Shuttle Design/ Build 101

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craigmac

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Ever since the SkunkWorks Venture program tanked; as a replacement for the Space Shuttle, I’ve thought about combining the technologies of AreoSpike/ Scramjet engines propulsion. Since both technologies took off after during World War II there has been some confusion as to jet propulsion which use air intake to provide lift; rocket propulsion which most carry its own oxygen supply, and scramjet which theoretically has now moving parts. A good example of this Jet Propulsion Laboratory which today really doesn’t have much to do w/ jet propulsion research, but instead rocket science.<br /><br />I'd like to generate some feedback about combining AreoSpike/ Scramjet technologies, and design/ build concepts for a single stage space shuttle….<br />
 
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najab

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><i>Ever since the SkunkWorks Venture program tanked; as a replacement for the Space Shuttle...</i><p>X-33/Venture Star was <b>not</b> a Shuttle replacement. Combined (sc)ramjet-rocket engines are probably the only way to be Single Stage to Orbit work, but I suspect that the payload delivered to orbit will be too small for a Shuttle replacement.</p>
 
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erauskydiver

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Would you run the scram jets and aerospikes at the same time? You'd need something to get going fast enough to make the scramjets work. <br /><br />Then, what do you do with the scramjets after you have gotten out of the atmosphere? If you carry them, they are just useless dead weight. If you drop them, you are no longer an SSTO spacecraft.
 
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najab

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Well, in theory the (sc)ramjet and the rocket engine would be one and the same.<p>You get the vehicle up to ramjet speeds using some kind of ground launcher. Once the ramjet is burning you use it to get up to scramjet speeds, morph the intake and nozzle appropriately, and continue up to the edge of the atmosphere. When you've extracted all you can get out of the atmosphere, you close it air inlet and start injecting LOX into the combustion chamber (morphing the nozzle as required) to get you up to orbital velocity.<p>So, in theory, there are no droppable parts nor any deadweight. <img src="/images/icons/smile.gif" /></p></p>
 
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nacnud

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That sounds like a jobs for Sabre! <img src="/images/icons/smile.gif" /> again from the Skylon webpage.<br /><br /><b>The Sabre Engine</b><br /><br />In the past, attempts to design single stage to orbit rockets have been unsucessful largely due to weight of an oxidiser such as liquid oxygen. To reduce the quanitity of fuel that a vehicle is required to carry it is (one possible solution) useful to be able to use atmospheric oxygen in the combustion process. The Sabre engine does this, allowing two mode operation - both airbreathing and conventional rocket type operation. This is made possible througha synthesis of elements from rocket and gas turbine technology.<br /> <br />The design of Sabre evolved from liquid-air cycle engines (LACE) which have a single rocket combustion chamber with associated pumps, preburner and nozzle which are utilised in both modes. LACE engines employ the cooling capacity of the cryogenic temperature of the liquid hydrogen fuel to liquify incoming air prior to pumping. Unfortunately, this type of cycle necessitates very high fuel flow.<br /><br />These faults are avoided in the Sabre engine, which only cools down the air to the vapour boundary and avoids liquifaction. This allows the use of a relatively conventional turbocompressor and avoids the requirement for an air condensor.<br /><br />The Sabre engine is essentially a closed cycle rocket engine with an additional precooled turbo-compressor to provide a high pressure air supply to the combustion chamber. This allows operation from zero forward speed on the runway and up to Mach 5.5 in air breathing mode during ascent. As the air density falls with altitude the engine eventually switches to a pure rocket propelling Skylon to orbital velocity (around Mach 25).<br /><br />Air collection is via a simple conical two shock inlet with a translating centrebody to maintain shock-on-lip conditions. The centrebody moves forw
 
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rogers_buck

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Just as an interesting thought exercize, what about an updated airframe based on the Shuttle or Buran? For example, would the use of composites make any significant difference? Would titanium leading edges with coatings replace the tiles? From operating the shuttle for 20+ years have taught us anything we could apply to a new design that would greatly simplify the turn around times?<br />
 
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nacnud

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I would love to see what could be done with an updated shuttle but keeping the launch system compatible with the current system.<br /><br />Evolution not revolution.<br /><br />Some of the important considerations that I would like to address are the Air force requirements for cross range and the enormous amount of servicing needed between launches. A removable/palletized cargo hold may also be able to speed up servicing but to be honest I don't know as much as some on this board but perhaps a thread on redesigning the shuttle would complement the Gemini X3 thread. <img src="/images/icons/smile.gif" /><br />
 
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mrmorris

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<font color="yellow">"I would love to see what could be done with an updated shuttle but keeping the launch system compatible with the current system."</font><br /><br />I've always been of the opinion that the Shuttle concept was originally valid, and was hobbled by cost overruns/cuts and design compromises made for political reasons. However, the more I've done research in support of the Gemini-X3 thread, the more I become convinced that the concept was seriously flawed from the very beginning. <br /><br />Throughout the research I've been doing on the X3 -- it's a recurring theme that design and operations of the capsule are so incredibly much simpler than that of the orbiters. Just a single example -- each orbiter contains about 150 miles of wiring. With power and electronics centralized in the nose, the X3 would require on the order of 50 feet.<br /><br />The realization of just how flawed the shuttle concept was crystalized when I made a scale diagram of the orbiter and original Gemini capsule. It's huge! Even if you ignore *all* of the maintenance problems and costs associated with the shuttle -- <b>every</b> time it goes into orbit -- all of that dead weight must be lifted. I can't believe that anyone knowledgeable who saw the plans in the design phase ever believed that this was going to be an economical system.<br /><br />Just a few stats on the Atlantis orbiter from Astronautix:<br /><br />Total Mass: 104,328 kg. <br />Total Propellants: 21,600 kg<br />Total Payload: 24,990 kg. <br /><br />Every time the sucker goes up -- it's carrying ~126,000 kg of dead weight and can only carry a fifth of that as cargo. Even if the orbiters could be turned around and flown the next day with zero maintenance -- they still wouldn't be economical.<br /><br />The manned capabilities of the shuttle need
 
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kmarinas86

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http://64.233.167.104/search?q=cache:_wO6cgsERTcJ:media.nasaexplores.com/lessons/03-063/5-8_1.pdf+volume+of+gemini+cubic&hl=en<br /><br /><font color="yellow">Background Information<br /><br />The three cluster modules of Skylab enclosed 347 cubic meters (12,250 cubic feet) of space. This was more than 150 times as much as a Gemini spacecraft, and nearly 60 times the Apollo command module. Over two-thirds of this was the orbital workshop, where the crews would eat, sleep, and do much of their work. Early spacecraft had been designed to be functional, not lived in. Weight and volume limitations in the Mercury and Gemini capsules were designed for the bare requirements for protecting and sustaining life. Michael Collins, pilot on Gemini 10, compared the two-man Gemini craft to the front seats of a Volkswagen. That tiny space was home for Frank Borman and James Lovell for 14 days on Gemini 7. The Apollo command module, though just over twice the volume of Gemini, was still primarily a functional spacecraft. Some improvements made it a bit more pleasant (for example: it had hot water). The extra space gave the crew of three some freedom to move around and exercise stiff muscles, but it was anything but comfortable. For the most part, astronauts accepted whatever discomforts were in their spacecraft unless they interfered with performance. <b><i>What mattered most was accomplishing the missions.</i></b> A man on his way to the Moon could tolerate quite a lot of minor inconvenience. Teacher Sheet(s) Page 2 of 3www.NASAexplores.com</font>/safety_wrapper>
 
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drwayne

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Note that Skylab, due to its nature as a rocket stage, had a lot of space that was not really usable - empty space.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>
 
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halman

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mrmorris,<br /><br />I have to wonder if you are considering design requirements to be design flaws. The idea of a lifting body with enough wing area to allow gliding is inherently more complicated than a ballistic rentry vehicle with no terminal guidance, just as a solid bullet is much simpler than an armour-piercing high explosive round.<br /><br />The original design concept of the space shuttle was for a vehicle about the size of the current shuttle, with a small payload capacity, which was carried to an altitude of about 20 miles by a fly-back booster. The fuel contained in the body of the orbiter would be adequate to boost it into orbit.<br /><br />This was to be a prototype design, to prove the concept of using a lifting body in rentry, as well as the ability to land on a runway. The engineers who came up with this concept were well aware of the advantages and drawbacks of capsules, and they wanted something better. Because the purity of this original vision was ruined by the realities of the time, we have developed a very prejudiced view of this type of vehicle.<br /><br />We will probably see a return to a capsule design for the next manned space vehicle. We will also see a return to systems to protect the crew during lannding, such as ejection seats, and/or retro rockets, or air bags, to slow the capsule from the velocity it will attain while being lowered by parachute. We will also see a return to large recovery forces standing by for mobilization during landings, which will have to be carried out in unpopulated areas.<br /><br />Ultimately, if space flight is indeed to become common, the lifting body/glider design will almost certainly return, as it is the only known method of allowing a returning spacecraft to land on a runway at a designated location. This type of vehicle may never be suited to carrying bulk cargo, and may have to be used in conjunction with step rockets which do the heavy lifting. Launching vertically from the ground is also likely to g <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>
 
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mrmorris

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<font color="yellow">"I have to wonder if you are considering design requirements to be design flaws. "</font><br /><br />Actually I would be suggesting that the logic behind making the design a requirement was flawed. <br /><br />- Combining cargo and crew in the fashion that the shuttle does has serious downsides. <br />- The design was touted as being an economical means of getting cargo to orbit, not as a <i>'prototype design, to prove the concept of using a lifting body in rentry'</i>. The shuttle would not be economical way of getting cargo to orbit even if it were maintenance free between flights.<br />- The elements of the shuttle which allow it to return to a controlled landing are numerous, complicated, and heavy. The wings, control surfaces, hydraulics, APUs for the hydraulics, etc. all combine to make the shuttle much more complex and heavy. All of this must be lifted to orbit every time the shuttle goes up, and only has value on its return.<br /><br /><font color="yellow">"We will also see a return to large recovery forces standing by for mobilization during landings, which will have to be carried out in unpopulated areas. "</font><br /><br />Are you aware of just *how* primitive the controls were on the Gemini/Apollo on re-entry? The landing forces were huge because the landing footprints were huge because the landing controls bit the big one. A modern capsule armed with an INS/GPS and a computer which could calculate something on the order of ten million times faster than the Gemini/Apollo computers <b>and</b> control the thruster firings without human intervention should reduce the landing footprint by a couple of orders of magnitude -- even if it uses straight parachutes rather than a parafoil. If the landing zone is three square miles rather than three hundred square miles, then huge recovery forces are not required. Consider the Genesis sample return capsule and how close they were able to pinpoint the landing (OK -- crashing)
 
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pathfinder_01

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I don’t like to get into the wing vehicle vs. capsule debate. I personally prefer winged vehicles as they can land on a runway and be easily towed back to a hanger for maintenance. I also suspect that the engineering behind making something reusable that lands on a runway might be easier than something that splashes down in the ocean or lands or uneven ground. I am not adverse to parafoils, but juzz the x-38’s parafoil was pretty darn complicated.<br /><br /> I don’t think that combining cargo and personnel is the biggest flaw of the shuttle. I think the biggest flaw was the lack of specialized vehicles to suit a purpose and the lack of development. The shuttle really is a first of a kind and NASA over promised in order to get funds. If a new shuttle were created using modern materials and the insight NASA has from the current shuttle it would probably be cheaper to run. I like the view the shuttle like the Wright flyer. A first of a kind with lots of room for improvement. <br /><br />Launching a shuttle for a simple crew exchange is overkill. Using the shuttle to launch cargo increases the risks to the crew and unfortunately until the creation of the ISS the shuttle was mostly used as a pseudo space station. <br /><br />I think a shuttle like vehicle would be handy. The shuttle can not only haul cargo into space, but bring it down also. I view the shuttle as a pickup truck, handy for doing construction and repairs. I also think that having a small lifting body type craft able to exchange crews and perhaps a shuttle-C for lifting heavy cargo would complete the system. <br /><br /> I personally do not trust NASA’s math when it comes to using EELV. The EELV will have to be man rated and who knows how that will affect costs. The EELV will also have to be repurchased after each flight which again might quickly add up to not much cheaper than the shuttle. In the end I think the CEV concept might be cheaper, but not the orders of magnitude cheaper that NASA wants and NASA w
 
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Swampcat

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<font color="yellow">"We need a crew-cab pickup AND we need an 18-wheeler."</font><br /><br />I want the sport coupe model. <img src="/images/icons/cool.gif" /> <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>
 
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drwayne

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Wouldn't that be a Gemini - heck, it even had gull wing doors!<br /><br /><img src="/images/icons/wink.gif" /><br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>
 
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mrmorris

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<font color="yellow">"I don’t like to get into the wing vehicle vs. capsule debate. "</font><br /><br />In my mind, it's actually more an issue of relative complexity rather than lifting vs. non-lifting. In general -- the more complex something is, the larger, heavier, expensive and failure prone it is. The X-38 is a good case in point. It was designed for essentially the same role I envision Gemini X3. However -- where G-X3 will be about 4200-5000 kg -- the X-38 was supposed to weigh in at about three times that. When you're lifting that much more mass to orbit to perform the same role -- it's going to be less cost-effective unless there are some *huge* offsetting advantages.<br /><br /><font color="yellow">"I personally prefer winged vehicles as they can land on a runway and be easily towed back to a hanger for maintenance. "</font><br /><br />The Gemini-X3 is light enough to be transported by a heavy-lft cargo helicopter (like the CH-54. There is at least one company (quick Google search) which charters out services of this nature for several purposes -- including lifting timber from logging operations to sawmills. I didn't check on prices -- but if it's economical to lift a bunch of logs out of the woods -- the cost can't be too unreasonable. So even if we assume a parachute/desert rather than a parafoil/runway landing -- the X3 lands out in the Mojave, and is air-transported to a hanger. This seems easy enough.<br /><br /><font color="yellow">"I also suspect that the engineering behind making something reusable that lands on a runway might be easier than something that splashes down in the ocean or lands or uneven ground. "</font><br /><br />Are you aware that one of the original Gemini capsules was reflown? This despite having been landed in saltwater and *not* having been designed with reusability in mind (and using 1960s tech)? Suspicions without supporting evidence or despite evidence to the contrary mean very little.<br />
 
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marcel_leonard

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I'm thinking in terms of the SABER engine which combines principles of both rocket/scramjet. This would in the long term reduces weight/cost of delivery...<br /><br />The reason that alot of skeptics think that a single stage is too exspensive; is because the only thing they have to compare it to is the current shuttle design. If we are going to make deliveries affordable we will have to re-engineer shuttle design to incorporate a few of the following items [ie. aerospke, scramjet, carbon composite materials, new aerodynamics, and upgrade shuttle HW/SW intel.] <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>
 
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craigmac

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If take a look at the specs for the XRS-2200 linear Areospike engine , and research the firing test done it at Huntsville AL, and you would realize that this is yet another technological golden egg that NASA is just going to sit on. <br /><br />Think of all the unused NASA technology; over the past 35 years, and ask yourself if you would even know what the internet was if the PC industry worked the way NASA bureaucracy works? <br />
 
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craigmac

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<font color="orange">nacnud-<br />The Sabre engine is essentially a closed cycle rocket engine with an additional precooled turbo-compressor to provide a high pressure air supply to the combustion chamber. This allows operation from zero forward speed on the runway and up to Mach 5.5 in air breathing mode during ascent. As the air density falls with altitude the engine eventually switches to a pure rocket propelling Skylon to orbital velocity (around Mach 25). </font><br /><br />Are there any plans for utilizing some of this technology on the shuttle?
 
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nacnud

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Not really, the flight profile is all wrong. For an air breathing concept to work it has to spend a large amount of time in the atmosphere breathing oxygen and building up speed, before a rocket finally makes the last push to orbit. <br /><br />Rockets as we currently used them need to stay relatively slow in the atmosphere to reduce max Q (maximum aerodynamic pressure) and max heating to acceptable levels. Travelling fast in the atmosphere has lots of problems and currently the technology to deal with them is mostly untested or in its infancy.<br /><br />Personally I think that while SSTO (single stage to orbit) air breathing concepts win the glamour stakes TSTO (two stage to orbit) utilizing conventional rockets are likely to be much more achievable for the near future.<br />
 
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