Speculation into what future versions of Dragon will involve

[meekGee]

So I think we're all in agreement that v1.5 and v2 are the same.

What we're not sure of is how close is it to the 1.0+SD concept that we've been seeing.

The 1.0+SD does not fit the statements of "With Dragon 1.0 we did not know what we were doing" and others.  If Dragon 2.0 is just 1.0+SD, then this is the original plan and clearly they knew exactly what they were doing.

So I'm divining that the original 1.5 got dumped, and there will be a large change.

(Version number wise, btw, Musk named the next iteration of F9 1.1, not 2.0.   Gives you an idea of his calibration of major and minor revision numbers.   Since he's calling the new Dragon 2.0, and since the term is new and coincident with talk hinting of a large change, then again - it all adds up.)

[alienmike]

I too think there is just  the current Dragon 1.0 and Dragon 2.0, which appears from Musk's statements to be a large departure from the current design. The question is, just how far will he go?

For example, it must drive him nuts that he is reusing everything except those solar cells on the trunk. He has already expended all of the fuel to take it to the space station. So would he stretch the body of Dragon vertically so that he could fit the landing legs inside the side of Dragon, and at the same time move the Solar array into dragon? How heavy are those panels and how would it impact fuel requirements for vertical landing?

I also noticed that the current configuration doesn't have the SuperDracos pointed straight down. How much does this affect the effective thrust on landing? Wouldn't stretching the body of dragon into a cylindrical shape allow a better configuration for those SuperDracos?

How would such a change affect the reentry profile? Would'nt he need at least one side to have PICAX?

I'm thinking that some of these changes are a requirement for DragonRider. Better to just rethink the whole Dragon while making such extensive changes to the configuration. Hence Elon's statement to the effect that they didn't know what they were doing on Dragon 1.0.

[ciscosdad]

Is there any clues about how much wind tunnel work they do with the Dragon?
Obviously they should be doing it for the whole launch vehicle. I wonder how well they understand the aerodynamics of the reentry vehicle, and if there is anything in the literature to guide them.
ie how far can they digress from the standard Dragon shape before they are in unknown territory?

[Mongo62]

From the transcript of Elon Musk's lecture at the Royal Aeronautical Society:

...and then there's the next generation of Dragon, the Dragon version 2, which actually does not look like that, but we'll be unveiling that fairly soon. I think that is pretty cool. Dragon version 1, we didn't really know what we were doing, most likely know more at this point. That's why Dragon version 1 looks fairly similar to things in the past, we thought, well, better not stray too far from things in the past, and hopefully it worked. Yeah, so the next version of Dragon will do that, but it looks a bit different, but it'll have legs that pop out and it has eight thrusters that are arranged in four pairs around the exterior. On the actual vehicle, the pairs are not at quite 90 degrees, partially because we wanted to shift the engines that are on the wind-ward side of the back shell, a little more towards the wind-ward side, so they're not quite 90 degrees apart, they're a little closer together on one side, and they're much bigger than what you see there.

Together with another interview done the same day:

Interviewer: And what about the man-rating of the Dragon capsule, because it has been designed from the beginning to carry, I think, seven astronauts, so in fact that's going to be happening in parallel with this new Falcon Nine then, is it?

EM: It is, yes. We've got what we call Dragon Version Two, being developed in parallel with the next generation Falcon Nine. Dragon Version Two will be capable of carrying up to seven astronauts. It will also be capable of landing propulsively, with little legs that pop out. So it will look like a real, you know, alien spaceship, I guess.

Interviewer: An actual flying saucer.

EM: Yeah, in this case, it does kind of look like... when people see the new design, I think they will be quite excited, because it really does look like something from the future.

Straight from the horse's mouth.  Make of it what you will.

[alienmike]

Thank you Mongo62. But after reading the Transcript I'm more confused than ever. Windward side of the backshell? Flying Saucer?

I hope someone here can make sense of this.

[ArbitraryConstant]

Thank you Mongo62. But after reading the Transcript I'm more confused than ever. Windward side of the backshell? Flying Saucer?

I hope someone here can make sense of this.

Taking a stab at what windward means, the center of gravity is offset to give it some lift and crossrange capability. So you're more exposed to the air flow on one side than the other.

[go4mars]

Taking a stab at what windward means, the center of gravity is offset to give it some lift and crossrange capability. So you're more exposed to the air flow on one side than the other.

Right.  So why would they want to concentrate thrusters toward the windward side?  Assuming these are deep throttling, is it for low-g force on atmospheric entry?  Some non-obvious effect related to the Martian atmosphere?  Force offset during abort to provide some sideways movement?  To make room for the fold-down landing leg/tail rudder/egress ramp or the wing-legs?   

[alienmike]

I was going to reply but go4mars already asked all of my questions 

I'm still trying to understand what it means to be more saucer shaped. Does this mean the front shell (PICAX side) has a deeper, more rounded, curvature? If so, what is the advantage? I don't see how you could make the backshell more saucer shaped.

Maybe for Christmas he'll let us get a peak.

[docmordrid]

Could he be describing an ellipsled aeroshell?

http://www.ssdl.gatech.edu/papers/mastersProjects/TheisingerJ-8900.pdf

[meekGee]

I was going to reply but go4mars already asked all of my questions 

I'm still trying to understand what it means to be more saucer shaped. Does this mean the front shell (PICAX side) has a deeper, more rounded, curvature? If so, what is the advantage? I don't see how you could make the backshell more saucer shaped.

Maybe for Christmas he'll let us get a peak.

I missed any reference to a saucer shape - are you sure it's not a half cynical comment about being a "flying saucer"?

[go4mars]

Could the "windows requirement" be part of this?

[kch]

Could the "windows requirement" be part of this?

Hadn't heard about that one -- thought they were running Linux? 

[Dave G]

Could he be describing an ellipsled aeroshell?

http://www.ssdl.gatech.edu/papers/mastersProjects/TheisingerJ-8900.pdf

If you look down from the top, F9/Dragon no longer has a circular profile.  The solar arrays on the trunk stick out a bit.  Could this have any impact on the Dragon 2 design?  Could a capsle with a non-circular base work for re-entry?

[Jim]

Some non-obvious effect related to the Martian atmosphere? 

Nothing related to that.

[corrodedNut]

So why would they want to concentrate thrusters toward the windward side?

Elon didn't say that. There's a mistake in Mongo's transcript, Elon said "away from the windward side...towards the leeward side".  The windward side is the blackened side of Dragon you see after reentry, the leeward side is the hatch/grapple door side.

[Garrett]

If you look down from the top, F9/Dragon no longer has a circular profile.  The solar arrays on the trunk stick out a bit.  Could this have any impact on the Dragon 2 design?  Could a capsle with a non-circular base work for re-entry?

Your comment implies, and made me wonder, that maybe their next version of Dragon will try to bring back the solar arrays, instead of dumping them with the trunk. Maybe they'll even try to incorporate a trunk/solar array section into the recoverable Dragon. Anybody think that's possible, or would it simply be not worth the effort at this stage in Dragon's development?

[docmordrid]

If you look down from the top, F9/Dragon no longer has a circular profile.  The solar arrays on the trunk stick out a bit.  Could this have any impact on the Dragon 2 design?  Could a capsle with a non-circular base work for re-entry?

Your comment implies, and made me wonder, that maybe their next version of Dragon will try to bring back the solar arrays, instead of dumping them with the trunk. Maybe they'll even try to incorporate a trunk/solar array section into the recoverable Dragon. Anybody think that's possible, or would it simply be not worth the effort at this stage in Dragon's development?

For sake of arguement let's say an ellipsled incorporated capsule, trunk and arrays in a single, landable unit. Would you land it on its tail or would you bring her down horizontally? If the latter ISTM all the thrusters would have to be in its "belly." If the former do you extract the crew with a ladder or platform, or do you provide an exit at the tail end?

There's a lot of ways to play with that shape.

[Elmar Moelzer]

But if the thrusters were on its belly, they could not be used for an abort, right?

[docmordrid]

That brings up Musk's "attached" comment as regards Raptor and Dragon X (since we're debating version #'s) Attached to Dragon X via the second stage, or is it by way of a  service module that can double for aborts? (getting into a lot of mass, though not necessarily if the Raptor concept comes in different sizes)

[Elmar Moelzer]

I doubt that they will want to throw away the superdracos after every launch together with the trunk. It may be that they will integrate the trunk with the main dragon capsule (since it is still quite a waste and they want reusability), but that would be a lot more complex and would mean that the dracos would need to push more mass.