Specifications for the Dragon Capsule

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Boris_Badenov

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SpaceX has redone their website & added these specs for the Dragon. There is also a video available on this page.<br /><br /> DRAGON OVERVIEW <br /><br /> <br />--------------------------------------------------------------------------------<br /><br /><font color="orange">The Dragon spacecraft is a pressurized capsule used for Earth to LEO transport of either pressurized cargo or a crew of up to 7. Initiated internally by SpaceX in 2005, Dragon will be utilized to fulfill our NASA COTS contract for demonstration of cargo re-supply of the ISS.<br /><br />The Dragon capsule is comprised of 3 main elements: the Nosecone, which protects the vessel and the docking adaptor during ascent; the Pressure Section, which houses the crew and/or pressurized cargo; and the Service Section, which contains avionics, the RCS system, and other support infrasturcture.<br /><br />In addition a Trunk Section is included, which provides for the stowage of unpressurized cargo and will support the solar panels providing power to Dragon. The Dragon design is based on a traditional re-entry capsule with an ablative heatshield, an offset center-of-mass and a lift-to-drag ratio of ~0.3 during re-entry.<br /><br />Dragon Highlights:Fully Autonomous with Manual Over-ride capability in crewed configuration <br />Pressurized Cargo/Crew capacity of 3100 kg to ISS orbit <br />Supports 7 passengers in Crew configuration <br />Down-cargo capability (equal to up-cargo) <br />Integral CBM, with LIDS or APAS support if required <br />Designed for Water Landing under Parachute (Ocean Recovery) <br />Lifting re-entry for landing precision & low-g’s <br />To ensure a rapid transition from cargo to crew capability, the cargo and crew configurations of Dragon are almost identical, with the exception of the crew escape system, the life support system and onboard controls that allow the crew to take over control from the flight computer when needed. This focus</font> <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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gunsandrockets

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"SpaceX has redone their website & added these specs for the Dragon."<br /><br />Woah. Get this next bit...<br /><br />"In addition a Trunk Section is included, which provides for the stowage of unpressurized cargo and will support the solar panels providing power to Dragon."<br /><br />That's a big change compared to previous descriptions of the Dragon. Note how the updated images no longer show the old 'mickey mouse' solar panel array which used to be deployed from the nose.<br /><br />If the solar panel array is now deployed from the 'trunk' area two very interesting things strike me. <br /><br />First off the Dragon is now almost a carbon copy of the old BAE study for a multi-role capsule. The BAE capsule was a 4 meter diameter conical capsule with nose docking, a standard crew of 4 (up to six by removing cargo), RCS/thruster propellant and avionics in the rear of the capsule, nose mounted RCS/thrusters, and a reentry L/D ratio of 0.3. The BAE capsule also had a small expendable service module with cold gas thrusters, high gain antenna and a single solar panel.<br /><br />The second thing that strikes me is -- if the solar array is now in the trunk then it is going to get expended along with the rest of the trunk, just like the BAE capsule. The trunk covers the heat shield and has to be jettisoned for the capsule to reenter the atmosphere. I guess SpaceX has given up the idea of full reusability. The change is really a sensible design choice.
 
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Boris_Badenov

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<font color="yellow"> "In addition a Trunk Section is included, which provides for the stowage of unpressurized cargo and will support the solar panels providing power to Dragon." <br /> </font><br /><br /> I think you're right, & I didn't notice that before because I didn't look at the images, just the video & it shows the old Micky Mouse ears. They must have made it before they decided on the change.<br /> Anyway, here's a couple of pics.<br /> This one shows the separate sections & the trunk. <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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Boris_Badenov

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And reentry. This shows a good view of the ablative shield that had been covered by the service section & the trunk. <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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docm

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Dragon: 8 passenger LEO only<br /><br />Lockheed CTV/PTV: 8 passenger, but limited to LEO? Maybe not. <br /><br />It's based on planetary probe re-entry systems and combined with a Bigelow hab & a lander.... <div class="Discussion_UserSignature"> </div>
 
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soyuztma

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SpaceX has posted some new images of the Dragon on their website: Photo Gallery. The mickey mouse ears are gone. And the last picture of their photo gallery is of a Merlin 1C firing.<br />The Dragon page also has an interesting comment: "All systems designed to support long durations in space, including potential lunar fly-by missions". The Falcon 9 Heavy should have enough power to put the Dragon on a lunar fly-by trajectory. <div class="Discussion_UserSignature"> </div>
 
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Boris_Badenov

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Thanks for the heads up. <br /> I wonder what neccesitated the change from the Mickey Mouse ears to the more standard solar panels? Maybe it is the expanded capability? <br /> I'm really interested in seeing an animation of the lunar reentry profile. I wonder if they hit the atmosphere just once & reenter, or if they aerobrake once, complete an orbit then reenter on the second pass. IIRC that gives them more opportunities for return flights. <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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gunsandrockets

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"I wonder if they hit the atmosphere just once & reenter, or if they aerobrake once, complete an orbit then reenter on the second pass."<br /><br />Since the Dragon lands on water, probably just a single direct entry.<br /><br />But, if the Dragon was going to do an Orion style skip re-entry the Dragon would be a safer capsule to do it in. The Orion capsule only has a RCS with 50 m/s delta V which means almost no ability to adjust it's trajectory between skips. Unlike the Orion, the Dragon capsule does not have a severable propulsion module; the Dragon's thrusters and propellant are built in giving it considerable ability to adjust trajectory between re-entry skips.
 
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docm

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So now the question has to be asked; <br /><br />if CTV and Dragon can do lunar return re-entry profiles with larger crew compliments and, in the case of at least Dragon, better RCS control WTF do we need Orion for? <div class="Discussion_UserSignature"> </div>
 
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Boris_Badenov

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I rather doubt that Dragon will be able to carry 7 crew to the Moon. More likely only 3. <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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docm

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If 4 it ties Orion, and you can bet it'll be cheaper. That leaves Orion one major advantage; ground touchdown. <div class="Discussion_UserSignature"> </div>
 
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R1

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great , thanks for keeping us posted!<br /><br />Im so glad we're making progress on vehicles<br />designed to be capable of lunar trips <div class="Discussion_UserSignature"> </div>
 
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Boris_Badenov

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<font color="yellow"> If 4 it ties Orion, and you can bet it'll be cheaper. </font><br /><br /> Even if it is only 3, it'll be magnitudes cheaper than Orion. 10 Falcon9 launches will be cheaper than 1 Orion/Ares launch. <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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gunsandrockets

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"So now the question has to be asked; if CTV [??] and Dragon can do lunar return re-entry profiles with larger crew compliments and, in the case of at least Dragon, better RCS control WTF do we need Orion for?"<br /><br />The fact the Dragon has an Apollo level l/d of 0.3 opens up possible lunar missions. So yes, the Dragon is a threat to the Orion even though the Dragon is a smaller capsule in which a crew of 2 or 3 would be more practical than an Orion size crew of 4.
 
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docm

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<font color="yellow">gunsandrockets: CTV [??]</font><br /><br />CTV/PTV = the Atlas launched capsule Lockheed was talking about last spring and again this last few weeks in regards to its possible cooperation with Bigelow. Said capsule is based on its planetary probe re-entry system. <div class="Discussion_UserSignature"> </div>
 
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gunsandrockets

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"CTV/PTV = the Atlas launched capsule Lockheed was talking about last spring and again this last few weeks in regards to its possible cooperation with Bigelow."<br /><br />Ah. So many acronyms to keep track of these days. Thanx.
 
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