Redesign the STS

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pmn1

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You have the chance of redesigning the STS but you have got to keep to the same basic configuration - central core, boosters (unless you can avoid them) and a winged return vehicle - what changes would you make to improve operations and any guestimates on changes (if any) to operating costs? <div class="Discussion_UserSignature"> </div>
 
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rocketman5000

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Enlarge the External Fuel tank and eliminate the foam. There is just too much thermal stress in the foam from the cryogenic temperatures to be able to keep if from cracking IMO. A larger tank would be able to make up for the fuel boiling off or maybe have a Liquid Nitrogen tank that would boil off to not sacrifice the Propellant. I realize this would probably reduce the standby time with current fueling strategies. <br /><br />maybe make the tank so that it has a resonance frequency close to the natural frequency of water so that the accumulated ice would be shaken off before the shuttle reached speeds that would cause damage if struck by the ice.
 
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rocketman5000

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Redesign the thermal protection system so that it required less maintence. the same with the SSME nozzles and combustion chambers. Currently both have to be polished on a fairly regular basis. I know that with certain technologies now available the inner layer could be made of a ceramic and the outer of the current material. A gradual disposition of near molten material to a mold allows 2 dissimiliar materials to be used without building up large internal thermal stresses that would seperate the layers.
 
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grooble

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Use a one use only attachable heat sheild and have it mass produced which will reduce turnaround time and maintenence costs.
 
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vogon13

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Ceramic lining to an SSME would be quite a trick. Anything that has insulating properties (like a ceramic compared to metal) in contact with the 6000 deg. F, 3000 PSI combustion gases will require more maintenance than what is currently done. This lining will produce interesting flares in the engine exhaust as it burns off. Also, heat absorbtion through the engine cooling tubes will be diminished (briefly) and upset the operation of the turbo pumps, too.<br /> <br /><br />Any material that would work in this capacity would be better employed on the RCC.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
 
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pmn1

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Different boosters, different placement of main engines (as in Energia/Buran?), external cargo bay?? <br /><br />I've seen an artists impression of an orbitter with an external bay - what, if any advantages would that have for the redesigned STS? <div class="Discussion_UserSignature"> </div>
 
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pmn1

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Additional edit......<br /><br />You cant have anything that wasn't around when the STS was designed... <div class="Discussion_UserSignature"> </div>
 
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craig42

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Assuming enough development money and time. Replace ET with a reusable stage.
 
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craig42

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Assuming enough development money and time. Replace ET with a reusable stage. Baseed on one of the alternate concepts considered before the current design was choosen
 
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propforce

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Make a liquid flyback ET and strap the SSME on the ET instead of on the Orbiter. <img src="/images/icons/cool.gif" /> <div class="Discussion_UserSignature"> </div>
 
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rocketman5000

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I didn't think about that, I don't believe the actual material I was thinking of was ceramic. Yes it would change the heat absorbation. Whatever the material was wouldn't have needed to be polished every launch. <br /><br />I ran across the information while reading about NTR's a long time back. It stated that this was needed to be able to reduce maintainence and to be able to recycle the engine many times on the Journey to and from Mars. Wish I could find it. It would be pretty difficult and expensive, but not impossible.
 
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rocketman5000

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That would definately help with the return to Earth. Removing the engines would make less weight that the TPS would have to absorb on the return and further reduce weight. <br /><br />The major drawback, besides the safety record of playing Russina Roulette. Is the amount of maintenence needed after every flight. It is hard to say what I would redesign without seeing the economic impact. Many of the systems work wonderfully. SSME for example.<br /><br />An expendable heat sheild that is ablative would be more ideal IMO. Making the airframe from a composite that has a longer fatigue life and can withstand higher temperatures could eliminate a large amount of the TPS in the cooler sections.
 
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pmn1

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Would there be a case for reducing the payload capacity of the orbitter but keeping the ovearll booster the same size - how often was the full capacity used in a manned launch that couldn't have been handled by an unmanned cargo pod (if there was one)?<br /><br />I acknowledge that would be difficult given the booster size would be dependant on the orbitter size but could you successfully argue a case of 'future proofing'? <div class="Discussion_UserSignature"> </div>
 
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scottb50

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I would use the STS components in a two stage to orbit vehicle. The first stage would use four SSME's, two hybrid, fixed, SRB's, using Shuttle nozzles, and two turbo-fans. The second stage would be carried externally, like the Shuttle. Various payloads attach to the second stage for delivery to LEO. <div class="Discussion_UserSignature"> </div>
 
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ace5

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launcher- Two liquid-fuelled boosters working on kerosene/LOX.<br />ET without foam, aluminum skin instead.<br /><br />orbiter - Two jet engines for cross range manouvering upon return
 
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scottb50

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You are throwing away payload, kerosene has less energy than Hydrogen. I'm not talking about an ET with foam either. The first stage is self contained Modules with an outer aerodynamic, non-structural shell. <br /><br />orbiter - Two jet engines for cross range manouvering upon return.....<br /><br />I've been thinking more along the lines of a Lear Jet 40 series. For launch it is covered by a fairing and taken to a LEO Station by the upper stage. Modification to the Lear would add a Docking Adapter and improve the pressure vessel sealing, but would be pretty simple. <div class="Discussion_UserSignature"> </div>
 
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pmn1

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From what i've read, there were disagreemnets between the payload capacity of the orbitter NASA wanted and the payload capacity of the one the USAF wanted - would there be a case for two types of orbitters, a smaller in-line on for NASA and the larger historic side mounted on for the USAF but using as many common parts as possible?<br /><br />What would be the cost implications of this? <div class="Discussion_UserSignature"> </div>
 
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pmn1

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There is an article by Stephen S Pietrobon (Small World Communications) in the May/June 1999 Journal of the British Interplanetary Society about replacing the SRB’s with LRB’s<br /><br /><font color="yellow">The use of high-density hydrogen peroxide/kerosene liquid rocket boosters for the Space Shuttle is investigated as a replacement for the existing SRB’s. It is shown that H2O2/Kerosine outperforms solids, LOX/Kerosene and LOX/LH2 as a general booster propellant due to its high density and moderate exhaust speed. With the same propellant mass and size as that of the current SRB’s, computer simulations indicate payload mass can be increased by a third from 24,950kg to 33,140kg for a 28.45°, 203.7km circular orbit.</font><br /><br /> Hi,<br /><br />AndyMc on Nasaspaceflight.com has found a complete PDF of the article.<br /><br />Just googled, and found the article you mention is availabe as a pdf: http://www.sworld.com.au/steven/pub/lrb.pdf<br /><br />His site may also have some more things of interest: http://www.sworld.com.au/steven/ <div class="Discussion_UserSignature"> </div>
 
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lampblack

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<font color="yellow">From what i've read, there were disagreemnets between the payload capacity of the orbitter NASA wanted and the payload capacity of the one the USAF wanted - would there be a case for two types of orbitters, a smaller in-line on for NASA and the larger historic side mounted on for the USAF but using as many common parts as possible?</font><br /><br />Yes... the biggest improvements would likely stem from eliminating the devil's deal that NASA struck with the Air Force and building a smaller shuttle.<br /><br />A smaller ship with liquid fueled fly-back boosters --done correctly, it would likely have come much closer to achieving the goals of true reusability and low-maintenance.<br /><br />In other words: if NASA had been allowed sufficient development money up front, things would have been very different. The shuttle would have been smaller and more capable -- and so much less of a disappointment in terms of cost and crew safety.<br /> <div class="Discussion_UserSignature"> <font color="#0000ff"><strong>Just tell the truth and let the chips fall...</strong></font> </div>
 
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pmn1

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If the main engines had been ET mounted from the start, would it have been possible to introduce recovery and re-use that was economic compared to just throwing them away along with the tank? <div class="Discussion_UserSignature"> </div>
 
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nyarlathotep

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The first thing you'd want to redesign out of the STS is the management bureaucracy. That's been the major problem with the shuttle from day one.
 
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rocketman5000

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The limiting factor in the amount of heat composites can handle is the expoxy resin. Carbon Graphite can indeed handle high temperatures. Carbon-Carbon composite is a testiment to this. <br /><br />Matweb.com reports that the melting point of aluminum is 660 degree C or 1220 degree F. The metal is going to lose structural integrity at a much lower temperature that that. Burt Rutan's Spaceship one constructed almost entirely of Composites reached up to 500 degree F or about 260 degree C. I couldn't find any information of the maximum operating temperature of aluminum, but that would depend largely on operating conditions such as internal and external stresses.
 
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rocketman5000

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shuttle_guy<br /><br />"Removing the engines from the Orbiter is agood idea, just as the Russians did, however that wight removed from the aft of the vehicle would have to be replaced with the same amount of ballast unless the wing design was changed. The Center of Gravity of the Shuttle Orbiter MUST be in the same place as it is today or the Orbiter is unstable. " <br /><br />Obviously the aerodynamic design would have to be reexamined. The transonic region of stability is very critical to any machine that travels supersonic
 
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brandido

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Thanks - that is effin' cool. Wonder if, after the November 25th launch of the Falcon 1 NASA would consider working with SpaceX to work on a design to strap some of the Falcon-9s to the Shuttle in place of the SRBs <img src="/images/icons/smile.gif" />
 
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