SpaceDev presses on with Dream Chaser

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holmec

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This article says that they have allocated money to do a study on the engines of the Dream Chaser system. The step after that is to build and test the craft. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
 
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j05h

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Go Jim Go! (or your corporate descendants...)<br /><br />I like the Dreamchaser concept. It evolved from a plan to use the abandoned x-34 airframe as a testbed launcher. Take a mothballed, existing airframe and flight tested, awarding-winning hybrid motors and integrate into a new product. I don't necessarily think they'll be flying passengers in 2008, but the Dreamchaser could easily be the next manned spacecraft to fly. It also has the cachet of old-school NASA viewgraphs as a passenger ride, being the unfinished HL20. <br /><br />Two points, please. Unlike a whole lot of rocket companies, SpaceDev offers a working human-rated rocket that is surprisingly safe. Negatively, unless they intend on reverse engineering the airframe, they can only build one DreamChaser. I'm expecting that they'll will use the first one as a testbed and prototype, and design a new airframe later.<br /><br />What are your thoughts on reusing abandoned spacecraft? Is DreamChaser feasible? <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>
 
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holmec

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Well SpaceDev has proved itself in the space industry with satellites, components, and engines (SpaceShipOne).<br /><br />So I trust that they think they can do it and make it feasible. My question is who is going to charter it? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
 
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j05h

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Benson Space Company, a new Jim Benson project, is going to operate (and fund) the DreamChaser. SpaceDev will be the manufacturer.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>
 
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Boris_Badenov

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<font color="yellow"> My question is who is going to charter it? </font><br /><br /> I suspect after they have proven the design, they will offer them for sale. <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>
 
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j05h

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> I suspect after they have proven the design, they will offer them for sale.<br /><br />Yes, I listened to Jim Benson's recent interview at Rockets Away Media (via ITunes) and he said that Benson Space is priming the fiscal pump for SpaceDev. SpaceDev will develop the DreamChaser, sell the first one to BSC and then sell others to other operators. He also indicated that they will eventually use the DreamChaser for orbital operations, which the HL20 was originally designed for. He repeatedly said they won't change the CoG and aerodynamics of the craft due to the amount of engineering already put into the craft.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>
 
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holmec

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But to whom is BSC going to cater to? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
 
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j05h

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<i>> But to whom is BSC going to cater to?</i><br /><br />Space tourists, I'd imagine. Maybe some freefall and reentry research too. Not sure beyond the paying customers.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>
 
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Swampcat

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<font color="yellow">"But to whom is BSC going to cater to?"</font><br /><br />Probably the same people Virgin Galactic will cater to...i.e., those that can afford it.<br /><br />It will be interesting to see what kind of "package" BSC puts together. With VG, the $200k gets you more than a suborbital ride. Maybe BSC will dispense with all of the extraneous stuff and provide just the ride for a lower ticket price. <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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josh_simonson

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Well, virgin galactic envisions eventually going orbital with their spacecraft development. That's an opportunity for spacedev since Virgin is basically saying they intend to buy much larger engines. <br /><br />The dreamchaser spacecraft itself isn't that important compared to the boosters that will loft it.<br /><br />It's a bit silly to use hybrid engines all the way to orbit though, the ISP is low and payload fraction will be tiny. They may be better off using a big hybrid booster to get out of the atmosphere, then use a higher ISP stage for the rest of the burn.
 
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docm

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When you talk of hybrid ISP's being "low" are you talking HTPB and similar fuels or paraffin? Makes a big difference.<br /><br />Paraffin burns at surface regression rates that are 3 to 4 times that of conventional hybrid fuels, delivering a much higher impulse. <br /><br />Other recent patents improve this using dual-vortex injection of the oxydizer. <div class="Discussion_UserSignature"> </div>
 
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holmec

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>Well, virgin galactic envisions eventually going orbital with their spacecraft development. That's an opportunity for spacedev since Virgin is basically saying they intend to buy much larger engines.<<br /><br />Where did you get this info from? <br /><br />BTW Scaled Composites has an orbiter in its sites as well. So I'm curious if Virgin will stick with Scaled Comp. or get an orbiter elsewhere. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
 
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holmec

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SpaceDev article on Hybrid engine<br />"For a manned sub-orbital space plane, Isp and mass fraction are traded off for low-cost and high-reliability within the boundaries of acceptable performance and size constraints."<br /><br />SpaceDev pretty much do their homework. So second guessing what they are doing might be silly.<br /><br />As far as I understand it the Dreamchaser system is of 3 large hybrid boosters, 1 smaller hybrid booster, and then the engines inside the orbiter itself. I think their intent is to keep costs down and reliability up. If they went with higher Isp engine that seems to affect those stats. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
 
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josh_simonson

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It's more of a case of they're working with what they've got. It's break even if a cryogenic upperstage doubles the price of the vehicle, but also doubles the payload. The lack of a cryogenic stage also precludes any GTO missions, which are 90% of the current market.
 
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holmec

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The thing is this is for the manned commercial market. There is not current manned commercial market.<br /><br />Also their whole point is the cost and reliablility of hybrid. If they do it any other way they are undermining their own premise. <br /><br />Are you mixing apples and oranges? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
 
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josh_simonson

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Hybrid's relibility and performance are inferior to other cofigurations, such as pressure fed hypergolics and engine out configurations, otherwise NASA (who is happy to pay 10bln for a little extra safety) would be using hybrids on their LVs, SMs and LSAMs. <br /><br />Even if the engine has 100% reliability, there is still software, TVC and other things to go wrong.
 
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Swampcat

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<font color="yellow">"Hybrid's relibility and performance are inferior to other cofigurations, such as pressure fed hypergolics and engine out configurations, otherwise NASA (who is happy to pay 10bln for a little extra safety) would be using hybrids on their LVs, SMs and LSAMs."</font><br /><br />I think the jury is still out concerning the reliability and performance of hybrids. It's true that there is not enough of an experience base with large hybrids, but this is rapidly changing. SpaceDev is a leader in this technology. They might know something about this that you and I don't know.<br /><br />NASA doesn't use hybrids because they have the cash (i.e., tax payer dollars) to pay for bleeding edge technology, higher ISP systems. A government agency can afford to do that. SpaceDev is a business and must make a profit somehow.<br /><br /><font color="yellow">"Even if the engine has 100% reliability, there is still software, TVC and other things to go wrong."</font><br /><br />Some things are common to all propulsion methods. Those things can cause problems with liquids and solids as well. With all due respect, what's the point of bringing that up?<br /> <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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nyarlathotep

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<font color="yellow">Hybrid's relibility and performance are inferior to other cofigurations, such as pressure fed hypergolics and engine out configurations, otherwise NASA (who is happy to pay 10bln for a little extra safety) would be using hybrids on their LVs, SMs and LSAMs.</font><br /><br />Was this expert consensus made by the same group that thought putting hydrogen in a boosters first stage was a pretty neato idea?
 
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holmec

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>Hybrid's relibility and performance are inferior to other cofigurations<<br /><br />Performance yes, reliability no. At least according to SpaceDev who has done the experiments on them and applied them in a real flights. <br /><br />Look I understand that hybrids are not thought of well in the industry. But SpaceDev has done and is still doing the work and putting down the money to show the rest of the industry what is real with hybrids and what is myth. I applaud them for their pioneering spirit. Now lets see if they are right or wrong. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
 
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rocketman5000

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Funny some of the same people trashing hybrids are the same ones crying for a big dump booster. a large hybrid is very similiar to the large pressure fed liquid boosters that many want for the ultimate HLV.
 
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josh_simonson

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Supposedly the CEV SM will be able to do a return burn even if it's OMS engines fail because it's RCS engines can be used as backup with the same fuel. That's basically an engine out capability that dramatically increases reliability of the system as a whole. Hybrids, since half the fuel is in the engine, cannot possibly be used in an 'engine out' manner. If the igniter or oxidizer valve fails you are stuck.
 
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Swampcat

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<font color="yellow">"Hybrids, since half the fuel is in the engine, cannot possibly be used in an 'engine out' manner. If the igniter or oxidizer valve fails you are stuck."</font><br /><br />You're grasping at straws here. A liquid propellant propulsion system also has an igniter and oxidizer valves that could fail...another commonality between liquid and hybrid propulsion systems. Liquids have the additional possibility of a fuel valve failure...something hybrids <i>don't</i> have.<br /><br />Again, with all due respect, what is the point of mentioning this?<br /><br />BTW, in a hybrid, <b><i>all</i></b> of the fuel is in the combustion chamber. The other half of the <b><i>propellant</i></b> is the oxidizer. <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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spacester

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I've a question that didn't seem to merit its own thread, and this is as close as I've seen as a topic.<br /><br />I'm wondering about lunar operations using simple stockpiled paraffin rocket motors with local O2 (LUNOX) to get around instead of using water and electricity to make difficult cryogenic liquids.<br /><br />What are the possibilities for a paraffin/LOX hybrid? Been done much, or ever? The predicted Isp? Special design considerations? Long term storability would be excellent, correct? Any chance the casings could be made and filled on-site, allowing the stockpiled commodity to be the paraffin itself?<br /> <div class="Discussion_UserSignature"> </div>
 
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docm

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NASA Ames, Stanford and others have tested paraffin/NOX and paraffin/LOX, both very successfully. LOX's ISP is higher. Downside is the need for cryogenic stowage, valving etc.<br /><br />Another fuel option is plexiglass. Much lower efficiency, but fuel handling is drop-dead simple and cheap-cheap-cheap. <br /><br />Eldest son and I built a plexi/NOX test gadget last summer and didn't even use a combustion casing. We threaded the end of a 4" plexi rod, bored to a 1/2" chamber, and screwed it into a brass cap containing an .8mm carburetor jet (any auto parts store). No nozzle. A used "Sneeky Pete" auto NOX kit (10 oz) & a bit of custom plumbing completed the job. The igniter was a de-glassed auto dome bulb with a 3X Pyrodex/epoxy coating. <br /><br />Pyrodex is a smokeless black powder substitute used in black powder rifles, pistols and cannons.<br /><br />Noisy, bright (transparent combustion chamber) and very cool. Next summer a real paraffin for launch. <div class="Discussion_UserSignature"> </div>
 
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Swampcat

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<font color="yellow">"What are the possibilities for a paraffin/LOX hybrid? Been done much, or ever? The predicted Isp? Special design considerations? Long term storability would be excellent, correct? Any chance the casings could be made and filled on-site, allowing the stockpiled commodity to be the paraffin itself?"</font><br /><br />As docm said, paraffin/LOX is currently the most promising hybrid propellant combination. (See Candle wax is rocket science: Paraffin fuels test launch.)<br /><br />To add to what docm said, there are plenty of relatively cheap hybrid fuels. My hybrid motor uses an ABS plastic fuel grain. Many amateurs have built hybrid motors using PVC pipe as the fuel <i>and</i> the casing. Just about any hydrocarbon will work, with obviously a higher hydrogen content preferred. The question would be, what kind of hydrocarbon could be manufactured from in situ resources? Since most hydrocarbons are produced from petroleum (including paraffin) and there are no known petroleum deposits on the Moon, it's probably not going to happen. Maybe someone with a better knowledge of Lunar resources could add their thoughts here.<br /><br />I don't know what SpaceDev makes its casings out of, but my hybrid uses aluminum. IIRC, there's plenty of that on the Moon. <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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