Challenger Class Shuttle System

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willpittenger

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Shortly after Challenger was destroyed in 1986, I began thinking of what became my concept for a next-generation shuttle system. Years later, I started thinking of this system as the Challenger class. I hope that within 20 years a real system that capabilities described in this document becomes reality. I know that this isn't ready for production. Some of the requirements probably require tomorrow’s technology. However, I hope technology will catch up with me before that 20 years is up. As a result, perhaps it would be better to think of this document as a set of specifications. Correctly implemented, I think this could become the first truly economical fully reusable single stage to orbit system available.<br /><br /><br /><b><font color="black">Early concepts prior to the name be associated my proposed system</font>/b><br />Prior to my entry into college in 1990, I mainly had two versions of this concept, which I kind of blurred together. It too some time before I really considered this something I wanted to see happen. The first version was since the Rogers Commission linked the SRB booster to the explosion, I started insisting that no rockets be required. (I realize now that at least something equivalent to the RCS system on today’s shuttle would be needed. As for orbital maneuvering, I had hoped that ion engines would be enough. Again, I have no information on that.) Therefore, I asked my high-school physics teacher if an airplane going fast enough could leave the atmosphere. Shortly after he said yes, I heard about the X-30. That was the second version of the concept.<br /><br />I started looking at the X-30 design. I thought I saw several problems with it. First, I couldn’t understand how the X-30 would fly at speeds significantly below Mach 5. It didn't have enough wing area. The fuselage could help, but not with the scramjets in the way. It took me a while to figure a solution out.<br /><br />Second, by then, I had heard about a type</b> <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>
 
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qso1

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Interesting idea, of course, an SSTO that takes off from a runway is the holy grail of access to LEO and this is one of the best features I can see with this idea, plus reusability. In addition, you have definetily put a lot of thought into it.<br /><br />willpittenger:<br />Don’t ship your satellite to me – I will come pick it up<br /><br />Me:<br />This is a great business idea but one that will require some investment in facilities and maybe customers building satellites that are not so reliant on laboratory and clean room processing.<br /><br />willpittenger:<br />We are probably talking about the highest gross maximum takeoff weight ever to fly.<br /><br />Me:<br />You bet, the AN225 was the only aircraft I'm aware of to exceed 1 million pounds and it was and may still be the heaviest to fly unless the new Airbus 380 is heavier.<br /><br />Some issues you may want to address:<br /><br />Theres really no reason from a safety standpoint not to use rockets as they still have a very high reliability rate. When one tries to eliminate a percieved safety issue, another will replace it. Veteran shuttle watchers would clap their hands at post Challenger launches when the SRBs separated. I always preferred to save the celebration for post landing and Columbia eventually bore this reasoning out. Your system could become operational and maybe years later have an accident resulting from something completely unanticipated.<br /><br />I know of only two aircraft types never to have a hull loss accident. The B-2 bomber (God forbide one of them ever crashes) and X-29.<br /><br />Ion propulsion builds up small amounts of thrust over long periods of time in current systems and they are not effective at all endoatmospherically if memory serves me.<br /><br />willpittenger:<br />Under normal conditions, several days would be allowed. However, please note that turnarounds are much faster when there is no stack or requirement to make the vehicle vertical.<br /><br />Me:<br />Actually, most of a shuttle orbite <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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willpittenger

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<blockquote><font class="small">In reply to:</font><hr /><p>Some issues you may want to address:<br /><br />Theres really no reason from a safety standpoint not to use rockets as they still have a very high reliability rate. When one tries to eliminate a percieved safety issue, another will replace it. Veteran shuttle watchers would clap their hands at post Challenger launches when the SRBs separated. I always preferred to save the celebration for post landing and Columbia eventually bore this reasoning out. Your system could become operational and maybe years later have an accident resulting from something completely unanticipated.<br /><br />I know of only two aircraft types never to have a hull loss accident. The B-2 bomber (God forbide one of them ever crashes) and X-29.<p><hr /></p></p></blockquote><br />I know some of that know. However, I still would prefer to end up on a suborbital trajectory with the scram jets alone. Fewer components needed.<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>Ion propulsion builds up small amounts of thrust over long periods of time in current systems and they are not effective at all endoatmospherically if memory serves me.<p><hr /></p></p></blockquote><br />I know. I kind of touched on that.<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>If your using the airframe to generate lift, the landing gear bumps could be a problem.<p><hr /></p></p></blockquote><br />I do not understand you. Those bumps would only need to protrude an inch or two if the structure is strong enough.<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>BTW, got any illustrations of this vehicle?<p><hr /></p></p></blockquote><br />I am not an artist. You have to settle for drawings in my head. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>
 
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qso1

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willpittenger:<br />I know some of that know. However, I still would prefer to end up on a suborbital trajectory with the scram jets alone. Fewer components needed. <br /><br />Me:<br />Good idea, but if your not using rockets at some point, what kind of propulsion system takes you to orbit?<br /><br />willpittenger:<br />I do not understand you. Those bumps would only need to protrude an inch or two if the structure is strong enough.<br /><br />Me:<br />Without a drawing, I had envisioned bumps like on the C-5 which protude down a foot or so. If these only extend down an inch, do you really need them?<br /><br />Thanks for the drawing, that helps me understand it a bit better. If you play around a bit more with your paint program, you'll get the hang of how to do an illustration and you will need that when presenting your design. I noticed you were able to make circles. You can make something like a square just to represent your fuselage or whatever main structure is utilized. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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willpittenger

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<blockquote><font class="small">In reply to:</font><hr /><p>Good idea, but if your not using rockets at some point, what kind of propulsion system takes you to orbit? <p><hr /></p></p></blockquote><br />I had envisioned the scramjets providing enough thrust for that before they run out of oxygen. The rockets would be used to convert the resultant suborbital trajectory into a true orbit.<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>Without a drawing, I had envisioned bumps like on the C-5 which protude down a foot or so. If these only extend down an inch, do you really need them? <p><hr /></p></p></blockquote><br />I wanted something to cope with the unevenness of the pavement. Other than that, the more I look at it now, no. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>
 
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qso1

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willpittenger:<br />I had envisioned the scramjets providing enough thrust for that before they run out of oxygen. The rockets would be used to convert the resultant suborbital trajectory into a true orbit.<br /><br />Me:<br />That sounds workable. Its been so long since I looked at any specs of previous attempts at SSTO. I think they had a similar scheme planned for NASP but thats been almost 2 decades ago. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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willpittenger

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New stuff:<br /><br />* I seriously doubt that aircraft will ever exceed Mach 27. As you go faster, it will be tougher and tougher to remain in the atmosphere. This is the simplest way for a plane-type orbiter to reach space.<br /><br />* For a higher orbit, if you can maintain a lower altitude while still going Mach 25+, do so. Once you have sustained that speed for a moment, begin a steep climb. The steeper, the better. By the time the scramjets can no longer support combustion due to lack of oxygen, you are on a suborbital trajectory. If you succeed in putting enough energy into the trajectory, you could fire your OMS-equivalent and stabilize it at your apogee. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>
 
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danwoodard

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Skylon is perhaps the most detailed concept of this type that has some engineering credibility. It was proposed by Alan Bond of Hotol fame and would use a cooled-inlet airbreathing engine (rather than the originally proposed liquid air cycle) up to about Mach 5, then shift to rocket propulsion. <br /><br />http://www.reactionengines.co.uk/<br /><br />http://www.geocities.com/CapeCanaveral/Launchpad/6133/skylon.html?200611 <br /><br />It appears workable but of course funding for a prototype is so far lacking.
 
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willpittenger

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Which of the two profiles I mentioned would they use? Would they settle for the barely orbiting trajectory (prior to the OMS firing) or the high suborbital trajectory I mentioned? <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>
 
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willpittenger

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New change:<br /><br />I remembered how the exhaust port (called aerospikes) for the X-33 was supposed to optimize airflow regardless of the outside air pressure. I decided it would be a good idea to have a similar design on a scram jet. Same layout. The only change changing from the X-33 layout would be the part in from of the exhaust port. I figure more thrust would be available from a scram jet with this exhaust port.<br /><br /><br />Other new comments:<br />* Scram jets should prove to be tough to pump fuel to. The faster you are going at any given altitude, the more oxygen will be flowing through the engine. More oxygen in the engine means you can pump more fuel and expect it to fully burn. More fuel burned results in more thrust. Hence, ignoring drag, the faster you go, the faster you <i>can</i> go until you can no longer pump fuel faster. Taking drag back into account, you are still limited by your ability to cool the hull, but since most fuels for scam jets would need to be preheated, that is partially solved. Only the sheer effect of the drag itself would be a problem. (The faster you go, the more drag there is.)<br /><br />* I assumed that most missions with the standard orbiter (with full support for crews) would omit the crew entirely if none were needed. However, pilots would be on board any crewed mission just in case.<br /><br />* The mission Commander should **not** be in charge of the vehicle. The Commander might not even be a pilot. Rather, the vehicle commander would be the emergency pilot. The Mission Commander overrules the vehicle commander except when orbiter safety is in question. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>
 
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willpittenger

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Qso1, your images for your book (shown in http://uplink.space.com/showthreaded.php?Cat=&Board=missions&Number=462981&page=0&view=collapsed&sb=5&o=0 and the replies to that post) impressed me. Do you have enough information to create similar images of a Challenger class orbiter?<br /><br />I would suggest showing it in each of the following:<br />* Taxiing along the runway<br />* Gear retracted up against a building to load cargo<br />* Pitch maneuver during takeoff<br />* In sub or super sonic flight<br />* Hypersonic flight<br />* Several in orbit (Docked at a station, working on cargo, etc) <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>
 
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willpittenger

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Perhaps rather than retracting the gear 100%, just bring them in enough to lower the hull to almost contact with the pavement. Would that solve your concerns? I would no longer need the bumps.<br /><br />If the bumps did survive, they could possibly all be located along the centerline or wing roots -- none of which attempt to generate lift. The rakes also must fold so they could help support some weight. (If they did not fold, they would prevent the vehicle from getting close to the ground. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>
 
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qso1

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Thanks, glad you like my stuff.<br /><br />I'm working a project for a client right now but maybe we can work something out in the near future. Those images I posted are my 3D images. In your case I would probably start with 2D (Paper drawing or paint program drawings) which can easily be changed as needed before committing to a 3D build which would take longer and I go to 3D when my own designs are finalized.<br /><br />BTW I would have to charge you for the service. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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