the safest engine of its size ever built, bar none.

to-day's SRB is safe but CLV's SRB will be different and the entire CLV/SM/CEV system will be very complex

we must know the (real) reliability of the entire system, not only part of it, and the full system will be "new and experimental" because there are thousands of (big and little) parts that may work or not

a new car my be perfect but the accident may happen due to a defective wheel

The RS-68 has no good emergency shutdown modes

I hope that NASA will use the SSME

You picked the "15+" number out of thin air

I say "15" but may be 10 or 20, it's a problem of statistics, with only two successful launches (or fails) we can't say that a rocket is 100% safe (or unsafe)

we need 10, 15, 20 or more flights to have REAL statistics of its reliability (and we need 250+ successful flights to claim that the new CLV is "safer" than Shuttle+Soyuz...)

No, even if the big SRB fails shortly after liftoff, the J-2 upper stage would have enough fuel to boost the CEV suborbital over the Atlantic most likly. Anyway, the burn time of the SRB is short compared to the EELV or CaLV, so this is actually a smaller risk then these "slower" rockets.

true, but only if the altitude is sufficient, if the failure is not too fast, if all works well, etc.

.

gaetanomarano · 2006-05-07 14:32:56

about "credibility"...
since I don't make personal comments on you, please, don't make personal comment on me
if you think that I'm wrong simply post your opinion, thank you.
Huh?
I'm just saying you base your reasoning on something flatly wrong, so I say you lose cre...
Oh, I get it.
Wasn't meant as a personal attack, that's just my 'wording' (I'm Dutch) I left out the explicit 'your reasoning' bit, I guess.. :?
let me rephrase that: your reasoning lost a lot of credibility.
I mean, you use reasons that aren't reasons -because they don't take into account the *very basics* of launch envelopes- to make a point how dangerous the approach is.

you are dutch and I'm italian so, talk in another language, may be a problem

the lack of "basic" don't exist if I translate in the wrong way what I think (and you understand it in a further way...)

if (simply) you post your opinion, I can refine my post to explain that "falls on itself" don't is "literally" but means only that it "come back to earth" etc. etc. etc.

.

Rxke · 2006-05-07 15:59:38

Yes, I saw you clarified that in a further post (the falling on itself) so no reason to go further into it. Point taken (I think)

Misunderstandings happen, esp. on discussionboards.

By the way: heehee, I'm Belgian, not Dutch, but I speak Dutch, another sloppy way of writing from my side :oops:

gaetanomarano · 2006-05-07 16:30:11

Misunderstandings happen, esp. on discussionboards.

Internet (sci-fi only 15 years ago!) is so useful and interesting that, a few misunderstandings on discussion boards, is a very little problem if compared with the opportunity to talk of our ideas and interests with the entire world!

.

Rxke · 2006-05-07 16:49:37

Yeah, I still sit back in awe, every single day.

Been using computers for about 20 yrs, saw it coming, but never thought virtually everybody (in the 'rich world') would become a computer-user, grin. Always thought it would something seen as 'uncool' by tmost people.
How times have changed.

SpaceNut · 2006-05-07 20:20:46

The idea that the launch escape system is the cure-all and the rest of the rocket is irrelevant to man rating is nonsense, nothing could be further from the truth!

Actually I wanted to start slow and try to show why each piece has significance.

A tower is the only means while still in flight to remove the crew from harm while main engines are still firing since the stage engines that push the capsule can not. I agree that it is a last ditch effort for crew to survive and that the parachute system must work correctly as well as the means for landing.

As for slapping sensor on the EELV's, not knowing where they are needed and for why does little good. There is also little good from these sensors if they are not processed in real time for use by the crews flight control. One of the reasons for shuttle being doomed twice in that devices to store data from sensors where integrated but not sent to the crews controls panels.

Yes each engine must be very durable and able to survive the extremes of use with its particular stage able to separate from the others and in a controlled process be detonated to lessen chances of it striking what remains.

A valid question is if the RS-68 where to be used on a manned ship what would it take to make it so? Who should bare the cost of its modifications, development or redesign? This is also a problem of the SSME for it was designed for starting while on the surface and not at the approximate 25 miles up that it would need to be able to do and that does not count firing it for multiple ignitions as needed.

Now engines are only one of the problems for man rating since it is indirectly the result of the fuel that it is going to use for a give stage in its design.

Now lets get back to the capsule seating size while 4 is plenty for the moon and 6 is great for LEO to the ISS, neither quantity effects the capsule very much at all as the weight would end up being. It mainly alters the size of the support module with what would be the 3rd stage. It is the staying time while in use that makes this stage grow in size. There has been little mentioned as to what this stage will use for its engine but it will not be possible to determine until Nasa finally decides that one favor can not fit all uses.

GCNRevenger · 2006-05-08 05:57:42

"Mars travel... can be simply used TWO capsules"

I don't think you have a very good grasp of the concepts of reliability or spacecraft efficiency, gaetano. Two seperate capsules have twice the chance of failure, and two smaller vehicles of half the volume of a larger one will combined weigh far more then larger one. Besides, the Moon program should have four crew, and no fewer. The ISS will eventually have its six-man crew probably too, because Russia is preparing a second Zarya module to extend the life and add three more beds to the station. The US will still be obliged by treaty to provide emergency return for them, which mandates a six-seat capsule too.

The original Apollo capsule and Lunar lander were really too small to work in, with both of them being "standing room only." The CEV capsule and LSAM must not simply be bigger, but much bigger, since the crew will be staying on the Moon much longer and will need science space "indoors" unlike Apollo. Also, should any of the crew stay in orbit like the original Apollo missions, the CEV capsule alone must accomodate them for the duration.

For instance, the capsule has to be big enough to put on a full-sized modern space suit, which are considerably bulkier then today's Shuttle pressure suit or the Apollo tetherd suits. And you have to have room to put the things. Raw volume figures, cubic meters and whatnot, are completly irrelivent. The dimensions of the capsule are what is important, that it has to be big enough on every dimension to work in.

"The costs counts if the extra-tons sent without any reasons are many.

true, a 20-tons-CLV may cost like a 25-tons-CLV"

Your statements are contradictory

"the costs of a CLV and an Atlas/Delta was comparable with the first version of CLV (with ready available SRB and SSME) but not with the new version that may cost 30-50% more than to-day's rockets"

No. It was the earlier model that would have cost more, the modified SSME could have cost (if you averaged in development) on the order of $75M each. Adding a segment to the SRB and using a cheap ~$5-10M J-2 engine would run about $15-20M, and NASA was going to develop them anyway so the development is "free." The new version will save ~$50M per flight at least, it was the old four-segment/SSME one that would have cost more then its contemporaries.

"a bigger SM will weight more due to its own structure"

Again, you don't seem to understand how rocket efficiency works. You should familiarize yourself with the Cube/Square law. The service module will be heavier then for a smaller capsule, but will weigh less per kilogram of fuel then the smaller one, which gives the big capsule a payload or maneuverability advantage.

"I think that facts wins on words... the fact that an old and little Soyuz/Progress do the job of support the ISS from years clearly demontrates that a bigger capsule may be good but not absolutely necessary"

You are speaking out of rank ignorance. The ISS is barely limping along with a reduced crew that doesn't have enough hours in the day to keep up with the maintenance and repair. They are accomplishing nothing. Let me say that one more time, they are accomplishing NO useful science, and infact the station is slowly withering away without at least half a crew. If you double the number of Progress flights, and threw in the occasional ATV, you could support almost a full crew... but not any science for them to do! Some kind of cargo vessel is a must, not even trippling the number of Progress flights would be enough.

"you're right, but the "extra-fuel" we are talking about is too much since it will need to leave the lunar orbit

true... the "added fuel" don't cost nothing... unfortunately, send in orbit that extra-fuel (that in 90% of non-rescue and non-reboost missions will be NOT used) will need a bigger rocket... that costs!

You are being contradictory again and just ignoring me. I'm right, but?. Either I am right, or I am wrong, which is it? The extra fuel needed for Earth return is not "too much" for emergency use, infact its probably not even enough. That fuel will radically reduce the risk to the crew in the event the CLV fails, because it would let them avoid using the dangerous escape system. Every gram of fuel it carries is another second the crew has a better chance of survival if the booster shuts down.

And again, you are ignoring the facts here, that NASA is going to build the CLV, and it will not cost any more to make it carry 25 tonnes then ~20, this fuel does not cost any more to launch. It will not, because of the engines selected and the demands for Lunar return, it costs NASA LESS to build only the bigger Lunar CEV/CLV then to build a big one and a small one. You don't seem to have a good grasp of economies of scale.

"it's 50% true because some materials will be similar to the Apollo but great part of internal devices and materials will be 2 to 10 times lighter and smaller than Apollo (computers, electronics, panels, displays, spacesuits, etc.)"

Not really. Asside from the computers and some of the structures, the vehicle itself won't be half an order of magnetude more efficient. This will be especially true since the capsule will have two redundant heat shields.

"CLV will be completely new and its REAL advantages and reliability will be known only when (and IF...) will really fly... "

Again, this is a lie. The total risk is the sum of all the component risks, and most of the big contributors to that risk are already known quantities. All the engines, the escape system, the aerodynamics, the structures, even the avionics are all pretty well known hardware. You don't seem to know much about engineering either.

"true, but I suggest to build a 150-tons SLV with three 4-seg. SRB or a 120-tons SLV (with resized CEV, LSAM, etc.) with two 4-seg. SRB and NEVER build the 5-seg...

...not true, this is a matter of politics, then, if the Shuttle is too dangerous and the CEV too expensive for ISS' missions, politics MUST change their decisions (and NASA/ESA will do the job in adifferent way)"

Adding boosters is not the answer, because you have to add extra sets of thrust vectoring and recovery systems, which reduces efficiency. Neither your 150MT nor your 120MT with the weaker boosters would work, they would both need much more power. Even the 120MT model with the SSMEs required the five-segment boosters. Again, each booster you add yeilds a disproportionate decrease in performance, because of the non-rocket mass of the booster.

You also are blissfully ignoring the reality of the political situation. The space program is subordinate to the government, and when the government says somthing, then the space program is obliged, required, and demanded to do this thing. This thing is, to finish the ISS, fulfill our commitments to the program, and maintain domestic manned access to the station. NASA could not simply sit on the floor, pout, and refuse to budge, they are being forced to do this. Since your SLV cannot serve as a space station tender, the EELVs are not suited to manned flight, and the CLV could serve both Moon and ISS programs then the CLV will be built and the CEV sized accordingly.

gaetanomarano · 2006-05-08 07:53:19

I don't think you have a very good grasp of the concepts of reliability or spacecraft efficiency, gaetano. Two seperate capsules have twice the chance of failure, and two smaller vehicles of half the volume of a larger one will combined weigh far more then larger one. Besides, the Moon program should have four crew, and no fewer. The ISS will eventually have its six-man crew probably too, because Russia is preparing a second Zarya module to extend the life and add three more beds to the station. The US will still be obliged by treaty to provide emergency return for them, which mandates a six-seat capsule too.

not true, if a single rescue-capsule fails, six astronauts dies, with two or more capsules the chance to live double, triple, etc. since, for probability's law, not all can fail at the same moment (only for murphy's law they can...)

the 4-seats capsule don't need to be big or little, simply "standardized" to save costs... if you build a 6x capsule and use it 99% of times for 4 astronauts the costs are high... if you build a 4x (for 99% of missions) and use TWO of them when you need 6+ astronauts you save a GIANT quantity of money (not only for a lower cost capsule but also a cheper SM and launcher!)

Also the ISS for six will have sufficient docking ports for MANY rescue-Soyuz, rescue-4xCEV and (maybe) rescue-Shenzhou... NASA can accomplish its rescue mission with two 4xCEV... no need of a big 6xCEV

For instance, the capsule has to be big enough to put on a full-sized modern space suit, which are considerably bulkier then today's Shuttle pressure suit or the Apollo tetherd suits. And you have to have room to put the things. Raw volume figures, cubic meters and whatnot, are completly irrelivent. The dimensions of the capsule are what is important, that it has to be big enough on every dimension to work in.

you forget that all new moon missions will happen about 15-up years from now

do you remember the dimensions and weight of 15 years ago PCs, cellulars, etc.?

well, compare them with to-day's hi-tech stuffs and you can imagine the technology of 2020!

I think that also the spacesuits of 2020 will be incredibly new, advanced and lightweight!

"The costs counts if the extra-tons sent without any reasons are many.

true, a 20-tons-CLV may cost like a 25-tons-CLV"

Your statements are contradictory

absolutely not

the "extra-tons" is related to the 80% extra-fuel and extra-SM weight of an orbital-CEV made like a lunar-CEV

I suggest to don't build any orbital-CEV or to build a 4xCEV with an SM-light

the cost of a 20-tons and a 25-tons CLV may be similar, BOTH VERY HIGH ...then I suggest to build a 4xCEV and an SM-light with a total weight of 10-12 tons to be launched with ready available low cost rockets (after man-rate them)

No. It was the earlier model that would have cost more, the modified SSME could have cost (if you averaged in development) on the order of $75M each. Adding a segment to the SRB and using a cheap ~$5-10M J-2 engine would run about $15-20M, and NASA was going to develop them anyway so the development is "free." The new version will save ~$50M per flight at least, it was the old four-segment/SSME one that would have cost more then its contemporaries.

not true

the real costs of a CLV hardware are difficult to know now, but the early prices was around... 40M for the SRB, 60M for the SSME +2nd stage tanks +the new hardware/software to fly the SRB alone (maybe 40M) that match (only as hardware NOT with the shared CLV R&D extra-costs!) the cost of a mid-rocket (150-200M)

the new will 5-seg SRB will cost $2+ billions only of extra-R&D costs (see the recent news) that will DOUBLE or more the unit price of the 1st stage

about the J2X... it will be a new version that need time, money, R&D, tests... maybe $40-50M at to-day's prices

Again, you don't seem to understand how rocket efficiency works. You should familiarize yourself with the Cube/Square law. The service module will be heavier then for a smaller capsule, but will weigh less per kilogram of fuel then the smaller one, which gives the big capsule a payload or maneuverability advantage.

a "lunar" SM with 100% fuel and 100% tanks' dimensions can't weight like an "orbital" SM with 20% of fuel and 20% of tanks' dimensions

the orbital SM can't be 5 times light (because there are the engines, life support and other systems) but may be 60% lighter, that means less tons and a little launcher

see the problem in the invese way... the 3x Soyuz (that works well for ISS) weight 8 tons, then, an hypothetical "4xSoyuz" may weight (8/3)x4=10.6 tons, then, an orbital-CEV may weight 10-12 tons max ...simple!

You are speaking out of rank ignorance.

please avoid personal attacks, thank you

The ISS is barely limping along with a reduced crew that doesn't have enough hours in the day to keep up with the maintenance and repair. They are accomplishing nothing. Let me say that one more time, they are accomplishing NO useful science, and infact the station is slowly withering away without at least half a crew. If you double the number of Progress flights, and threw in the occasional ATV, you could support almost a full crew... [i]but not any science for them to do! Some kind of cargo vessel is a must, not even trippling the number of Progress flights would be enough. [/i]

you're right, the LEGO-like half-made ISS can't accomplish nothing but to do more it needs a full working and safe SpaceShuttle-truck to carry labs, experiments, etc.

when the Shuttle will be retired, all ISS science will be very poor (without heavy science hardware)

a 4x or 6x or 10x CEV can't change NOTHING, the 6xISS can live and work with twice Soyuz/Shenzhou launches (or 4xCEVs) and the new ATV

You are being contradictory again and just ignoring me. I'm right, [i]but?. Either I am right, or I am wrong, which is it? The extra fuel needed for Earth return is not "too much" for emergency use, infact its probably not even enough. That fuel will radically reduce the risk to the crew in the event the CLV fails, because it would let them avoid using the dangerous escape system. Every gram of fuel it carries is another second the crew has a better chance of survival if the booster shuts down. [/i]

the cost of the fuel is very low, but launch it (its weight + tank weight) is costly

where is the contradiction?

about emergency... the SM engine can't start fast like the LAS in case of emergengy, then, the CEV must use the LAS in the first 50-60 km (with 5-seg. SRB) and simply use its inertia+altitude+time+parachutes if the 2nd stage don't works

if the 2nd stage works... no problems (and no need to use the SM) because the CEV is in orbit!

And again, you are ignoring the facts here, that NASA is going to build the CLV, and it will not cost any more to make it carry 25 tonnes then ~20, this fuel does not cost any more to launch. It will not, because of the engines selected and the demands for Lunar return, it costs NASA LESS to build only the bigger Lunar CEV/CLV then to build a big one and a small one. You don't seem to have a good grasp of economies of scale.

there is some confusion, then, to simplify:

1. it's true, if NASA build the 25-tons CLV, send more fuel don't cost more, but I suggest to DON'T BUILD the useless and very expensive CLV but only an SLV for lunar missions with a 4x CEV and full SM

2. for ISS work I suggest to use only the Soyuz, Progress, ATV, ecc. or build a 4x CEV with an SM-light (10-12 tons total) and launch it with ready available mid-rockets

then, NOT two CEVs but ONE 4x CEV and two SMs (full and light) or (best) ONLY a 4x CEV with full-SM for lunar missions and no CEV for ISS

Not really. Asside from the computers and some of the structures, the vehicle itself won't be half an order of magnetude more efficient. This will be especially true since the capsule will have two redundant heat shields.

we can't know it exactly, but a 4x CEV may weight less and many new technologies will be available only in the next 15 years

Again, this is a lie. The total risk is the sum of all the component risks, and most of the big contributors to that risk are already known quantities. All the engines, the escape system, the aerodynamics, the structures, even the avionics are all pretty well known hardware. You don't seem to know much about engineering either.

absurd, it's like evaluate the reliability of a new car from the reliability of its parts

many of the NEW parts of the CLV will be the most CRITIC

we must wait, the CLV (real) reliability must be known only when REAL rockets will fly

Adding boosters is not the answer, because you have to add extra sets of thrust vectoring and recovery systems, which reduces efficiency. Neither your 150MT nor your 120MT with the weaker boosters would work, they would both need much more power. Even the 120MT model with the SSMEs required the five-segment boosters. Again, each booster you add yeilds a disproportionate decrease in performance, because of the non-rocket mass of the booster.

my "first choice" (see my article) is for "resized" moon missions that need only a 100-110 tons SLV with 4-seg. SRB

You also are blissfully ignoring the reality of the political situation. The space program is subordinate to the government, and when the government says somthing, then the space program is obliged, required, and demanded to do this thing. This thing is, to finish the ISS, fulfill our commitments to the program, and maintain domestic manned access to the station. NASA could not simply sit on the floor, pout, and refuse to budge, they are being forced to do this. Since your SLV cannot serve as a space station tender, the EELVs are not suited to manned flight, and the CLV could serve both Moon and ISS programs then the CLV will be built and the CEV sized accordingly.

I know how politics think, but, if the Shuttle is too dangerous to fly, politics can't make it safe with a new law... if they can, then... they can make also a law to win the cancer, abolish earthquakes, etc...

The SLV is for moon missions, for orbital access to space NASA can build a standard (moon) 4x CEV with an SM-light and launch this 10-12 tons vehicle with one of the many already available american mid-rockets ...no need of CLV.

.

SpaceNut · 2006-05-08 08:03:56

A new EELV v SDV - A new spacedaily opinion piece

Rocket Business model for shuttle delta IV atlasV - and others good or bad

gaetanomarano · 2006-05-08 08:10:25

A new EELV v SDV - A new spacedaily opinion piece

sorry, but I've made hundreds posts about this (and other) proposal on another space forum (from october 2005), WEEKS before Jeff Bell's article... (maybe he reads space forums...?) and, of course, I agree with "his" (or my???) opinions...

.

SpaceNut · 2006-05-08 08:22:01

A new EELV v SDV - A new spacedaily opinion piece

sorry, but I've made hundreds posts about this (and other) proposal on another space forum (from october 2005), WEEKS before Jeff Bell's article... (maybe he reads space forums...?) and, of course, I agree with his (or my???) opinions...
.

I should have put in that these are the forum discussion here on Newmars for the links.

A lot of ground has been discussed on why EELV's would need to be redone to make them man compatible.

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