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Modification of Space Shuttle Tiles?

  1. Jul 28, 2005 #1
    Hello Lockheedmartin Space Systems
    Media Reps Jan Wrather
    (303) 971-5967
    Harry Wadsworth
    (504) 257-0094

    I wanted to ask drop by and ask a brief question for the engineers
    Lockheed Martin Michoud Assembly Center. Could the foam covering the
    shuttle external fuel tank be coated with a silicone seal similar to
    the type commonly used to coat roofs. The substance is water proof,
    lightweight, inexpensive and usually guaranteed to last 25 years Would
    have asked the engineering staff directly but don't know their email.

    Chris Walters

    Origional Question On modifying Shuttle
    Thermal Tiles

    1. Hello a website was set up to ask if it might
    be possible to modify the space shuttle thermal
    tiles or fuel tanks by interlacing and reinforcing the foam
    with titanium wire, kevlar, or some other


    2. If the idea is feasiable who would be contacted
    at NASA or the contractor?

    C Walters
    Last edited: Jul 29, 2005
  2. jcsd
  3. Jul 28, 2005 #2


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    Staff: Mentor

    Reinforcing the Shuttle foam with Kevlar mesh has been proposed. Don't know the status of that at the moment.

    I don't believe reinforcing the tiles with interlace wire is practical. Each tile is a wholly separate piece. There is slight gap to allow for thermal expansion. The apprpriate place to reinforce a tile is just below the surface - which is also the hottest zone during reentry. Any metal like Ti would melt or become very soft, and organic material would probably gasify.
  4. Jul 28, 2005 #3


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    I watched the show on Discovery a few weeks ago detailing the post-Columbia changes. They showed stuff the team was trying to develop to repair tiles and how the foam application was changed.

    I was very surprised that the foam application is a manual process, and when viewing cutaways of the foam on TV, each layer is inconsistent like it would be expected if a human were involved. So a kevlar mesh on the shuttle side to reduce debris to an acceptable size seems so easy it makes little sense why it isn't being used and a reduction applied to the payload capacity to offset the extra weight of the mesh.

    Also in regards to the tiles, the focus was on how to repair them once in space. I wonder if a computer simulation today could re-design the tiles so there would only need to be like 8 stock sizes of hexagonal tiles or something, so again the shuttle could carry up some replacements of each size and/or leave the extras on the ISS each time to create a stockpile of easily swapped replacements. At least then all they would need to do is re-examine the adhesion process of each tile and make that possible in space, I assume the adhesion layer is exposed to far less heat and only compressive forces since its protected by the tile. To me this seems far easier than designing a substance that can be applied in a space walk and survive re-entry heat.

    I dunno, it seems odd when so much effort is put into optimizing a design that potentially limits the overall success, but since they only seem to get budget cuts and not allocations, it makes more sense.
  5. Jul 29, 2005 #4
    Why does the foam on the external tank even need to be on the outside of the tank in the first place?
  6. Jul 29, 2005 #5


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    It is easier to fabricate and inspect with the foam on the outside. On the inside, there are the tank support structures and limited clearance between LOX and LH2 tanks and outside shell.

    When designing a complex engineered structure, manufactaring and quality control/quality assurance methods must be considered. Sometimes they dictate how something is designed, and sometimes these considerations are not trivial.
  7. Jul 29, 2005 #6
    according to national public radio's Science Friday
    the foam is predominantly for aerodynamic purposes
    it supposedly is a housing to hold cables in place during lift-off
    and to reduce drag over the whole section
  8. Jul 30, 2005 #7


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    I can't help wondering if de-icing the external tank immediately prior to lift-off might reduce stress on the foam enough to prevent it from breaking loose. It seems to me that the launch vibrations would be transmitted to the ice, which would then start tugging on the foam.
  9. Jul 30, 2005 #8
    Bid Process for NASA-Reply

    From: "hq-public-inquiries"
    To: "'Chris W'" <chrissaidthanks2002@yahoo.com>
    Date: Fri, 29 Jul 2005 17:45:48 -0400

    Dear Mr. Walters:

    Thank you for your inquiry to NASA.

    Under Federal regulation, NASA is authorized to accept technical proposals for evaluation only under one of two conditions: a proposal must either be (1) submitted in response to a formal competitive solicitation; or (2) presented as an unsolicited proposal. The procedure for submitting an unsolicited proposal is described in a NASA guidebook located at http://ec.msfc.nasa.gov/hq/library/unSol-Prop.html. The concept you describe is not structured as an unsolicited proposal as defined by the guidebook. Therefore, as submitted, it cannot be accepted for review. These rules are primarily intended to protect patent rights and copyright privileges of inventors.

    Also, included in the above Web site are the respective NASA Centers and their particular technical areas of responsibility under the section entitled, “NASA Research areas and addresses for submission.” Perhaps you can address your questions directly to the respective NASA Center for an expedited response. After you review that information, should you continue to believe that your proposal would be more appropriately aligned with an area of research associated with a particular NASA Center, please forward a valid unsolicited proposal directly to that Center. You are strongly encouraged to follow the instructions as outlined in the “Guidance for the Preparations and Submission of Unsolicited Proposals,” Web site so that NASA Center personnel can process and fairly review your proposal.

    NASA hopes that this information will be helpful to you as you pursue your goals. Again, thank you for your letter and interest in NASA.

    Public Communications Management Office
    NASA Office of Public Affairs
  10. Aug 2, 2005 #9
    Modification Shuttle System Assets

    Question Modification of Space Shuttle System[/br]
    Based on Improved Use of Existing Assets​

    This is a generic idea which NASA refers to as an unsolicted bid to improve the use of existing space assets to extend the life of the space shuttle system and improve safety. It is believed the existing system could be reverse engineered to create a system which has fewer complexities and would be stastically less likely to fail:

    #1 Replacement of Shuttle Outer Skin​

    1. The shuttle would be stipped of it's various outer thermal tiles to the inner aluminum skin

    2. A system of lightweight inner tiles would be place around the inner aluminum skin with an inner gasget of either silicone or other latex.

    3. An out skin of possibly of titanium or other high tensile metal would form the shuttle outer skin.

    4. We would need to create a small model to show the new configuration of outer skin of metal; inner layer of tiles; and inner layer of aluminium

    #2 Revised Mission Profiles​

    1. As the shuttle is basically a "space plane" it designed to spend most of it's time in orbit

    2. When not in use the shuttle is docked on an oribital pivot or triangle with the other shuttles for maintence; fueling; and other aspects of mission preparation

    3. Mission expendables are regularily lofted into orbit by what the Russians currently are experts at "big dumb rockets" which are reported to be magnitudes of order cheaper than shuttle launches and can easily include personnel and even science projects.

    4. If the Russians are experts in "big dumb rockets" ask the space partners to use their expertise on this facet of the operations.

    5. The shuttle would have to under go modifications to include docking devices on the wing tips; nose; under belly and probally under the tail to accomodate being moved by a remote space tractor.

    6. The shuttle revised program requires few if any travels to earth and has modifications to include refueling in space (details not explained here); ongoing maintence in space by a small resident crew.

    #3 Use of Cocoon​

    1. The Space Shuttle cocoon is an artifact which is lofted into orbit by "big dumb rockets" and designed to fit over the shuttle like a glove when it returns to earth.

    2. The cocoon is metal shaped in the form of the front and sides of the shuttle covered with a extra heavy amount of thermal protection.

    3. The space shuttle docks with the "cocoon" and attached by hard points in the nose; wing; and then then begins it decent

    4. The cocoon is designed to take all the heat of reentry while permitting the shuttle inside to use it's front thrusters; rear engine; and wing slats to manuver

    5. When the Shuttle has decended and slowed enough the cocoon is jetisoned by simply flying the shuttle upside down and backwards where air pressure will cause it to slip off

    6. The space shuttle then lands as it would normally

    #4 Discussion of Reverse Engineering​

    It seems plausible that many of the design flaws in the current space shuttle system were created in the 1970's when engineers tried to incorporate too many new and untried technologies. Reverse engineering and revision of the space shuttle mission profile means the vehicles spend most of their time parked in space instead of the in the hangar. The Shuttle would be used primarily to fly only on missions in space instead of making endless trips too and from the earth as a sort of low class ferry for shuttle crews.

    Attached Files:

    Last edited: Aug 2, 2005
  11. Aug 2, 2005 #10


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    Reduction is ice accumulation is what the new heaters are designed to do. Basically one has to prevent water vapor from condensing and then freezing in the shuttle insulaiton. IIRC, the insulation is porous, hence the problem of water vapor getting to the cryogenic lines and freezing.

    Ideally one would seal the outer surface of the insulation foam - but that might add mass, unless its a very thin laye. Alternatively, one only needs to seal the region adjacent to the LOX (and LH2) line. However, one issue would be any differential in deformation or shear forces as a result of the differences in properties of the adjacent surfaces.

    According to one report, the foam which broke off from ER-121 may have been affect during some repair.
  12. Aug 2, 2005 #11


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    FYI - a nice overview of the Shuttle's thermal protection system can be found at -Shuttle Thermal Protection System (TPS)




    From Lockheed -
    - from http://www.missilesandfirecontrol.com/our_products/spaceprograms/SHUTTLE/product-shuttle.html

    Another nice historical overview of the TPS - http://history.nasa.gov/sts1/pages/tps.html
    Last edited: Aug 2, 2005
  13. Aug 2, 2005 #12


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    Gold Member

    Very cool info, Astro! Thanks. I haven't been able to follow any of the proposed or incorporated modifications (time factors always work against me), so I was unaware of the heaters. As for moisture entry, could some kind of hydrophylic substance incorporated into the foam itself help? I'm thinking along the line of the silica dessicant sometimes found in medicine bottles or electronics packaging.

    One problem I see with your proposal is that you are essentially denying the shuttle its original role, which is to be a re-useable Earth to orbit transport. If the thing is going to be used exclusively for orbital work, it would be based upon a lightweight framework with enclosures for crew and cargo. You wouldn't have aerodynamic considerations, or re-entry heat issues, or anything else. You'd still need a regular Shuttle-type vehicle to return to Earth and get back up again. I think also that you're severely overestimating the Shuttle's aerodynamic manoeuvrablility when suggesting the method used to drop the 'cocoon'. The thing flies like a brick.
    Last edited: Aug 2, 2005
  14. Aug 2, 2005 #13


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    Sorry if side stepping a bit - I'm trying to get a grip on the overall criticality and performance of the RCC etc., have you guys come across anything which might enable one to carry out a simplified integrity assessment (or seen one reported somewhere)? Basically I'm thinking about fracture properties of the RCC, some mechanical info was given under links related to these threads.
  15. Aug 3, 2005 #14
    STS 1 & 2 flew with seal over foam

    Hello Danger: and thanks for you input. We learned that
    the process of sealing the foam was already flown on
    STS Missions #1 & #2 as cited further below.

    Astronuc certainly did have an excellent idea of placing
    stip heaters in a silicone or latex sealer around the

    The Cocoon or anyother proposed system if it could be designed
    and engineered would have to be tested in a wind tunnel on
    a model before it could actually be installed on the larger
    system. Consider Q-Goest previous estimates of $10,000
    a pound to lift materials into orbit and then consider the
    cost of lifting the shuttle into orbit 123 times. The
    billions in costs savings of leaving it in orbit might
    have paid for the costs of modifications and purchase of
    several more shuttle.

    I am somewhat new to physics forms and have made the
    mistake of having 2 similar conversations going on at
    the same time. Thanks again Danger-Chris

    Attn: Sandy Russo
    Code 210.H
    Goddard Space Flight Center
    Greenbelt, MD 20771
    Office of Space Flight Space Shuttle

    It appears that NASA already used and discared Fire Resistant
    Latex flown in STS-1 and STS-2 as described in the Book
    Space Shuttle by Dennis Jenkins (1996) Library Congress
    #9694309. On page 242 Dennis describes the ET Thermal Protection
    System to include ETC PR2488 & Ablatos MA 255 and SLA 220.
    The Fire Retartant Laxtes was removed to save 545 lbs and
    $15,000 of cost to external fuel tank.

    I making an unsolicited bid proposal I didn't realize the
    idea of using latex or other rubber composite protection over
    the foam system was already tried. Chris Walters

    Media Reps Jan Wrather
    (303) 971-5967
    Harry Wadsworth
    (504) 257-0094
  16. Aug 3, 2005 #15


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    I cannot accept credit for the heater idea - I was simply reporting what NASA/Lockheed has already done. NASA implemented heaters in the foam insulation.
    from NASA approves new design for Shuttle external tank fitting

    also -
    from http://www.nasa.gov/pdf/112315main_RTF_changes_pk.pdf



    PerennialII - I am sure Marshall or Langley have the properties of RCC. For example - Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Nose Cap
  17. Aug 15, 2005 #16
    Saving $165 Million per launch

    Hello Astro Nuc:

    Thanks for your most recent reply. I got a nice reply from Lockheed Martin
    which is shown below. Hope whatever they try they test it on a model in a windtunnel first.

    I also considered your figure of $10,000 a pound to life the 165,000 empty pounds of the shuttle into orbit at a cost of $165 Million. This goes
    back to the idea of enormous saving to leave the shuttles parked in space and use "big dumb rockets" to lift cargo into space as much cheaper.

    From: "Buddy Nelson" <buddynelson@mac.com> Add to Address Book
    Subject: Re: Submit Unsolicited Bid External Fuel Tank-Research
    Date: Tue, 2 Aug 2005 10:21:15 -0700
    To: chrissaidthanks2002@yahoo.com
    CC: "Michelle Brown" <michelle.a.brown@lmco.com>,
    "Jan Wrather" <janet.wrather@lmco.com>,

    Mr. Walters -- Thanks very much for your ideas on the shuttle
    external tank.

    As you know, despite the foam shedding at the PAL ramp and a couple
    other areas of concern, Discovery actually suffered 80% fewer "dings"
    than average during launch. Nevertheless, we are working closely with
    NASA to address and fix those few areas of the tank that remain

    We appreciate your suggestions.

    Best regards,

    Buddy Nelson
    Lockheed Martin Space Systems Company
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