Dream Chaser new design

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spacy600

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New Public Spaceship Design to be Unveiled<br />Author Leonard David<br /><br />Look for space entrepreneur, Jim Benson, to announce a fresh approach in the design of the “Dream Chaser†space tourism vehicle. The new suborbital design will be based on a melding of the NASA and Air Force X-2, X-15, and T-38 vehicles - rather than using the orbital NASA HL-20 lifting body craft.<br /><br />A five month-long study by SpaceDev and Benson Space Company has determined that this new design will provide “the first, safest and best astronaut-making spaceflights for the emerging space tourism market.†The announcement is slated to occur during the National Space Society’s International Space Development Conference that gets underway this week in Dallas, Texas.<br /><br />This new design is deemed safer and more aerodynamic. It will also allow Benson Space Company to remain on schedule to make its initial commercial spaceflights in 2009.<br /><br />The new Dream Chaser spaceship design is lighter and sleeker, Benson will report, resulting in less drag and requiring less propulsion than the earlier design. The vehicle, powered by safe hybrid rocket motors, will launch vertically and glide to a landing at the launch site.<br /><br />A safer “carefree reentry†after achieving an altitude of at least 65 miles, Benson will report, will subject passengers to minimal G-forces, compared to other designs. It will also have many large, well-placed windows for ideal passenger views of the Earth and space during the suborbital trek.<br /><br /> http://www.livescience.com/blogs/2007/05/24/new-public-spaceship-design-to-be-unveiled/<br />
 
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spacelifejunkie

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Thanks Spacy, great post! I am jacked to see how the Dreamchaser is going to turn out. The DC is the most flexible of all the designs out there. Sub-orbital, orbital, moon shot re-entry, it all can work with minor design changes. Flying by 2009 does seem like a stretch but I'll give them the benefit of the doubt for now. Late 2006/early 2007 has been a little quiet on space business. SpaceX had a nice launch (almost 100%) but other than that only minor updates. I have a feeling that once ISDC is over, the second half of 2007 and 2008 will ramp up quite a bit. Armadillo, SpaceX, Virgin Galactic, Masten, Spacedev, and now Benson Aerospace have been making lots of promises with hardware only a little bit successful. If everything stays on pace, 2009/2010 is going to be fun. Good luck to all and keep up the good work.<br /><br /><br />SLJ
 
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docm

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Since this is a <i>suborbital</i> tourism design the next logical question is do they still have orbital aspirations and if so is the HL-20 still the source platform? <div class="Discussion_UserSignature"> </div>
 
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gunsandrockets

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<Since this is a suborbital tourism design the next logical question is do they still have orbital aspirations and if so is the HL-20 still the source platform?><br /><br />I for one am not encouraged by the latest news. I don't see this substitute for the HL-20 having orbital potential. This winged rocket-plane reminds me of a glorified X-1 more suited for the x-prize.<br /><br />I strongly suspect the core reason for the design switch was to get in on the suborbital market as quickly and cheaply as possible. SpaceDev must be feeling pressure. <br /><br />I thought SpaceDev was smart to use the HL-20 as a suborbital vehicle that could eventually be used as an orbital craft. The new vehicle is a detour rather than a shortcut to orbit. Too bad.
 
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spacelifejunkie

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Can they do both? Will the HL20 derivative get put on top of the ATLAS 5 for ULA? I don't mind if they change the design toward the end if it gets to sub orbital space quicker but not at the expense of going orbital and beyond. I'm betting ULA will not want this new DC on top of their rockets.<br /><br /><br />SLJ
 
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gunsandrockets

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<...Also the lifting body is not suitable for high speed entries from the Moon. ><br /><br />Not suitable?? Please justify.<br /><br />The Lockheed-Martin engineering team which won the Orion CEV contract thought the opposite about lifting bodies.
 
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nyarlathotep

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<font color="yellow"><br /><...Also the lifting body is not suitable for high speed entries from the Moon. /><br /><br />Not suitable?? Please justify. </font><br /><br />I guess NASA is worried that under the reduced G load the astronauts would fall asleep?
 
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spacelifejunkie

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They are planning both!!<br /><br />"Determined to stick with the company's original operational concept, Benson and his team decided to start with a "clean sheet" design and put off development of the HL-20-based rocket."<br /><br />http://www.space.com/adastra/070526_isdc_entrepreneurs.html<br /><br />Although putting off the HL-20 design may delay it more than all of us would like. Maybe with ULA's backing and a COTS contract in the future it will put some more pressure on the make the orbital version happen sooner.<br /><br /><br />SLJ<br />
 
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gunsandrockets

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<The large surface area that would have to be covered by TPS would add too much weight making it an un-desirable configuration.><br /><br />Is this a generalized opinion, or is there a specific vehicle and a specific TPS mass for reference? <br />
 
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gunsandrockets

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I was asking for a specific example, not a restatement. I assume you have no specific examples with numbers attached for direct comparison? Then general concepts it is.<br /><br />There are a wide variety of ballistic and semi-ballistic capsules. As a capsule shape changes for increased hypersonic L/D, the difference in TPS coverage with a lifting body starts to shrink. The stubby cone shape of the Apollo capsule with a 0.35 L/D isn't very efficient compared to capsules with even lower L/D. A flat bottomed half-cone or wedge shaped lifting body isn't too bad in comparison to Apollo and has much better L/D.<br /><br />It all depends on the tradeoffs. An Apollo capsule shaped RV may have less TPS for the same volume, but such a capsule would also undergo much higher g loading. That might not be a problem for lunar return, but return from Mars could run as high as 16gs in an Apollo-shaped capsule. Ouch!<br />
 
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nyarlathotep

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<font color="yellow">A lifting body has a larger surface area to be protected from re-entry heating than a vehicle with a heat shield over a minimun surface area... Structure and TPS add additional weight</font><br /><br />Has anyone told NASA this? Their current vehicle needs <b>TWENTY</b> square metres of tps.
 
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