SpaceX Dragon

[radarredux]

> <i><font color="yellow">A new class of Air Traffic Controllers will be needed !</font>/i><br /><br />Space Traffic Controllers (STC).</i>

 

[radarredux]

> <i><font color="yellow">Wander how t/space (CXV) is taking this news?</font>/i><br /><br />I was thinking the same thing. SpaceX's design looks an awful lot like the CXV, minus the fact that the docking is on the front instead of the back.</i>

 

[josh_simonson]

>Initial designs for Dragon were somewhat similar to a blunt nose version of the DC-X - complete with landing legs. Driven by additional thinking - and the emerging demands of a cargo and human transport business for the ISS - the design of Dragon has been modified and the crew capsule portion of the spacecraft now sports a more conventional blunt conical, capsule-like design with a 15-degree slope angle. <br /><br />From http://www.spaceref.com/news/viewnews.rss.html?id=1095<br /><br />Sounds like it'll work the same as the CEV except the sidewall angle is less and it's smaller. The blunt nosecap may contain the parachutes, otherwise it'd have to do a 180 in the air to land on it's 'bottom' so that it doesn't land on it's nose and then fall on it's side.

 

[tap_sa]

<font color="yellow">"the docking is on the front instead of the back."</font><br /><br />Anybody else thinking that the swinging nosecap has to be quite heavy in order to have to cg close enough to the tip? t/Space CXV can have all sorts of equipment there but in this design there's just the nosecap, CBM and access tunnel.

 

[frodo1008]

That is fine if you have no sense of ethics, and are not caught. Otherwise, it is known as fraud, and is indeed frowned on by the feds!

 

[frodo1008]

It IS NOT yet developed, what he has are plans and basically a mock-up at this stage. I am not saying this isn't good in itself, but it is far from a finished ready to launch system! <br /><br />Quite possibly why Elon Musk has announced it at this point is to hopefully obtain NASA funding. This type of work is NEVER as cheap as some would like to believe it could be. And so Elon is bowing to realities here, which I personally think is good. <br /><br /> He has come to the realization (look at the Falcon I difficulties) that this isn't like starting up some kind of internet service! You have to deal with temperatures, pressures, and the severest environment possible. You can't deal with this with a software fix (as important as good software is), you have to have really hard hardware. And this is expensive. Cutting metal to the correct dimensions is VERY expensive, I know this to be true as that was the kind of thing I either actually did myself, or inspected the work of people that did such work. <br /><br />You MUST have the finest machines and NC (Numerical Control) programmers and machinists that good middle class wages and benefits can buy! Otherwise, you are just fooling yourself. Even the newer technologies of carbon fiber manufacturing require very good NC programming and good people to run the actual processes here. <br /><br />I sometimes wonder how many of the: rah, rah, go, go types on these boards have ever actually worked with these problems? Certainly, Elon Musk is beginning to find out! And it is to his credit that he is being truthful about the problems involved. <br /><br />Don't get me wrong here, I really don't care who puts mankind into space. I would be just as happy to have it be spacex as Boeing and LM, and even NASA itself. No problem there, I just think that a little bit of reality is a good thing.<br /><br />Let us hope that spacex can get the Falcon I off to a successful launch before we go on to the stars! <br />

 

[egom]

Frodo, good point here! Very few people on this board have a clear idea what means to build a complex product (software or hardware). And I feel that there are people that never worked one day in their life - and those are the ones that bash NASA the most. After you do a project on your own then your image about these things change.<br /><br />I am confident that Elon will fly his hardware. The guy has a track record, and the track record says that he does not fail. <br /><br />EgoM

 

[comga]

"Quite possibly why Elon Musk has announced it at this point is to hopefully obtain NASA funding. "<br /><br />Uh, yeah. COTS proposals were due last Friday. He said he is competing for more than half of their COTS funding, but less than the total.<br /><br />On the direction of reentry, several people were confident of different answers. Yes, if it comes in nose first, the seats have to turn around. t/Space showed a nylon sling verson of just such a seat. Does anyone have a real good reason, like CG or other stability driver that would point to one direction or the other? (We have seen no illustration of the interace between the capsule and the SM, which may or may not have a heat shield.) It does look a lot like t/Space's nose-first capsule which is based on extensive heritage.<br /><br />Also, Musk said, with what may be some exageration, that all Dragon lacks is an attitude control system and a heat shield. Besides the environmental system, which he discussed, I wonder what else he has in there. It seems like a heck of a lot more than a "mock up".

 

[trailrider]

"Also, Musk said, with what may be some exageration, that all Dragon lacks is an attitude control system and a heat shield. Besides the environmental system, which he discussed, I wonder what else he has in there. It seems like a heck of a lot more than a "mock up". "<br /><br />Engineering mockups can take many forms and can include or exclude components or systems that aren't required for the purpose of the mockup. For example, there is probably NO NEED for the RCS to be included if the purpose of the mockup is for internal layout of the crew cabin. "All" you have to do is paint (or even use a felt marking pen) on the outside of the vehicle where the RCS thrusters will eventually be. Neither do you need the heat shield to be simulated, and it is probably a LOT cheaper to build the mockup without the complex curve shape of the shield, especially if the mockup is sitting on the hanger floor. Musk may not even be planning to design the RCS system "himself" (SpaceX), but may sub-contract the job to another, more experienced outfit. Of course systems integration will be required, as it will with the heat shield, whatever the design. The heat shield design may be sub-ed out as well.<br /><br />So far as keeping the Dragon proprietary, and having it leak out, that happens in competing companies in an industry. Even if NASA provides funding, that is not necessarily a bar to commercializing the Dragon. After all Boeing developed the 707 in parallel with the KC-135.<br /><br />The Falcon I launch delays are more a result of logistical problems brought on by the shift from VAFB to the Pacific. USAF essentially screwed them over with the range schedule and availability. That's understandable as national security concerns have to come first. But it might have been better if that had been worked out first. SpaceX might have been able to have located a more convenient launch facility. The first launch of the Falcon I may fail... Hopefully it will be successful. But this

 

[no_way]

Other COTS participants are making their submissions public too: http://hobbyspace.com/nucleus/index.php?itemid=1102 <blockquote><font class="small">In reply to:</font><hr /><p>The Apex service features a family of mission-configurable spacecraft capable of achieving orbit on several families of launch vehicles. Through a patent-pending spacecraft design initiated over one year ago, SPACEHAB's Apex spacecraft have the ability to ferry equipment and other payload to orbit, rendezvous with and berth to the International Space Station and dispose of or return equipment and experiment results. Apex is designed to evolve to support human transportation, as needed, following space shuttle retirement.<p><hr /></p></p></blockquote>

 

[josh_simonson]

>The heat shield design may be sub-ed out as well.<br /><br />I doubt this. They're planning to recover the second stage of the falcon 5 and 9, which obviously involves a heat-shield. Probably they'll use a proven material, but I can't see them sub-contracting the heat shields for all their second stages and capsules. Very, very few re-entry capsules are built anyway, a heat shield of any sort isn't simply an off the shelf thing. <br /><br />I'd expect them to perfect their re-entry shielding with the larger falcon upper stages (the loss of which would be marginal), then apply the proven system to the capsule.

 

[mlorrey]

Well, for the record, I've developed products that I designed, set up manufacturing, brought them to market and dealt with the real economics of manufacturing and sales.<br /><br />One thing I found was that when I needed a high-technology, the best producers of that technology were often more expensive, but the lifetime of the technology was necessary to make the price/performance work. That was a plus. <br /><br />On the negative side, I found engineers who were petty. One, who ran the engineering dept at one of my suppliers, had developed a competetive product at another company years before, and was peeved that my product outperformed his, and stalled the development for months, until I got a VP from the parent company to go in and kick his ass into gear.<br /><br />Then what he and his aerospace engineers did was to overbuild it in order to make it too expensive. Rather than build the design I specified, they redesigned it with totally unnecessary features for ruggedizing that were beyond the standards for our industry. I refer to this behavior as "putting on the bells and whistles".<br /><br />Some engineers see overengineering something as a means of job security, some do it to stall out a project or kill it off financially.<br /><br />I'm not the only engineering type in my family. My father was an engineer at a large firearms manufacturer. One of the problems he found was that the polishing department, which polished all parts, operated as a defacto union, since they were a production choke point. They stymied and sabotaged all attempts at automating their work. Other workers ignored production step instructions, doing things their own way that caused quality problems and large amounts of scrap.<br /><br />These are just some of the issues one runs into. <br /><br />And still I bash NASA.<br /><br />It appears Elon has a good crew that knows what it is doing and still is learning from mistakes and oversights. This is to be expected. The difference between SpaceX and NASA i

 

[gunsandrockets]

"The yellow bits are unpressureized cargo in a disposable cyclinder. "<br /><br />Interesting idea, but I don't think it's so. Since the vehicle docks via the nose, cargo placed in the back end would end up going nowhere. I think the diagrams show that for cargo missions, cargo is placed inside the capsule in the same area as the crew berths.<br /><br />I believe the boxy structures in the rear of the capsule are the parachute containers.

 

[gunsandrockets]

"I am starting to think that a nose first entry might cause too many problems. Perhaps I was wrong."<br /><br />The nose must have some part in reentry, otherwise why keep the nose-cap after launch? But I think you are right about the problems of a pure nose first style reentry such as the t/Space CXV capsule is planning to use.<br /><br />The Dragon looks awfully crowded to use the same spinning seat trick as the CXV. Plus the main hatch and windows of the Dragon would be too exposed to reentry heating with a nose first attitude. Then there's the exit problem. I think SpaceX plans on water landing for the Dragon, just as they plan for water landing of the Falcon booster rockets. A nose first landing would place both the nose hatch and side hatch of the Dragon under water! The t/Space CXV, which also uses water landing avoids this problem with a tail-end main-hatch.<br /><br />So keeping these problems in mind, this is how I think the Dragon will recover. Instead of reentering nose first (or tail first) the Dragon will reenter sideways, functioning as a simplified symmetric biconic shape (just like the Delta-Clipper). The CG is located down towards the feet of the crew and the side main hatch (relative to the crew, right above their heads) remains in the lee of the reentry airflow. Once the Dragon slows to low-subsonic speed the parachute is deployed from the open ended cylindrical tail.<br /><br />I'm not sure if the Dragon would then descend nose down towards the ocean, but I think it will to more easily absorb the shock of contact with the water. After bobbing in the water a bit, the Dragon will stabilize, because of it's weight distribution, in a sideways attitude with the main hatch topside and the nose hatch partly underwater. This will allow the crew to easily exit without flooding the vehicle and ease recovery of the Dragon at sea since it could be towed nose first through the water like a boat.<br /><br />

 

[nacnud]

<font color="yellow">Since the vehicle docks via the nose, cargo placed in the back end would end up going nowhere.<br /><br /><font color="white">The unpresserized cargo would be removed via the SSRMS, pic from spaceref</font></font>

 

[j05h]

>The nose must have some part in reentry...<br /><br />Guns- I like your analysis, but tend to disagree. I think SpaceX is going with the simplest solutions for Dragon, which would be base-first reentry. If they want to keep it super-simple, they'll use an ablative, molded and cured resin-based heatshield. There are plenty of materials that can handle it now. The capsule they've shown has pretty tight confines which would make "flipping" seats troublesome. The nose and sides of the cone don't look like there is a heatshield there. Keeping the nose-cap on the capsule would protect the very valuable CBM from atmospheric damage and saltwater. It might contain the parachutes (doubtful?) or approach hardware (lidar or vid).<br /><br />The stack looks to me like this: base-first capsule, small service module (featuring the quads and tanks in graphic), and an open storage structure that doubles as interstage framework. Not sure where the LES is fitted, maybe they light the second stage if there's low-altitude trouble? That would leave the RCS for handling high-alt separations?<br /><br />I like your analysis, esp. the simplicity of water-based handling. It could still reenter base-first and have an inflatable segment near the base that orients it for water towing.<br /><br />Cool gear.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[j05h]

>They plan to use the service module engines for an abort (as discussed earlier in this thread). I would think they have 3 engines in the SM and would use all 3 for high acceleration on aborts but use only one during on orbit operations.<br /><br />Is the service module where I described it, between capsule and interstage? If so, are the 3 engines poking through the middle of unpressurized cargo? Or would it use the quads for all thrusting (combing RCS and OMS)? <br /><br />Do you agree that it reenters base-first? Which orientation otherwise?<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[nacnud]

Cartoons with an engineering mockup sitting on SpaceXs shopfloor.

 

[j05h]

>The seats are shown for a blunt end first entry, but at this stage they are just cartoons anyway.<br /><br />That's why I concluded that it is base-first. The seats are more like Apollo/Soyuz than CXV seats.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[soyuztma]

Spacex has posted pictures of the Dragon on their site under updates: image gallery. There are some new ones, but i'm still confused if the Dragon is supposed to make a base first reentry or nose first. <br />This picture has a flat base suggesting a nose first reentry. <br />But this picture seems to have a rounded base suggesting a base first reentry. <br />Anybody knows for sure if they are planning to make a nose first reentry or a base first reentry? <br /> <div class="Discussion_UserSignature"> </div>

 

[gunsandrockets]

Thanx for image links!<br /><br />Looking those over, I have changed my mind. I now think the capsule uses a conventional base first reentry. The base looks too much like an ablative heatshield. But most of all I can't see how the windows could survive a nose first or sideways reentry profile, it must be base first. I'm still wondering where the heck the parachutes are.<br /><br />

 

[mrcolumbus]

Reasons why that spacecraft will reenter base-first and not nose-first:<br /><br />1. Both the docking port as well as windows are in the area of heaviest reentry forces - not a good idea.<br /><br />2. nose-first reentry would require more heatshield material and due to the form a larger variety of tiles. If you cover the base (which seems to be symmetrical in shape you can use tiles that only vary slightly from each other)<br /><br />3. nose-cone first might pose problems with parashute deployment.<br /><br />

 

[docm]

Look at the pic nacnud posted of Dragon docked. It clearly shows that the cone cap is hinged, opening for docking then presumably closing again after separation. There is no reason for keeping it attached like this other than as part of a nose-first re-entry system. <br /> <div class="Discussion_UserSignature"> </div>

 

[gunsandrockets]

"Look at the pic nacnud posted of Dragon docked. It clearly shows that the cone cap is hinged, opening for docking then presumably closing again after separation. There is no reason for keeping it attached like this other than as part of a nose-first re-entry system."<br /><br />Good thinking, yet there may be a good reason after all. Recall that the Dragon is supposed to be reusable, so the nose cap might protect the docking system during reentry and landing. I've also heard a rumor that the Dragon has round folding solar panels ("mickey mouse ears") in the nose area so the nose cap would protect the solar panels as well.<br /><br />Of course that still leaves the mystery of where the parachutes are. From the x-ray illustration of the Dragon it still isn't at all clear where those chutes are. <br />

 

[crix]

Yup, pics here:<br /><br />http://www.spacex.com/press25.php<br /><br />I think this thing has got to be base first reentry. For one thing the shape and different color are to suggest its nature and also the orientation of the seats.