View Poll Results: Which Orion is better? A (smallSM) "CorkScrew Orion" or a (bigSM) "SwissKnife Orion&q

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

  1. #361
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    Bob, are these raw scores or weighted scores? (I suspect that the weighted value--eheh--of the TPS-panel-to-orbit score would overwhelm any points the underside design might rack up, but then, I'm a layman...)

    Also, it seems to me that the canard solution, while proven, requires an additional subsytem that is not required if the ACS performs the task. I'm tempted to call that one in favor of the underside solution on account of the simplicity gains. Am I right to do so?

  2. #362
    Quote Originally Posted by stutefish View Post
    Bob, are these raw scores or weighted scores?
    Raw. Had the score been closer I might have tried a weighted scoring system to help determine the winner.

    Quote Originally Posted by stutefish View Post
    (I suspect that the weighted value--eheh--of the TPS-panel-to-orbit score would overwhelm any points the underside design might rack up, but then, I'm a layman...)?
    I tend to agree. That one item alone may be enough to knock the underside system out of contention.

    Quote Originally Posted by stutefish View Post
    Also, it seems to me that the canard solution, while proven, requires an additional subsytem that is not required if the ACS performs the task. I'm tempted to call that one in favor of the underside solution on account of the simplicity gains. Am I right to do so?
    I almost called this one even. What I like about the canard is that once deployed it is a passive means to achieve and maintain attitude by simply using aerodynamics. The canard just pops out and that's it. On the other hand, using the ACS is an active means of achieving and maintaining attitude. The system must sense the capsule's attitude, fire the thrusters to turn the capsule, fire them again to stop the rotation, and continue firing them as necessary to maintain correct attitude. Although the canard is an extra subsystem, it seems less risky to me. Of course attitude control systems are pretty reliable too so I wouldn't be opposed grading it even, but I wouldn't go so far as calling it in favor of the underside system. But that's just my opinion.
    Last edited by Bob B.; 2007-Feb-15 at 04:42 PM. Reason: spelling

  3. #363
    Quote Originally Posted by gaetanomarano View Post
    by comparison with other solid rockets like the Delta GEM-60 that has:

    33.8 mT GLOW
    29.5 mT propellent
    3.85 mT dry mass (about 10% the weight of the full rocket)
    The 10% figure is about right. Solid rocket motors typically have a propellant mass fraction of about 0.9.

    Quote Originally Posted by gaetanomarano View Post
    then, the four motors of "my" LAS for a standard Orion may weigh 2,480 kg. + 248 kg. = 2,728 kg. in total
    No, your math is off a bit. It is 10% of the total mass, not 10% of the propellant mass. The correct math is, 2,480/0.9 = 2,756 kg.

    Quote Originally Posted by gaetanomarano View Post
    while, the four motors of "my" LAS for a (15% lighter) 8 mT TBS-Orion may weigh less than 2.3 mT (only!!!)
    Dont forget that if Orion is lightened then the tower LAS gets to be reduced in size as well. Comparing the mass of your system on an 8 mT capsule to a competing system on a 9.5 mT capsule isnt being fair. You need to maintain an apples-to-apples comparison for a fair analysis.

    Quote Originally Posted by gaetanomarano View Post
    of course, we must include the LAS/Orion Nose Cone and LAS Attitude Jets dry mass
    And the attitude control propellant (which must include enough to take over the function of the canard), and the boost protective cover, and the jettison motors/mechanisms, and TPS protection panel, and the SM structural modifications.

    Your system must maintain the same functionality of the competing tower system. What you are proposing is really nothing more than a reconfiguring of the same major components. The underside LAS offers no weight advantage whatsoever and your mass estimates are laughable.

  4. #364
    I’ve had some further thoughts on my scoring of the tower vs. underside LAS…

    CANARD SECTION
    It may not be fair to say the attitude control system (ACS) of the underside configuration requires more propellant due to the absence of a canard. There is a latter abort mode in which the canard is ineffective due to the high altitude. In this mode the ACS must turn the capsule anyway, thus it may already have enough propellant without adding more. This probably gives a small weight advantage to the underside system because of the elimination of the canard subsystem. However I still see the canard as a simpler and more reliable method. Furthermore, since the tower LAS also has an ACS, there is a backup subsystem. I’m going to change my score to even with the weight advantage going to the underside system and the risk/safety factor going to the tower system.
    Advantage: Even

    JETTISON MOTOR
    I forgot to mention that Gaetano’s nose cone/attitude control system will definitely require a jettison motor to push this assembly away from the vehicle during ascent. Without a jettison motor the nose assembly will have to ride all the way to orbit, which imparts such a large weight penalty that we can pretty much kiss the underside system goodbye. (EDIT) Furthermore, the boost projective cover should be jettisoned once the aerodynamic loads have adequately subsided, which can probably be done in combination with the nose cone/ACS using the same jettison motor.
    Advantage: Even


    Revised Score
    Tower: 4
    Underside: 1
    Even: 5

    Winner: Tower
    Last edited by Bob B.; 2007-Feb-15 at 04:51 PM. Reason: as noted

  5. #365
    CANARD SECTION
    It may not be fair to say the attitude control system (ACS) of the underside configuration requires more propellant due to the absence of a canard. There is latter abort mode in which the canard is ineffective due to the high altitude. In this mode the ACS must turn the capsule anyway, thus it may already have enough propellant without adding more. This probably gives a small weight advantage to the underside system because of the elimination of the canard subsystem. However I still see the canard as a simpler and more reliable method. Furthermore, since the tower LAS also has an ACS there is a backup subsystem. I’m going to change my score to even with the weight advantage going to the underside system and the risk/safety factor going to the tower system.
    Advantage: Even
    It's quite complex. In lower atmosphere, where the canards are effective, aerodynamic loads may require more performant engines (in case of no canards) than in high atmosphere/space, and the net result may be lighter engines in a design with canards.

    btw Bob's scoring system is one of the techniques actually used in real tradeoffs to get a vision on the relaitve quality of alternatives.

  6. #366
    Quote Originally Posted by Nicolas View Post
    It's quite complex. In lower atmosphere, where the canards are effective, aerodynamic loads may require more performant engines (in case of no canards) than in high atmosphere/space, and the net result may be lighter engines in a design with canards.
    Yes, I thought about how the aerodynamic loads might affect attitude control effectiveness; as you say though, it's complex. My gut stills tells me to go with the canard subsystem, but without more definitive mass numbers I decided to just call it even.

  7. #367
    Quote Originally Posted by Nicolas View Post
    ...re-entry works on the bottom of the capsule. Ascent on the top. I've explained that before...
    thanks for your "explain"! ...never supposed that before!
    ...assume the max skin temperature is for example 400C...
    the Apollo reentry time was over 15 MINUTES at 2,760C of max external temperature (while the max external temperature of the Orion at reentry will be 2,650C) ...a VERY HOT plasma that covers the entire surface of the capsule (with its peak value on the TPS)

    from the Ares-I flight profile (post #342) you can see that after 58.9 sec. an Orion will reach 12 km. of altitude and Mach 1.6 ...and I guess that it may need about 30 sec. to reach 25 km. of altitude and Mach 2.5 (like every common F-15 Eagle can do) ...then, after lift-off, an Orion may experience the external temperature you GUESS (400C) just for a few seconds (maybe, 20-30 sec. max) while it flies at (both) high speed AND a dense atmosphere

    well... I doubt very much that a capsule built to fly 15 MINUTES at 2,650C (without any BPC or Nose Cone) may even be damaged (just a little bit) flying (only) 20 SECONDS at (only) 400C... it's simply RIDICULOUS to claim that!

    ...and don't forget that, while and after the 15 minutes Orion "cooking" at 2,650C, its Attitude Control Jets MUST WORK WELL and its parachutes' outlets MUST REMAIN INTACT !!!

    ...BPC means ONLY "BOOST Protective Cover" ...nothing more, nothing less!

    ...and, if you still have some doubts... you can see with your eyes on NASA TV that, also at high altitude and speed, rockets and shuttles NEVER look/become like this >>>


    image (c) Wikipedia

    .
    Last edited by gaetanomarano; 2007-Feb-16 at 01:09 AM. Reason: grammar

  8. #368
    Quote Originally Posted by Bob B. View Post
    ...your proposal is far riskier from a detachment standpoint because you have at least two components that must be jettisoned while the tower is only one piece...
    if you add a "safety upgrade" to an already safe device (generally) it becomes SAFER ...however, I don't insist on this point since my goal is NOT to carry in orbit the same (standard-Orion) payload with the same (5-seg.SRB) Ares-I but carry in orbit a lighter Orion with a smaller Ares-I (or another rocket)
    .

  9. #369
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    Quote Originally Posted by gaetanomarano View Post
    thanks for your "explain"! ...never supposed that before!

    the Apollo reentry time was over 15 MINUTES at 2,760C of max external temperature (while the max external temperature of the Orion at reentry will be 2,650C) ...a VERY HOT plasma that covers the entire surface of the capsule (with its peak value on the TPS)

    from the Ares-I flight profile (post #342) you can see that after 58.9 sec. an Orion will reach 12 km. of altitude and Mach 1.6 ...and I guess that it may need about 30 sec. to reach 25 km. of altitude and Mach 2.5 (like every common F-15 Eagle can do) ...then, after lift-off, an Orion may experience the external temperature you GUESS (400C) just for a few seconds (maybe, 20-30 sec. max) while it flies at (both) high speed AND a dense atmosphere

    well... I doubt very much that a capsule built to fly 15 MINUTES at 2,650C (without any BPC or Nose Cone) may even be damaged (just a little bit) flying (only) 20 SECONDS at (only) 400C... it's simply RIDICULOUS to claim that!

    ...and don't forget that, while and after the 15 minutes Orion "cooking" at 2,650C, its Attitude Control Jets MUST WORK WELL and its parachutes' outlets MUST REMAIN INTACT !!!

    ...BPC means ONLY "BOOST Protective Cover" ...nothing more, nothing less!

    ...and, if you still have some doubts... you can see with your eyes on NASA TV that, also at high altitude and speed, rockets and shuttles NEVER look/become like this >>>


    image (c) Wikipedia

    .
    Again, you are being intentionally obtuse. When it is ascending, the heat shielding it has is irrelevant. It is ascending with the side that does not have a heat shield facing the 400C wind. When it is reentering, the HEAT SHIELDED side is facing into the wind. This makes a big difference in how much it can take.

  10. #370
    Quote Originally Posted by gaetanomarano View Post
    ...BPC means ONLY "BOOST Protective Cover" ...nothing more, nothing less!
    And what exactly do you think "boost" is referring to?

  11. #371
    thanks for your "explain"! ...never supposed that before! [long, colourful explanation below it]
    Apparently we'll have to explain it once again as you keep on using the wrong argument. Also an argument totally contrary to your arguments when talking about the double truncated whateveryoucallit shape of your Orion versus the cone on re-entry, but anyway.

    And yes, the 400°C is just a guess. An educated guess though. We have a 2500°C stagantion temperature as a fact. We have a 650°C skin temperature for X-15 at those flight conditions as a fact. We have the argument of less exposure time for Orion (lowering the temperature, as X-15 hadn't reached equilibrium yet) and less aerodynamical shape for Orion (increasing the temperature due to more slowdown of the air). For the latter, note for a (relatively ) low leading edge skin temperature you've got 2 good things: an aerodynamical shape, causing little slowdown (example the X-15 wing leading edge) or a blunt shape causing boundary layer to form (example lower heat shields) and thereby decreasing skin friction and the force of heat channeling. The upper side of a capsule is blunt nor highly aerodynamical, it's a brute in between thing with, in practice, lot of irregularities. I've been conservative by taking the overall effect of these two as 2/3 of the X-15. If the wind gets trapped somewhere in a small pit and comes to a standstill, that would mean a local airflow of 2500°C hitting the surface (and pushing on it with a lot of force, both causing drag and trying to push the hot air inside). Yes, Pitot tubes must be able to withstand a lot already on regular jets .

    So there certainly is need for good protection. And as that protection is only required during ascent, it's efficient to throw it away afterwards, which is why they use a cover. That same cover protects against a variety of other things, a very goood design indeed.

  12. #372
    This webpage from Boeing says:

    The boost protective cover protected the command module from temperatures that reached 1200 degrees during the launch phase.
    They don't say but I assume that is probably Fahrenheit degrees, which converts to 650-degrees C. Also note that Boeing confirms what Nicolas and I have been saying, the BPC protected the CM during launch phase. This requirement does not change with the elimination of a LAS tower.

    Let me further add that Gaetanos design will still require a jettison motor on the nose cone/attitude control assembly; and the exhaust from this motor will be even closer to the CM than then that from the tower jettison motor. Thus, even if Gaetanos argument that the BPC is needed only for protection from motor exhaust is correct, the BPC is still needed because his design does not eliminated that requirement.

  13. #373
    I've even seen °R (Rankine) temperature scales used, but that was just once (X-15 data IIRC). The interval for Rankine is identical to Fahrenheit though.

  14. #374
    Quote Originally Posted by Bob B. View Post
    ...outrageous mass saving claims...
    you may be right in that ONLY if a REAL Orion with the newLAS (after hundreds wind-tunnel tests and many REAL flight tests) will still need a Boost Protective Cover and other heavy parts of the tower-LAS ...while, if the Orion with the newLAS doesn't need them, the MINIMUM mass' saving will be over 2.5 mT vs. the standard-Orion's tower-LAS and over 3 mT vs. a TBS-Orion's tower-LAS

    some of the points of your post will be better explained in the first newLAS article's update ...however, in brief:

    NOSE CONE: my design MERGES the tower-LAS' Nose Cone, Adapter Cone and Attitude Control Motors in a single (smaller and lighter) module ...advantage: newLAS

    ATTITUDE CONTROLS: smaller, lighter and merged with the Orion's nose cone ...advantage: newLAS

    CANARD SECTION: it can be used only in a brief part of ascent and it's not indispensable, then deleted in my design to save on volume and mass ...advantage: newLAS

    INTERSTAGES: the three tower-LAS' intestages are unnecessary (and the SM doesn't need to be "resized" but just "reshaped") ...advantage: newLAS

    ADAPTER CONE: in my design it's merged with the Orion nose cone (that is smaller and more aerodynamic than the tower-LAS Adapter Cone) ...advantage: newLAS

    BOOST PROTECTIVE COVER: my design doesn't need any giant and heavy BPC ...advantage: newLAS

    JETTISON MOTOR: as real tests will show, the SM external shape, the SM/abort-motors relative speed and the gravity will throw away the Abort Motors in-flight without any Jettison Motor ...however (if needed) they can be smaller in the newLAS ...advantage: newLAS

    "spring mechanisms"..."the issue cannot be simply ignored": I don't ignore the problem (and spring may be a lighter alternative) ...advantage: newLAS

    ABORT MOTOR: since everything is smaller in my design (with, both, a standard or TBS Orion) the newLAS' Abort Motors will be smaller and lighter ...advantage: newLAS

    "no clear overall mass advantage to either design": that's may be true ONLY if the newLAS still needs heavy things like the BPC (but my design DOESN'T NEED it!) ...advantage: newLAS

    TPS PROTECTION PANEL: in my design I've (simply) joined the four (smaller) Abort Motors to the planned (but, so far, unknow) TPS protection cover/panel/structure (then, no extra-mass is added) also, other (much lighter) designs are possible ...advantage: newLAS

    "this panel cannot be jettisoned it must be carried to orbit": the standard-Orion design must already have "something" like it (to carry in orbit and to the Moon) then, it's weight already is in the standard/TBS weight account ...advantage: newLAS

    STABILITY: it's impossible to know which design is more stable (or needs more attitude jets' propellent) without MANY tests and REAL flights ...(small) advantage: unknown

    "my" Total Score is:

    Underside: 12

    Tower: 0

    Unknown: 1
    And the Winner is... "newLAS"! ...

    .
    Last edited by gaetanomarano; 2007-Feb-16 at 10:19 PM. Reason: grammar

  15. #375
    Quote Originally Posted by stutefish View Post
    ...TPS-panel-to-orbit...
    no, my design doesn't add any "extra-mass" to the (unknow, but planned) Orion-TPS protection cover/panel/structure
    ...the canard solution, while proven, requires an additional subsytem that is not required if the ACS performs the task...
    that's true (and don't forget the additional structure it needs)
    .

  16. #376
    Quote Originally Posted by Bob B. View Post
    ...one item alone may be enough to knock the underside system out of contention...
    as I've already explained in a previous post, I've added a "TPS protection panel" in my drawing ONLY to explain WHERE the Abort Motors can be joined, but my design doesn't add any further cover/panel/structure, since it (simply) will use the (unknown, but planned) Orion-TPS protection cover/panel/structure
    .
    Last edited by gaetanomarano; 2007-Feb-16 at 10:16 PM. Reason: bold

  17. #377
    Quote Originally Posted by gaetanomarano View Post
    NOSE CONE: my design MERGES the tower-LAS' Nose Cone, Adapter Cone and Attitude Control Motors in a single (smaller and lighter) module ...advantage: newLAS.
    Your nose cone alone is bigger and heavier; the other items are address elsewhere.

    ATTITUDE CONTROLS: smaller, lighter and merged with the Orion's nose cone ...advantage: newLAS
    The placement of your attitude control system is suboptimum and will therefore be bigger and heavier. There is no engineering justification to claim an advantage for the underside LAS.

    CANARD SECTION: it can be used only in a brief part of ascent and it's not indispensable, then deleted in my design to save on volume and mass ...advantage: newLAS
    The underside LAS probably gains a slight advantage on mass but loses on most other counts. If my life was the one on the line, I’d rather have the canard system working for me.

    INTERSTAGES: the three tower-LAS' intestages are unnecessary (and the SM doesn't need to be "resized" but just "reshaped") ...advantage: newLAS
    The mass of those three small interstages is miniscule. They appear to measure about 3 square meters in surface area at probably about 10 kg/m^2, for a total of about 30 kg. I was probably being too generous in calling this one even since the SM needs to be slightly enlarged and the extra wall openings reinforced.

    ADAPTER CONE: in my design it's merged with the Orion nose cone (that is smaller and more aerodynamic than the tower-LAS Adapter Cone) ...advantage: newLAS
    The deletion of the adapter cone does favor the underside LAS, but including this above with the nose cone was a transparent attempt to double-dip, claiming the same advantage twice to pad the score in your favor.

    BOOST PROTECTIVE COVER: my design doesn't need any giant and heavy BPC ...advantage: newLAS
    Wrong, the reasons for needing the BPC still exist with the underside LAS.

    JETTISON MOTOR: as real tests will show, the SM external shape, the SM/abort-motors relative speed and the gravity will throw away the Abort Motors in-flight without any Jettison Motor ...however (if needed) they can be smaller in the newLAS ...advantage: newLAS
    Acceleration will throw the abort motors directly aft, not outward. Jettison motors or some other mechanism will definitely be needed. Furthermore, the nose cone/ACS/BPC assembly requires a jettison motor.

    ABORT MOTOR: since everything is smaller in my design (with, both, a standard or TBS Orion) the newLAS' Abort Motors will be smaller and lighter ...advantage: newLAS
    Since everything is not smaller, your argument fails. There is no apparent advantage either way.

    that's may be true ONLY if the newLAS still needs heavy things like the BPC (but my design DOESN'T NEED it!)
    Denial noted.

    TPS PROTECTION PANEL: in my design I've (simply) joined the four (smaller) Abort Motors to the planned (but, so far, unknow) TPS protection cover/panel/structure (then, no extra-mass is added) also, other (much lighter) designs are possible ...advantage: newLAS
    There is no planned TPS protection panel as you show it. What you require is a means to attach the abort motors to the underside of the heat shield without penetrating the shield or otherwise compromising the TPS. There is simply no need for any such attachment and/or protection hardware with the tower LAS. This is undeniably an advantage to the tower LAS.

    "this panel cannot be jettisoned it must be carried to orbit": the standard-Orion design must already have "something" like it (to carry in orbit and to the Moon) then, it's weight already is in the standard/TBS weight account ...advantage: newLAS
    The SM probably has a forward bulkhead, but what you are proposing is clearly above and beyond anything needed for the tower LAS. And since the extra mass cannot be jettisoned, your proposal suffers a significant penalty.

    STABILITY: it's impossible to know which design is more stable (or needs more attitude jets' propellent) without MANY tests and REAL flights ...(small) advantage: unknown
    Stability is predictive based on know conditions and know principles – one doesn’t have to perform real flight tests to predict how a body will perform. In this case the indicators point toward the tower LAS being more stable.
    Last edited by Bob B.; 2007-Feb-16 at 10:47 PM. Reason: spelling

  18. #378
    Quote Originally Posted by Bob B. View Post
    ...your math is off a bit...
    you're right, but I've just made a (Abort Motors' propellent+10%) raw-calculation ...however, you can add 28 kg. to the newLAS weight
    ...if Orion is lightened then the tower LAS gets to be reduced in size as well...
    I've said that in my article and evaluated (both) standard and TBS Orion newLAS ...the reason of my comparison with the standard tower-LAS is that my goal is to save as much mass as possible from the current version
    ...the attitude control propellant...
    until new NASA specs better define this point, I suppose the "propellent mass" include the attitude propellent
    ...boost protective cover...
    unnecessary in my design
    ...jettison motors/mechanisms...
    unnecessary or minimal increase of mass
    ...TPS protection panel...
    already available in the standard Orion design, no new mass added
    ...SM structural modifications...
    minimal, not comparable to the weight saved with the newLAS
    .

  19. #379
    Quote Originally Posted by Bob B. View Post
    ...thus it may already have enough propellant without adding more...
    true, if the ACS has enough propellent for high altitude abort, has it also for lower altitude ...however, this is a full point for the newLAS since the risk/safety factor is possible, but (so far) just a guess/opinion of you
    ...nose cone/attitude control system will definitely require a jettison motor to push this assembly away from the vehicle during ascent...
    no, your evaluation about the payload penalty to carry the newLAS in orbit (for additional safety) is correct (despite it's possible with the 5-seg.SRB Ares-I max) since it misses the goal of payload mass' saving (to launch it with a smaller rocket) but this is not true with the NC/ACS, since it may weigh in the order of a few hundreds kg. (not so much, especially with the lighter TBS-Orion) and can be just detached (with the Ares-I 2nd stage) in the elliptical orbit (to decay and burn in the atmosphere) ...then, no extra-mass added (and another full point for the newLAS)
    .

  20. #380
    Quote Originally Posted by Nicolas View Post
    ...aerodynamic loads may require more performant engines...
    not necessary, since I'm quite sure that (both) ACS motors' power and ACS propellent's mass are already designed with large redundancy in the standard LAS
    ...btw...
    just a little question... "btw" is the acronym of...?
    .

  21. #381
    Quote Originally Posted by gaetanomarano View Post
    not necessary, since I'm quite sure that (both) ACS motors' power and ACS propellent's mass are already designed with large redundancy in the standard LAS
    The tower LAS has a significant advantage due to the longer moment arm. Your design will require larger thrusters and more propellant to achieve the same torque. If there is any safety factor or margin built into the tower LAS, your system will require the same safety factor or a proportionately larger margin to produce the same performance level.

    Quote Originally Posted by gaetanomarano View Post
    just a little question... "btw" is the acronym of...?
    by the way

  22. #382
    Quote Originally Posted by Bob B. View Post
    ...require larger thrusters and more propellant to achieve the same torque...
    assuming you're right, the real problem is not "if" but "how much" ...looking at the tower-LAS image, the ACS module is about 10% the volume of the Abort Motor, but, while the Abort Motor is full of solid propellent and has external nozzles, the ACS module works with liquid propellent and has its (more complex) liquid thrusters, systems and electronics INSIDE the module, so, the total ACS propellent mass of a tower-LAS may be in the range of 3-5% the Abort Motor propellent mass ...then, since (from NASA specs) the total propellent mass of a tower-LAS is 2.5 mT, the (redundant) ACS propellent mass is ONLY (around) 75-125 kg. for a standard-Orion and ONLY (around) 60-100 kg. for a (-15% resized) TBS-Orion ...well, assuming that my canard-less design will REALLY require 30% more ACS propellent to produce "the same performance level", the DRAMATIC increase of mass of the newLAS will result in a mere 37 kg. (for a standard-Orion) or only 30 kg. for a TBS-Orion
    .
    Last edited by gaetanomarano; 2007-Feb-17 at 12:01 PM.

  23. #383
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    Bob, thanks for the replies. Very interesting reading, as always!

  24. #384
    Quote Originally Posted by cjl View Post
    ...being intentionally obtuse...
    what I found very obtuse is your insist to "explain" me that obvious fact
    ...facing the 400C wind...
    despite its slower LEO reentry, the Space Shuttle faces up to 1260C on its TPS and wings, up to 650C sidewall and up to 370C in the less exposed areas ...since the peak temperature on the Orion's TPS will reach 2650C at reentry, we can evaluate its sidewall temperature (on the Orion's Hatch, Attitude Control Jets, etc.) around 1370C and the lowest reentry temperature in the less exposed areas (on the Orion's Docking Port and Parachutes' Outlets...) around 780C ...well, SIMPLE LOGIC says us that, if ALL Orion's vital parts (control jets, hatch, chutes' outlets, etc.) will be NOT damaged (but still work properly!) when exposed up to 15 MINUTES at up to 1370C or 780C at reentry (WITHOUT any BPC, Nose Cone or other protection!) the SAME parts in the SAME positions CAN'T BE DAMAGED if exposed (only) 20 SECONDS at (only) 400C (or 650C if you prefer) !!! ...then, the BPC is ABSOLUTELY UNNECESSARY without the tower-LAS and insist on want it is simply RIDICULOUS !!!


    PS - why do you have quoted my entire posts just TWO posts after the original? (quoting this way the thread becomes very long)




    .
    Last edited by gaetanomarano; 2007-Feb-17 at 02:57 PM. Reason: color

  25. #385
    Quote Originally Posted by Bob B. View Post
    And what exactly do you think "boost" is referring to?
    for my (not perfect) understand of english it sounds like the place that resist to / protect from the abort motor's thrust
    .

  26. #386
    Quote Originally Posted by Nicolas View Post
    ...the 400C is just a guess...
    assuming that your guess is correct (despite we don't know how much heat will hold/dissipate the REAL Orion) and the Orion on ascent flight will REALLY faces 400C on the external side (for about 20-30 seconds) we must know IF that external temperature (for that time) really IS dangerous (and may damage the capsule and its systems) or NOT ...well, despite I think that my post #384 already give a complete and definitive answer to this question, if you still have some residual doubts, I explain you again my opinion with an intriguing example...

    you know (and probably like) the Pizza... it's an italian food available, liked and popular all over the world and, in every country, it's made in hundreds different ways with traditional, local or exotic ingredients on its top... but the TRUE and ORIGINAL italian Pizza is the round Neapolitan Pizza Margherita made with "strong wheat flour, natural brewer's yeast, water, San Marzano's tomato, sliced buffalo mozzarella, basil and oil" that "must be baked for 6090 seconds in a 485 C (905 F) stone oven (below) with an oak-wood fire".

    well, despite the (small and fragile bread-like) Neapolitan Pizza Margherita is NOT made of a mix of strong layers, fibers and alloys of aluminium, iron, steel, titanium, molybdenum, tungsten, carbon, etc... after 90 seconds of cooking at 485C our Pizza is NOT liquified nor vaporized but just cooked at the "right point" to enjoy its best taste!!!

    then, a mere 400C of temperature for 20-30 seconds that Orion will face on ascent is NOT the DRAMATIC, TERRIFYING and DANGEROUS problem you claim, but (simply) 80% of the temperature and 1/3th of the time required to cook a good Pizza!!!

    ...unfortunately, if you put four uncooked Neapolitan Pizzas on the Orion's surface, when the astronauts will retrieve them in orbit (with an EVA) they can't eat them, since their Pizzas will still be half-cooked, because 400C and 20-30 seconds are just 80% of the temperature and 1/3th of the time to cook a Pizza...




    .
    Last edited by gaetanomarano; 2007-Feb-18 at 04:42 PM.

  27. #387
    Join Date
    Jul 2005
    Location
    Boulder, CO
    Posts
    3,471
    Quote Originally Posted by gaetanomarano View Post
    for my (not perfect) understand of english it sounds like the place that resist to / protect from the abort motor's thrust
    .
    This would be a large part of the problem then. Boost refers to the period of time during which the rocket is boosting through the atmosphere. During this period, high temperatures and large loads will be encountered, and although they are not as high as during reentry, they are still more than significant enough to require a protective cover, since the vulnerable upper surface of the capsule is being exposed to them.

  28. #388

    a new, better, simple and lighter version of the newLAS

    .

    since the Boost Protective Cover is CLEARLY UNNECESSARY in my LAS design, I've updated my newLAS article with a further good idea (and two new drawings) that uses the Orion's Attitude Control Jets reversed as newLAS Attitude Control System, so, the "merged" Nose-Cone/ACS is now unnecessary (then, deleted) and changed with a (very simple and light) Carbon fibers' Nose Cone

    thanks to this (further) good idea, the new total mass of my LAS may fall to only 2 mT (for a standard-Orion) or only 1.7 mT for a TBS-Orion!!!

    .

  29. #389
    Quote Originally Posted by Bob B. View Post
    ...nose cone alone is bigger and heavier...
    near ALL points of your post #377 and ALL residual critics against my newLAS are CLEARLY OVERCOMED by my newLAS article's update and my posts #384 and #386

    .

  30. #390
    Quote Originally Posted by gaetanomarano View Post
    since the Boost Protective Cover is CLEARLY UNNECESSARY in my LAS design
    Not if your capsule is, as you like to say, "Orion derived" because Orion requires a boost protective cover.

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