Which Orion is better? A (smallSM) "CorkScrew-Orion" or a (bigSM) "SwissKnife-Orion"?

[gaetanomarano]

LOL! You sure haven't been paying much attention, have you?

everyone can read (all) your previous posts in this thread to know if I've "paid attention" or not

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[Launch window]

Gaetanomarano, the CEV you have advocated building will be on the order of 40 mT. This means the only vehicle capable of launching it to the Moon is an Ares V. Every time you launch a CEV to the Moon it will cost an Ares V. This is an underutilization the Ares V’s payload capability, therefore making a solo CEV launch more expensive than it needs to be. To make the cost of a solo CEV launch more economical would require a downsizing of the Ares V; however this means it can no longer launch a CEV+LSAM, which is its reason for being in the first place. We need the large payload capacity of the Ares V for normal CEV+LSAM missions.

The only other alternative to launch the CEV to the Moon is another launcher smaller than the Ares V but still about 2/3rds the size (let’s call it the Ares IV). Clearly building another big launcher so close to the capacity of the Ares V is tremendous waste – we simply do not need two heavy launch vehicles in that class.

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building two heavy laucher would be very expensive and NASA's budget is already tight enough

[Bob B.]

in your previous posts, you've calculated the TEI (not Polar!) hypergolic propellants' mass for the (11.5 mT dry mass) Orion/SM at 9.5 mT

No, I did not. What I calculated was the amount of propellant required for Orion to produce the 1,855 m/s delta-v as specified in the document that accompanied the announcement of Lockheed-Martin as the prime contractor. You are (again) making the wrong assumption that all of Orion's propellant is for TEI; it is not. Propellant is budgeted for other maneuvers in addition to TEI.

I don't know how much delta-v NASA has budgeted for TEI (it might be in the ESAS report but I've yet to see it). If we assume 1,000 m/s, which is about the average for Apollo, and an after TEI mass of 12 mT (its tanks won't be completely empty), then

Propellant = Mf*e^(dV/(Isp*g)) - Mf

TEI Propellant = 12*e^(1,000/(320.5*9.80665)) - 12 = 4.50 mT

[Bob B.]

Okay, who voted for the BigSM? Gaetanomarano?

[Doodler]

Launchwindow. So sayeth the pollin' thing.

And somehow, Wolf-S voted small twice.

[Bob B.]

since the full Apollo SM propellants' mass was 18,4 mT (less the LOI/TEI mass) the residual propellants' mass was 2.9 mT but only (about) 0.8 mT was used "for other" since the propellants' mass after TEI was 2.1 mT

maybe, part of this (2.1 mT) residual propellants was used to correct the CSM trajectory in the moon-earth flight, but great part of it was (probably) only an extra-mass loaded to give some redundancy.

The linked data appears to be for the Apollo 11 mission. It is true some of the SPS propellant was a reserve; however Apollo 11 was atypical in some ways. The amount of maneuvering the CSM had to perform while in lunar orbit increased on later missions.

For example, one of the maneuvers was a plane change prior to LM ascent. This was necessary because, as the Moon rotated, the LM’s landing site would slowly move out of the plane of the CSM’s orbit. The CSM had to adjust its orbital plane so that its flight path once again passed over the landing site. The LM could then insert itself into the same orbital plane, which was required for rendezvous. The longer the LM was on the surface the more it moved out the CSM’s path, thus the greater the plane change. Plane changes require a lot of propellant; therefore the longer missions required more propellant.

[Bob B.]

So sayeth the pollin' thing.

Huh... I just learned something new; I didn't know you could see the results. I never tried clicking on the numbers before.

[Doodler]

Huh... I just learned something new; I didn't know you could see the results. I never tried clicking on the numbers before.

Could be an option set when you set up the poll.

[gaetanomarano]

building two heavy laucher would be very expensive and NASA's budget is already tight enough

the bigOrion don't need another AresV but only a enhanced Ares-I
a 65 mT Ares-II may have the same R&D costs of the Ares-I but with all the (giant!) advantages of an autonomous Orion

[gaetanomarano]

No, I did not. What I calculated was the amount of propellant required for Orion to produce the 1,855 m/s delta-v as specified in the document that accompanied the announcement of Lockheed-Martin as the prime contractor. You are (again) making the wrong assumption that all of Orion's propellant is for TEI; it is not. Propellant is budgeted for other maneuvers in addition to TEI.
TEI Propellant = 12*e^(1,000/(320.5*9.80665)) - 12 = 4.50 mT

you have calculated the TEI propellants' mass at 9.5-10 mT here and the total Orion+SM mass at 21-21.5 mT here

you can't justify the giant 5 mT amount of extra propellants' mass (more than the TEI fuel!) with any exotic "maneuverings" since, at the end of a moon mission, the Orion must ONLY come back to earth!

it's interesting that (now) with a credible value for the lunar-SM propellants' mass (4.5 mT + 2 mT for redundancy) we can (also) evaluate the (possible) mass of an orbital-Orion for ISS with less propellant (but sufficient to reach the ISS, reboost, maneuverings, reentry, etc.)

I think that 2.0 mT + 0.5 mT for redundancy and maneuvering = 2.5 mT total is a reasonable value, so, the full orbital-Orion weight may be around 11.5 mT (Orion+SM dry mass) + 2.5 mT (propellants) + 6.2 mT (LAS) + 0.6 (2nd stage adapter) = 20.8 mT

and "20.8 mT" is close to the max payload (21 mT) of the latest (ATV) version of the Ariane5... then, an orbital-Orion can be launched (also) with an Ariane5 like I suggest in my June 30 article... (sorry, I'm right again...)

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[gaetanomarano]

Okay, who voted for the BigSM? Gaetanomarano?

I'll be happy if other users will vote PRO my bigOrion proposal, however, I've published my bigOrion's articles before the this thread/poll and my first target MUST be to demontrate that my proposals can (really) work ...that's the thing I've done (with a single shot) for (both) the bigOrion and the ArianeCEV...

[gaetanomarano]

The amount of maneuvering the CSM had to perform while in lunar orbit increased on later missions.

like the Apollo, I've added 2 mT of "redundancy and maneuverings" extra-fuel in my latest evaluations of the Orion's mass

[Bob B.]

you have calculated the TEI propellants' mass at 9.5-10 mT here

No, I did not. Please read carefully what I wrote …

This is enough information to make a fairly good estimate of the SM propellant load, which Mark Wade and I have already done. Those calculations show that 9.5 to 10 mT is a reasonable estimate. Your figure of 7 mT is simply not creditable.

I wrote “SM propellant load”, there is no mention of “TEI propellants' mass”. This calculation has been repeated several times and I have always maintained it is the total SM propellant mass based on the delta-v requirement of 1,855 m/s. I have never claimed it to be TEI only. In fact, four days ago I specifically explained this to you in another of your threads…

if the propellant for TEI-only is (e.g.) 9 mT, the extra propellant for an (autonomous) LOI must be MORE than 9 mT (since, at LOI, the engine must brake the Orion + the TEI-fuel mass)

Herein lies the crux of the problem. The 9-10 mT of CEV propellant is for more than just TEI. The CEV is probably going to have to perform several maneuvers, similar to what Apollo did. Apollo had to perform altitude changes, plane changes, course corrections, etc. TEI itself required only about 1,000 m/s delta-v. The CEV has a delta-v of 1,855 m/s. …

I clearly explained that TEI is only a portion of the delta-v/propellant budget, and I even told you that TEI on an Apollo-like mission is about 1,000 m/s. This 1,000 m/s number is exactly the same delta-v I used to calculate the TEI propellant mass of 4.5 mT (post #63). I didn’t perform the calculation four days ago because it wasn’t pertinent to the discussion at that time, but I clearly set forth the parameter upon which it is based. I calculated it today only because this is the first time it came up in the conversation.

and the total Orion+SM mass at 21-21.5 mT here

Yes, and I still stand by that calculation.

[gaetanomarano]

wrote “SM propellant load”, there is no mention of “TEI propellants' mass”...

only a "linguistic trick"... for over a week (on this thread and on the "giant mistake Orion" thread) we have discussed ONLY (as everyone can read) of the propellants' mass the Orion SM needs for TEI or LOI+TEI and (absolutely) NOT of any extra-propellants "loaded" (maybe) to help Orion play Baseball around the Moon...

...I calculated it today only because this is the first time it came up in the conversation.

and (exactly) 30 minutes after the NEOWatcher post...

I still stand by that calculation.

the ONLY reason to add 5 mT of (useless and unused) propellants' mass in the SM tanks is to support the 5-segments SRB for the Ares-I (so it can lift 5 mT of dead-weight)

[Bob B.]

only a "linguistic trick"... for over a week (on this thread and on the "giant mistake Orion" thread) we have discussed ONLY of the propellants' mass the Orion SM needs for TEI or LOI+TEI and (absolutely) NOT of any extra-propellants "loaded" (maybe) to help Orion play Baseball around the Moon... (as everyone can read!)

Please speak for yourself only. It is you who has been making that same mistake over and over for a week and I’ve been trying to correct you, but you are apparently incapable of learning anything. It is complete ignorance to talk only of LOI+TEI because any lunar landing mission requires more than that. I didn’t speak in such limited terms because I’m not stupid enough leave out the propellant necessary to complete the entire mission.

and (exactly) 30 minutes after the NEOWatcher post...

No, I clicked the “Submit Reply” button exactly 30 minutes after NEOWatcher’s post. When I began to write my reply and calculations, NEOWatcher hadn’t posted yet. I didn’t see his post until after I submitted mine.

I really resent your insinuation; and if this forum didn’t have rules against it I’d let you know in no uncertain terms what I think of it.

the ONLY reason to add 5 mT of (useless and unused) propellants' mass in the SM tanks is to support the 5-segments SRB for the Ares-I (so it can lift 5 mT of dead-weight)

Regrettably you’ll probably never evolve enough to realize just how asinine this comment is.

[gaetanomarano]

...any lunar landing mission requires more than that...

5 mT ...more than TEI fuel...

...NEOWatcher hadn’t posted yet...

sorry, I've only noted the coincidence

...if this forum didn’t have rules against it...

...not even for some "words" you write in this and other posts

...this comment is.

after so many posts about the SRB, you can't deny to be a supporter of the 5-segments SRB ....maybe, you are (only) "happy" to see it used in the new rockets...

[stutefish]

I have thought for some time now that these threads should all be in "against the mainstream".

As far as I can tell, the only thing keeping them out of "conspiracy theories" is that Gaetano has never actually addressed the fact that if NASA really were as incompetent and ignorant as he implies, there would pretty much have to be a conspiracy of epic proportions to keep it quiet.

[gaetanomarano]

..."conspiracy theories"...

there is NOTHING about any "conspiracy theories" in my articles/threads/posts... ONLY good (and, maybe, a little "alternative") ideas about spacecrafts

[Doodler]

I dunno about against the mainstream, you'd actually have to be swimming to pull that off, he's been flopping like foundered flounder through every thread on the Orion he's started.

[stutefish]

there is NOTHING about any "conspiracy theories" in my articles/threads/posts... ONLY good (and, maybe, a little "alternative") ideas about spacecrafts

Exactly my point. There's nothing about conspiracy theories in your article, which is why they don't belong into the "conspiracy theories" section of the board.

On the other hand, it seems to me that your positions strongly imply that NASA is staffed by people who are incompetent and ignorant on a grand scale--so grand, in fact, that a conspiracy would be necessary to cover it up. But you never address this implication. Which is what keeps these threads out of the "conspiracy theories" section. Q.E.D.

[Bob B.]

...if this forum didn’t have rules against it...

...not even for some "words" you write in this and other posts

I get a bit upset we people question my integrity. Why, after I show you the exact mathematical solution and a four-day-old post in which I specifically stated the premise for solution, do you find the need to insinuate that I only knew the answer because I looked it up in a NASA document?

[gaetanomarano]

...it seems to me that your positions strongly imply that NASA is staffed by people who are incompetent and ignorant on a grand scale...

absolutely not true... the ESAS plan (with some changes) can work "as is" with the 5-segments SRB, the small Orion, etc.
my articles are only suggestions to make a BETTER plan and to accomplish more and better missions

[gaetanomarano]

...get a bit upset...

probably you already was "upset" in the past, since you have used similar (explicit or allusive) "words" against me many other times in other threads
however, I suggest to close the "diplomatic incident" here

[Bob B.]

probably you already was "upset" in the past

Not "upset" necessarily, I would say "frustrated" is a better word. Believe it or not, I’m really trying to help you understand the science behind these issues. I’m not arguing just to be difficult.

Let me also point out that I’m an engineer and have spent years studying the science we’ve been discussing. As someone with professional credentials, I feel insulted when you imply I don’t know my business. Although you have been generally polite, it is not fair to play the innocent victim routine while claiming you haven't insulted anyone. What may not seem like an insult to you may be an insult to others.

I suggest to close the "diplomatic incident" here

Agreed, at least until the next "incident".

[JMV]

I've fiddled with the numbers and unless I'm totally wrong the 855 m/s "extra" delta-v can provide the Orion a plane change of 30 degrees at 100 km orbit. Doesn't seem all that much considering the angle from equatorial to polar orbit is 90 degrees.

I suspect most of that "extra" delta-v is budgeted for these plane change manouvers since the Project Constellation aims for high inclination landings. I'd say that the 5 mT of propellant, that gaetanomarano seems to think is dead-weight, will be very much needed.

Can anyone make educated guesses on what kind of plane change manouvers are required of the Orion vehicle?

And Gaetano, may I suggest you familiarize yourself with the Tsiolkovsky rocket equation to save much embarrassment.

[Bob B.]

Here is what the ESAS Report says about the CEV SM propellant:

5.2.3.2 Lunar CEV SM

5.2.3.2.3 Subsystem Description

Propellant

Propellant for the CEV SM consists of the following components:

• Used service propulsion system fuel propellant,
• Used service propulsion system oxidizer propellant,
• Used RCS fuel propellant, and
• Used RCS oxidizer propellant.

CEV total SM service propulsion system/RCS propellant is calculated for four major delta-V maneuvers in the mission. For each maneuver, the assumed service propulsion system Isp is 363.6 sec and the RCS Isp is 317.0 sec.

• The first major maneuver is rendezvous and docking with the LSAM in LEO. The CEV is inserted by the LV upper stage into a 55- x 185-km (30- x 100-nmi) elliptical orbit, while the LSAM and EDS are loitering in a 296-km (160-nmi) circular orbit. The CEV will then rendezvous with the LSAM and dock. The required delta-V for rendezvous and docking is estimated at 119.4 m/s for the service propulsion system and 25.1 m/s for the RCS, while the initial CEV mass prior to the maneuver is 23,149 kg.
• The second major maneuvers are station-keeping in LLO while the crew is on the surface and a contingency 5-deg plane change in the event of a worst-case anytime ascent from a 85-deg latitude landing site. The required delta-V for station-keeping is estimated at 15 m/s for RCS and 156 m/s of service propulsion system delta-V is included for the plane change. The initial CEV mass prior to these maneuvers is 21,587 kg.
• The third major CEV maneuver is TEI from LLO. For a worst-case anytime return from a polar orbit, a 90-deg plane change may first be needed to align the spacecraft’s velocity vector with the V-infinity departure vector. The method chosen to accomplish this maneuver is to use a sequence of three impulsive burns, where the first burn raises the CEV orbit apolune from a 100-km orbit to an orbit with a period of 24 hours. The CEV coasts to the correct position to perform the 90-deg plane change and then coasts to perilune to complete TEI. The required delta-V for TEI is estimated at 1,449 m/s for service propulsion system. This maneuver also includes +/–90-deg control of the arrival coazimuth at Earth and +/–12-hr control of the nominal 96-hr return time from the third TEI burn. The initial CEV mass prior to the maneuver is 21,057 kg.
• The fourth maneuver is a 10-m/s mid-course correction using an RCS. This is used to correct any errors resulting from an imprecise TEI burn. The initial CEV pass prior to the maneuver is 14,023 kg.
• The fifth and final SM maneuver is to safely dispose of the SM after CM separation. The required RCS delta-V for disposal is 15 m/s, and the initial SM mass prior to the burn is 4,372 kg.

Of course we know several changes have been made since this was written. The switch to N2O4/MMH propellant will result in a lower specific impulse. We've seen one article that said the AJ10-118K would be used, which has an Isp of 320.5 sec. And for comparison, the Apollo RCS had an Isp of 290 sec. The delta-V of the listed maneuvers total 1,724.4 m/s for the service propulsion system and 65.1 m/s for the RCS, for a combined total of 1,789.5 m/s. The most recent information released by NASA gives a revised delta-V of 1,855 m/s, however I don't know if the is the service propulsion system only or the SPS + RCS total. We also know there has been an overall mass reduction, so the mass listed in the report is outdated. There may be other changes as well that we don't know about.

[gaetanomarano]

...you understand the science...

my purpose here is not to start a "space engineering course in ten easy lessons" but only to discuss about some "concepts" of new vehicles, rockets and missions architectures
I don't need to "design, build and launch" the objects I propose since I'm not an enginner and (also) I don't need to do the job that NASA and space companies must do
for me, it's sufficient to know (with sufficient accuracy) if my idea can work or not
having more time I can learn everything, but I don't need (nor have time) to do that
I have not a space company and I don't build rockets, then, I don't need to calculate all details of a vehicle
but, (e.g.) also if I will start a space company, I don't need to calculate or design anything
in every (space or not space) company there are many functions: managers (that do decisions without calculate nothing) "architects" of products (that may know all about calculations and design or only something or nothing) and the engineers that MUST know ALL about calculations, design, tests, etc.
to remain in the example, I'm like an "architect" and I can't be (not I need to be nor I can become in "ten easy lessons") an engineer
a practical example is the bigOrion
I don't need to design it, nor calculate all details of the hardware and of its mission
I only need to know that (with only 4.5 mT of propellants for TEI, 16 mT for LOI, etc.) my idea is feasible, nothing more, nothing less
if NASA or LM or ESA will decide to build (e.g.) the bigOrion, can (simply) use their army of engineers to do that job

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[gaetanomarano]

...the 5 mT of propellant, that gaetanomarano seems to think is dead-weight, will be very much needed...

since months ago NASA has reduced many of the ESAS ambitions (including the change of orbits to land on different places like Poles) that extra propellans' mass IS dead-weight
also, I've read (so far) that all maneuverings (including the change of orbit) must be done with LSAM engines
(so far) I've read that CEV engine has only two functions: TEI burning ath the end of mission and an EMERGENCY (and remote-controlled) change of orbit to dock with the LSAM if the latter has problems to reach the CEV
for these jobs, 4.5 mT or propellants (for TEI) and 2 mT of propellant (for extra maneuvering and redundany) are more than sufficient
the giant quantities of the ESAS plan's CEV was due (only) to the bigger CEV/SM in its first version (but now it's unnecessary)
of course, we can discuss of the orbital change option, but knowing that it is not part of the "plan"

...Tsiolkovsky rocket equation...

about this point, you can read my reply to Bob B. post

[gaetanomarano]

...we know several changes have been made since this was written...

several and RADICAL changes (of weights, propellants, etc.)

...know there has been an overall mass reduction, so the mass listed in the report is outdated...

VERY MUCH "outdated" ...ultimately, the old ESAS data CAN'T be used as a reliable base of discussion/evaluation

[Bob B.]

my purpose here is not to start a "space engineering course in ten easy lessons" but only to discuss about some "concepts" of new vehicles, rockets and missions architectures
I don't need to "design, build and launch" the objects I propose since I'm not an enginner and (also) I don't need to do the job that NASA and space companies must do
for me, it's sufficient to know (with sufficient accuracy) if my idea can work or not
having more time I can learn everything, but I don't need (nor have time) to do that.

If you refuse to learn the science, then you cannot know whether your concepts will or will not work. Evaluating the validity of the concepts requires real science and engineering knowledge, which you admittedly don’t have and you refuse to learn. Without real expertise you are only guessing.

I have not a space company and I don't build rockets, then, I don't need to calculate all details of a vehicle
but, (e.g.) also if I will start a space company, I don't need to calculate or design anything
in every (space or not space) company there are many functions: managers (that do decisions without calculate nothing) "architects" of products (that may know all about calculations and design or only something or nothing) and the engineers that MUST know ALL about calculations, design, tests, etc.
to remain in the example, I'm like an "architect" and I can't be (not I need to be nor I can become in "ten easy lessons") an engineer.

In your example, is it not advisable for the architect to listen to the expert advice and opinions of the engineers he has hired to perform the design calculations? Suppose that every time an engineer went to the architect with the result of a design calculation, the architect said, “I don’t believe you; your calculation can't be right because it differs from my opinion.” Wouldn’t that be absurd? Shouldn’t the architect defer to the authority of the experts; particularly when the architect admittedly lacks that expertise?

Sadly the scenario I describe above is exactly want you are doing. You are refusing the calculations and opinions of people with real expertise in the area of rocket science simply because what they are telling you conflicts with your opinion. If you are not going to take the time to learn the science for yourself, then you have not earned the right to tell the experts they are wrong.

a practical example is the bigOrion
I don't need to design it, nor calculate all details of the hardware and of its mission
I only need to know that (with only 4.5 mT of propellants for TEI, 16 mT for LOI, etc.) my idea is feasible, nothing more, nothing less.

You can’t know whether or not your concept is feasible without performing calculations to verify it, and you admittedly don’t know how to perform the calculations. When others do it for you, the calculations show your estimations are incorrect.

Gaetanomarano, when your opinion is at odds with reality it is time to change your opinion. The physical world is under no obligation to conform to your expectations.