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SpaceX Vehicles and Missions => SpaceX General Section => Topic started by: ciscosdad on 11/25/2012 06:31 am

Title: Speculation into what future versions of Dragon will involve
Post by: ciscosdad on 11/25/2012 06:31 am
Given the current cargo dragon is Version 1, and the crewed model is Version 2, what is known or can be inferred about the 3rd version?
Ref the Aeronautical Society lecture thread.

http://forum.nasaspaceflight.com/index.php?topic=30381.210

The info I have gleaned is:
7 crew (still)
Methane/LOX  Raptor engine Integrated
Cooler shape (whatever that means.... I speculate it looks more akin to the double clamshells of the recent Curiosity entry vehicle)
Integral cargo bay(?)  ie no trunk.

What have you gleaned for recent revelations?
Is anyone game to speculate?
All up mass? Delta V? Cargo capacity? Endurance?
Title: Re: Dragon version 3 (Speculation)
Post by: sanman on 11/25/2012 07:02 am
What is Dragon3's main mission? Is it meant for Mars, or mainly for Earth?
Title: Re: Dragon version 3 (Speculation)
Post by: mlindner on 11/25/2012 12:55 pm
Absolutely nothing is known about what dragon version 3 may or may not have or heck, if it even will exist. This topic shouldn't exist yet.
Title: Re: Dragon version 3 (Speculation)
Post by: Ben the Space Brit on 11/25/2012 05:10 pm
Purely FWIW, I understood that the next-gen design Musk was talking about was nicknamed 'Dragon-2' for ease of reference whilst the crewed Dragon is most properly termed 'Dragonrider' and could be described as 'Dragon 1.5' due to its structural and subsystem commonality with the robot cargo freighter.
Title: Re: Dragon version 3 (Speculation)
Post by: Lars_J on 11/25/2012 06:35 pm
Nope. If you combine several of the Dragon 2 quotes from Musk, the most logical interpretation is that it simply is crew Dragon. The SD thrusters and legs will account for the different appearance.

Nobody has talked about a Dragon 3. Stop inventing stuff out of nothing
Title: Re: Dragon version 3 (Speculation)
Post by: alienmike on 11/25/2012 07:09 pm
I think this thread is worthy of discussion - Musk made it sound in the video as if the next Dragon would look nothing like the current Dragon. I was surprised when I came to this forum and found only discussion on MCT/Raptor with such a major revelation. Yes, this is worthy of some speculation.

Its been bothering me for a while now. Do they actually have room for the SuperDracos and the fuel for them and for the landing legs in what looks to me to be a rather smallish form factor? Is it actually possible/a good idea, to extend the landing legs through the heat shield? My immediate thoughts were that they are looking at a completely different shape. Something that could handle much bulkier, less dense, cargo as well; including more people. And a shape that can handle all of the components necessary for a ground landing.

So I'm thinking they do a 'stretch' and give themselves more room with a more cylindrical shape and add PICAX up one of the sides like they show on the re-entry/re-usability video of the second stage.

Any thoughts on what shape you think might favor the known requirements?

(First post...)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Chris Bergin on 11/25/2012 09:33 pm
Thread renamed and trimmed.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 11/25/2012 09:37 pm
There is no Dragon 3 of course, but there is a valid question on whether the first ISS crew Dragon will be the same as the "cool looking" or "Spaceship"-y Dragon.

I think the nomenclature of calling the "cool looking"/"Spaceship"-y thing Dragon 2 and calling the first ISS crew Dragon 1.5 makes sense, and so the question is whether 1.5 exists independent of 2.0.

I'll copy my post from the general thread onto here then.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 11/25/2012 09:39 pm
EDIT:  Originally posted in the general thread

So regarding Dragons....

This is actually very obvious, and has been bugging me for a while.

SpaceX are very early to put up engineering development hardware on display (F1, F9, Dragon).

Also, once they started talking publicly about powered recovery of F9S1, Grasshopper was up in no time, and is now even flying.

They have Dragon, and they've been testing SuperDracos for quite some time now.

...  so where's Dragon 2?   There was a mockup on display, but nothing more.

I think all of this got reconciled when Elon said - "We didn't really know what we were doing with Dragon 1" and "Dragon 2 will look really cool", etc.

I think once Elon decides on a change in direction, he doesn't waste time on sunk-cost projects just because they're half-way through the engineering pipeline.

My tea-leaf reading from this is that the possibility that Dragon 2 has been greatly revised away from Dragon 1 + SuperDracos, and the conspicuously missing Dragon/Draco test-bed hopping around McGregor are in agreement here.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: mlindner on 11/25/2012 09:41 pm
There is no Dragon 3 of course, but there is a valid question on whether the first ISS crew Dragon will be the same as the "cool looking" or "Spaceship"-y Dragon.

I think the nomenclature of calling the "cool looking"/"Spaceship"-y thing Dragon 2 and calling the first ISS crew Dragon 1.5 makes sense, and so the question is whether 1.5 exists independent of 2.0.

I'll copy my post from the general thread onto here then.

Elon Musk with the recent talks has numerous times referred to Dragon 2 as the crewed dragon that will go to the ISS. There is no dragon 1.5. There is current cargo dragon (dragon 1) and crewed dragon/dragonrider (dragon 2). These are the only two versions that have been talked about.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Avron on 11/25/2012 10:00 pm
Question .. is a heart shape stable for re-entry ? vs say a cone or sphere 
Title: Re: Speculation into what future versions of Dragon will involve
Post by: ciscosdad on 11/25/2012 10:05 pm
Dragon versions:


Maybe we should agree to the version number?
Can we agree on:
Ver 1.0 is the existing Cargo dragon
Ver 1.5 is the crewed version of 1.0
Ver 2 is the "cool looking spaceship"

There is no version 3

Thanks for the rename Chris. Much more appropriate.

Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 11/25/2012 10:34 pm
Dragon versions:


Maybe we should agree to the version number?
Can we agree on:
Ver 1.0 is the existing Cargo dragon
Ver 1.5 is the crewed version of 1.0
Ver 2 is the "cool looking spaceship"

There is no version 3

Thanks for the rename Chris. Much more appropriate.

1.5 and 2 are the same
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Mongo62 on 11/25/2012 10:47 pm
I must agree with Jim here, there are only two versions of Dragon currently flying (or currently being designed):

Dragon 1 -- the current unmanned cargo transport
Dragon 2 -- the currently planned manned spacecraft

However, I also think that it is likely that Dragon 2 has undergone a thorough redesign in the past year, and no longer resembles the known mock-up.  The hints we have had from Musk indicated that the SuperDracos have been shifted from their previous 90-degree spacing, that the landing gear has been modified from the mock-up, and that it will be much more "cool looking" in appearance.  He gives as a reason for the change, that SpaceX did not really know what they were doing when designing Dragon 1, but they do now.

It will be years before Dragon 2 flies in any case.  SpaceX has the time and resources to do a complete redesign if they feel that it will result in a superior spacecraft.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 11/25/2012 10:55 pm
Can we agree on:
Ver 1.0 is the existing Cargo dragon
Ver 1.5 is the crewed version of 1.0
Ver 2 is the "cool looking spaceship"

1.5 and 2 are the same
Are version 1 and version 2 the same diameter?  Mars One suggests no.  I'm inclined to suspect dragon 2 will be larger diameter in addition to "cooler looking".
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Patchouli on 11/25/2012 10:56 pm
I must agree with Jim here, there are only two versions of Dragon currently flying (or currently being designed):

Dragon 1 -- the current unmanned cargo transport
Dragon 2 -- the currently planned manned spacecraft

However, I also think that it is likely that Dragon 2 has undergone a thorough redesign in the past year, and no longer resembles the known mock-up.  The hints we have had from Musk indicated that the SuperDracos have been shifted from their previous 90-degree spacing, that the landing gear has been modified from the mock-up, and that it will be much more "cool looking" in appearance.  He gives as a reason for the change, that SpaceX did not really know what they were doing when designing Dragon 1, but they do now.

It will be years before Dragon 2 flies in any case.  SpaceX has the time and resources to do a complete redesign if they feel that it will result in a superior spacecraft.

It's not that unusual for a spacecraft to under go a lot of changes during it's development.
Just look at the LEM and this was before it's first flight.

Things I expect to see different with Dragon 2 same basic shape but likely changes in window location ,seating arrangements, and changes to the landing gear vs the art work what has been shown.

The first crewed version may not even perform a vertical powered landing and instead would simply splash down like the cargo version.

They do have competition you know so the rev 1.0 crew vehicle most likely won't be too different from what is flying.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: billh on 11/25/2012 11:01 pm
I agree with those who have said these are all just names for the crewed Dragon they are working on for CCiCap. The outer mold line will be different because of the Super Dracos, and that is a substantial difference. I'm wondering if they might do the same thing with the landing legs. Rather than come through the heat shield (from where?) maybe they will be side mounted and extend at an angle, with some sort of aerodynamic fairing like the Super Dracos will have. Collectively that would cause the spacecraft to look quite a bit different, and be a substantial departure from a simple conical section. It is also probably more of a departure from the standard conical section than they were willing to consider for their initial design. That would be consistent, in my view, with Musk's comments about Dragon V2 in his RAeS talk.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 11/25/2012 11:37 pm
... landing legs. Rather than come through the heat shield (from where?) maybe they will be side mounted and extend at an angle, with some sort of aerodynamic fairing like the Super Dracos will have.
If the fold-down landing legs double as control surfaces, access ramps, and solar array holders, I'll have to high-5 someone somewhere. 
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 11/25/2012 11:56 pm
Can we agree on:
Ver 1.0 is the existing Cargo dragon
Ver 1.5 is the crewed version of 1.0
Ver 2 is the "cool looking spaceship"

1.5 and 2 are the same
Are version 1 and version 2 the same diameter?  Mars One suggests no.  I'm inclined to suspect dragon 2 will be larger diameter in addition to "cooler looking".

No. They will be the same diameter, there has been no indication of otherwise. "Mars One" does not count - it has little to do with reality.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: mlindner on 11/26/2012 01:38 am
Can we agree on:
Ver 1.0 is the existing Cargo dragon
Ver 1.5 is the crewed version of 1.0
Ver 2 is the "cool looking spaceship"

1.5 and 2 are the same
Are version 1 and version 2 the same diameter?  Mars One suggests no.  I'm inclined to suspect dragon 2 will be larger diameter in addition to "cooler looking".

From a friend who interned at SpaceX:
During one of Elon Musk's company employee Q&A sessions he apparently runs, someone in the room asked him about Mars One (this was soon after their announcement, including that they were using SpaceX). Elon had never heard of them. Employee explained their mission to him. Elon responded with something along the lines of "Our rockets are always waiting."

tl;dr: Mars One is not a source for any kind of imagery for SpaceX craft.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 11/26/2012 01:46 am
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.)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: alienmike on 11/26/2012 02:17 am
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.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: ciscosdad on 11/26/2012 03:11 am
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?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Mongo62 on 11/26/2012 03:27 am
From the transcript of Elon Musk's lecture (http://shitelonsays.com/transcript/elon-musk-lecture-at-the-royal-aeronautical-society-2012-11-16) at the Royal Aeronautical Society:

Quote
...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:

Quote
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.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: alienmike on 11/26/2012 04:19 am
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.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: ArbitraryConstant on 11/26/2012 04:31 am
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.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 11/26/2012 04:41 am
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?   
Title: Re: Speculation into what future versions of Dragon will involve
Post by: alienmike on 11/26/2012 04:51 am
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.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: docmordrid on 11/26/2012 04:57 am
Could he be describing an ellipsled aeroshell?

http://www.ssdl.gatech.edu/papers/mastersProjects/TheisingerJ-8900.pdf
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 11/26/2012 05:10 am
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"?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 11/26/2012 05:35 am
Could the "windows requirement" be part of this?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: kch on 11/26/2012 06:34 am
Could the "windows requirement" be part of this?

Hadn't heard about that one -- thought they were running Linux?  ;)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Dave G on 11/26/2012 09:50 am
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?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 11/26/2012 11:22 am
Some non-obvious effect related to the Martian atmosphere? 

Nothing related to that.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: corrodedNut on 11/26/2012 11:59 am
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.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Garrett on 11/26/2012 12:20 pm
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?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: docmordrid on 11/26/2012 12:56 pm
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.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 11/26/2012 01:01 pm
But if the thrusters were on its belly, they could not be used for an abort, right?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: docmordrid on 11/26/2012 01:09 pm
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)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 11/26/2012 01:15 pm
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.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: mlindner on 11/26/2012 04:37 pm
Dragon X (since we're debating version #'s)
I don't think we're debating version numbers anymore. Anyone that still was hadn't seen the latest interviews.

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.

They can't throw away the superdracos.
These are the things that _must_ come down from orbit according to the current requirements:
* Heat Shield
* SuperDracos (for propulsive landing)
* Dracos (for control)
* Capsule (of course)
* Landing Gear/Feet/etc
Optional items:
* Solar panels (I don't think these cost much, they're dirt cheap commercial silicon)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lobo on 11/26/2012 04:47 pm
I must agree with Jim here, there are only two versions of Dragon currently flying (or currently being designed):

Dragon 1 -- the current unmanned cargo transport
Dragon 2 -- the currently planned manned spacecraft

However, I also think that it is likely that Dragon 2 has undergone a thorough redesign in the past year, and no longer resembles the known mock-up.  The hints we have had from Musk indicated that the SuperDracos have been shifted from their previous 90-degree spacing, that the landing gear has been modified from the mock-up, and that it will be much more "cool looking" in appearance.  He gives as a reason for the change, that SpaceX did not really know what they were doing when designing Dragon 1, but they do now.

It will be years before Dragon 2 flies in any case.  SpaceX has the time and resources to do a complete redesign if they feel that it will result in a superior spacecraft.

This sounds like the most plausible explaination given what I've heard.  Once "Dragon 2/Dragonrider" is ready and flying, they'll replace DRagon 1 with it and just build one common spaceship that'll have a crewed and cargo version of it.  By saying "we didn't know what we were doing with DRagon 1", he probably means they thought there'd be enough room in DRagon 1 for the LAS/landing thrusters and landing gear within it's geometery, and have recently been figuring out they can't, and that's lead to a substantial redesign of the Dragon2/Dragon rider and so it'll look much different...or "cooler"...
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 11/26/2012 05:13 pm
By saying "we didn't know what we were doing with DRagon 1", he probably means they thought there'd be enough room in DRagon 1 for the LAS/landing thrusters and landing gear within it's geometery, and have recently been figuring out they can't, and that's lead to a substantial redesign of the Dragon2/Dragon rider and so it'll look much different...or "cooler"...

My advice: Don't read too much into the "different" or "cooler"... Most likely the Dragon 2 changes appearance-wise will be mostly cosmetic. It should be the same size, same pressure vessel, same heat shield. The fairings for the SD thrusters should be the major difference.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: alienmike on 11/26/2012 06:41 pm
What I'm trying to figure out is the reason for not placing the solar panels on the Dragon. Is it because of mass, or is it because of volume and configuration? For this we need some type of estimate for the mass of those panels. First, how many cells do they use?

From this photo, http://spacexlaunch.zenfolio.com/p208064181/h29AF8179#h29af8179, it appears the panels are 18x13 cells, but it looks like the first panel is a bit shorter, only 18x9. So there are 6 panels of the full sized panels and 2 shorter panels. From http://en.wikipedia.org/wiki/Solar_cell, it looks as though these are 150mm cells. That would make the panel sizes and area roughly:

18 x 13 -> 2700mm x 1950mm or 270cm x 195cm -> 52650 cm2
18 x 9   -> 2700mm x 1350mm or 270cm x 135cm -> 36450 cm2

And Total Area is about:

52650 cm2 * 6 -> 315,900 cm2
36450 cm2 * 2 ->   72,900 cm2

or 388,800 cm2 Total

From http://www.emcore.com/space-photovoltaics/space-solar-cells/, I get an estimate of 84mg/cm2, which gives 32659200 mg, or about 33 kg. It is hard to estimate how much the supporting hardware weighs, but let's say it is double the mass of the panels. That means we would be in the very rough neighborhood of 100kg.

The total down-mass capability of the Dragon is listed as 3000kg. I really don't think they would move the solar panels to the trunk for anything even close to 100kg of lost down-mass.

From this I conclude that the reason for moving the solar panels to the trunk has nothing to do with mass and everything to do with volume and configuration – the panels don't fit volume wise and would not allow for the proper placement of the thrusters.

If this is correct, it is very unlikely that the panels would be moved to the Dragon. They will need more room for the SuperDracos, not less. The only thing that might change this is a larger faring.

Any thoughts or corrections?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: mlindner on 11/26/2012 06:49 pm
The current solar arrays don't have the capability to refold. They unfold on simple torsion springs. Adding the capability to refold adds a lot of complexity to the mechanism, not to mention weight (adding motors etc) and is basically a complete redesign
Title: Re: Speculation into what future versions of Dragon will involve
Post by: alienmike on 11/26/2012 07:23 pm
The current solar arrays don't have the capability to refold. They unfold on simple torsion springs. Adding the capability to refold adds a lot of complexity to the mechanism, not to mention weight (adding motors etc) and is basically a complete redesign

I don't doubt you are correct. But if they wanted to, I'm sure they could redesign and it still would not affect the mass to such a degree that they wouldn't be able do it. My only point is, it is not mass, but volume and configuration that is preventing them from moving the panels to the Dragon.

Unless they REALLY redesign the Dragon - larger faring, this is a no go. That said, a larger faring would make the Dragon V2 look more like a flying saucer and look really cool. Is there any possibility? It would give them the extra volume they need at the base for the SuperDracos, extra fuel and landing legs. The pressure vessel could remain the same.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: mlindner on 11/26/2012 07:35 pm
The current solar arrays don't have the capability to refold. They unfold on simple torsion springs. Adding the capability to refold adds a lot of complexity to the mechanism, not to mention weight (adding motors etc) and is basically a complete redesign

Come to think of it, do any currently flying, or flown in the past spacecraft (besides ISS) have the ability to refold/retract solar panels?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 11/26/2012 07:38 pm
Guys, the trunk has more than just the solar arrays (like radiators), so you cannot get rid of it that easily.

My prediction: Dragon 2 / Crew Dragon / Dragonrider will have a trunk that is virtually identical to the current one - if not completely identical.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: alienmike on 11/26/2012 08:02 pm
Guys, the trunk has more than just the solar arrays (like radiators), so you cannot get rid of it that easily.

My prediction: Dragon 2 / Crew Dragon / Dragonrider will have a trunk that is virtually identical to the current one - if not completely identical.

Right, so we can eliminate that speculation. Truck is still there, solar arrays have not moved. How about the wider base, or elliptical base? I believe someone already mentioned that the solar arrays protrude out of the truck, so having the Dragon extend out on each side would not change much aerodynamically, right?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 11/26/2012 08:16 pm
the trunk has more than just the solar arrays (like radiators), so you cannot get rid of it that easily.
There will probably be at least 3 legs.  I would assume exactly 3.  Perhaps these fold down legs would be be multi-purpose:  Including storage for origami solar panels and heat radiators.  Other uses could be as control surfaces (2 wings and a tail rudder for when subsonic), and one of the legs could also be an egress ramp for people or rovers.  One or more of them might act as a structural window-shield during times of applied force like launch and re-entry. 

Still wondering why the engines would be concentrated, apparently to the leeward side.  Maybe for added cross-range?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 11/26/2012 08:25 pm
Guys, the trunk has more than just the solar arrays (like radiators), so you cannot get rid of it that easily.

My prediction: Dragon 2 / Crew Dragon / Dragonrider will have a trunk that is virtually identical to the current one - if not completely identical.

Right, so we can eliminate that speculation. Truck is still there, solar arrays have not moved. How about the wider base, or elliptical base? I believe someone already mentioned that the solar arrays protrude out of the truck, so having the Dragon extend out on each side would not change much aerodynamically, right?

Wait - Lars_J opinion, while he has some justification for it, is really just as speculative - there's some good justification to support the possibility of a pretty deep re-design which might extend to the trunk.  I think it's pretty open right now, until new evidence shows up.

Title: Re: Speculation into what future versions of Dragon will involve
Post by: douglas100 on 11/26/2012 10:31 pm

Come to think of it, do any currently flying, or flown in the past spacecraft (besides ISS) have the ability to refold/retract solar panels?

X-37
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lobo on 11/26/2012 10:45 pm
What I'm trying to figure out is the reason for not placing the solar panels on the Dragon. Is it because of mass, or is it because of volume and configuration? For this we need some type of estimate for the mass of those panels. First, how many cells do they use?

The total down-mass capability of the Dragon is listed as 3000kg. I really don't think they would move the solar panels to the trunk for anything even close to 100kg of lost down-mass.

From this I conclude that the reason for moving the solar panels to the trunk has nothing to do with mass and everything to do with volume and configuration – the panels don't fit volume wise and would not allow for the proper placement of the thrusters.

If this is correct, it is very unlikely that the panels would be moved to the Dragon. They will need more room for the SuperDracos, not less. The only thing that might change this is a larger faring.

Any thoughts or corrections?

This is probably one reason.

Another could be that a failure to deploy solar panels would result in a LOM.  The crew/cargo would probably have to do an emergency reentry within an orbit or two (how long to the batteries last?  A couple hours?)  In order to have them on the capsule, that means you need to have actuating doors in the skin of the capsule instead of just spring loaded pop-off covers.  Something like the grapple fixture that deploys, but more complex than that.  If there’s a snag in the hatches opening, or the arrays deploying, then it’s a LOM.  And it could be even worse if the hatches can’t be closed again, because that removes the TPS for that area in the sidewall, and could kill a crew.   I don’t believe a crewed Dragon will even have the grapple fixture because it will be actively docked, rather than captured and berthed.  So there likely won’t be anything opening or popping out of the capsule sidewalls on a crewed Dragon.
Additionally, instead of a more reliable spring loaded one-time-deploy system like they have now (I believe that’s how it currently works), they’d need some sort of more complex system of motors and guide wires (?) that can retract the arrays, and perhaps deploy them too (although they could be spring deployed, and motor retracted…but they still need a mechanism to retract them.)  Sort of like how the ISS arrays worked when they deployed and then retracted the first array, and I know they had a lot of problems retracting that array, requiring a few spacewalks and some improvised tools to finally get fully retracted.  Even if SpaceX comes up with a much more simple and reliable system for deploying and then retracting the solar panels, all it takes is a problem one time…
I would think the overall millions of dollars any Dragon mission will cost, then a few tens of thousands of dollars (or whatever it is) doesn’t seem like enough savings to warrant the risks to the mission and crews lives, most likely.   
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Dave G on 11/27/2012 07:59 am
The current solar arrays don't have the capability to refold.

Are you sure?  If I remember correctly, just before berthing, the pictures show the solar arrays refolded so they wouldn't hit anything by accident.  Then after berthing, they unfolded them again.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Silmfeanor on 11/27/2012 08:02 am
The current solar arrays don't have the capability to refold.

Are you sure?  If I remember correctly, when Dragon got near the ISS, the pictures show the solar arrays refolded so they wouldn't hit anything by accident.  Then after berthing, they unfolded them again.
not true. They where rotated, not folded.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Dave G on 11/27/2012 08:09 am
The current solar arrays don't have the capability to refold.

Are you sure?  If I remember correctly, when Dragon got near the ISS, the pictures show the solar arrays refolded so they wouldn't hit anything by accident.  Then after berthing, they unfolded them again.
not true. They where rotated, not folded.

OK, thanks for the correction.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 11/27/2012 01:42 pm
Here is a quick mockup that I made of what I believe the shape of the Dragon2 will be roughly like. the engines might be a bit further apart, making the bulges slightly wider, but I hope people get the general idea.
With the SuperDraco pods being moved closer together, I think it makes sense to combine them into a single pod on each side. That will IMHO reduce drag compared to multiple pods. If the pods were slightly wider with a larger gap between the two sets of two, there might be just enough room there for a landing leg that folds out sideways. But that space might also be needed for the maneuvering thrusters.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: robert_d on 11/27/2012 02:18 pm
My prediction is that the super dracos and landing legs will be external and mounted on pivots, attached just above the heatshield. They will be in the rearward position for launch. For reentry they will pivot forward and be partially covered with PICA-X. Once subsonic, they will pivot down again to use the super dracos to slow descent and then extend the legs. Latest SpaceX simulation shows parachutes almost all the way down. If the super dracos could be explosively separated in case of malfunction the current chutes would be able to land the capsule portion safely.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: douglas100 on 11/27/2012 03:44 pm
I think it's unlikely the SuperDracos will pivot out. It's an unnecessary complication. The nozzles are designed to take high temperatures and already get some protection from being in the stagnation zone behind the shock wave produced by the heat shield.

The landing gear will have to deploy, of course.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Dave G on 11/27/2012 03:48 pm
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.

Assuming the super-dracos will also be used for LAS, then it seems Dragon will have to land on the heat sheld end.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: solartear on 11/27/2012 03:51 pm
There will probably be at least 3 legs.  I would assume exactly 3.

Musk has said they plan to have future grasshopper have 5 legs for greater stability. I would assume the reasoning also applies to the propulsive landing Dragon. It makes sense to have 5 in case 1 leg fails, or even 2 legs if they're opposite sides.

Title: Re: Speculation into what future versions of Dragon will involve
Post by: Dave G on 11/27/2012 04:39 pm
There will probably be at least 3 legs.  I would assume exactly 3.

Musk has said they plan to have future grasshopper have 5 legs for greater stability. I would assume the reasoning also applies to the propulsive landing Dragon. It makes sense to have 5 in case 1 leg fails, or even 2 legs if they're opposite sides.



For Dragon, each leg has to somehow fit in with the heat shield, so from that perspective, the fewer legs the better.

Also remember grasshopper is really tall, skinny, and doesn't have much lateral control, so it seems appropriate that the first stage may require more legs.

In any case, the legs are primarily for preventing damage to the vehicle.  For example, if a Dragon leg breaks during landing, then I doubt anyone would be killed, so you wouldn't have loss of crew or loss of mission, and its even possible that Dragon could be refurbished. My point is you probably don't need much in terms of margins or redundancy for the legs.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: mlindner on 11/27/2012 05:27 pm
My prediction is that the super dracos and landing legs will be external and mounted on pivots, attached just above the heatshield. They will be in the rearward position for launch. For reentry they will pivot forward and be partially covered with PICA-X. Once subsonic, they will pivot down again to use the super dracos to slow descent and then extend the legs. Latest SpaceX simulation shows parachutes almost all the way down. If the super dracos could be explosively separated in case of malfunction the current chutes would be able to land the capsule portion safely.

One of the chief SpaceX design philosophies is, from what I've seen, KISS (keep it simple stupid). SuperDracos won't be deployable, and if they can make the landing legs also non-deployable then I think they will.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Norm38 on 11/27/2012 05:54 pm
***WARNING:  Electrical Engineer speculating outside his field***

What I'm considering isn't anything short term, if it would even still be called Dragon.  Listening to Musk's talks, he keeps mentioning full resuablity, and getting as close to gas-n-go operation as possible.  Having the F9 uppperstage split into second stage, capsule and trunk doesn't fit the bill.  Then there's the mention of the methane Raptor engine and the "MCT spaceship" it's attached to.

For full reusability, having a second stage that already makes orbit land separately from the capsule is a huge duplication of effort and recovery hardware mass.  Both the second stage and capsule need heat shields, RCS, legs, etc.

If the methane SC engine is sucessful as a Merlin 1D replacement for the upper stage, then can the ISP improvement from 304sec to ~380sec allow the upperstage tank and engine to be integrated with the capsule into one piece?  The empty tank makes the vehicle "fluffier" for less reentry heating, and if structural, gives mounting points for superdracos and other subsystems.

I'm picturing the MCT as a single piece, fully resuable upperstage that starts life as a LEO taxi.  But as the Dragon was designed around maybe being able to land on Mars, the MCT would be designed to be able to land on Mars and then use it's ISRU refueled Raptor engine to take off again.

Anyway, that's my MCT theory.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 11/27/2012 05:59 pm
I have wondered the same thing, Norm. One of the biggest issues I have with this is that the Superdracos would (at least IMHO) not be strong enough for a successful launch abort if the second stage and capsule were to be combined. I might be wrong though and they might just add more to the second stage (which already needs them for propulsive landing), but then how much would be left for them to gain from combining them?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: ciscosdad on 11/27/2012 10:18 pm
I like the idea of integrating the upper stage with Dragon, but the abort capability is a problem with a full methane/lox stage attached.
Maybe it could be more like the Dual Axis Lunar lander, and the dragon and Upper stage are mated and only separate in a launch abort scenario.
If the shape was more like a sled with crewed section at front and top access for cargo and solar panels and radiator on the bay doors a la shuttle. Big propellent tank and rear facing main engine.
I admit its a bit further down the track than we have been discussing, but maybe it has possibilities.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 11/27/2012 10:51 pm
But if you were to have the capsule detachable from the second stage, even if only for an abort you once again have to double many of the systems and you probably wont end up gaining much (though I may be wrong there).
Title: Re: Speculation into what future versions of Dragon will involve
Post by: ciscosdad on 11/28/2012 12:57 am
You only have to separate the crew capsule early in the launch process. At some point it becomes possible to abort with the whole upper stage (Ref Apollo abort modes.)

I would visualise the same basic arrangement as the DTAL but with aerodynamic and heat shielded hull. There may not even be any need for a shield in the separation plane (pure speculation. I am no rocket scientist as is probably obvious).
Title: Re: Speculation into what future versions of Dragon will involve
Post by: robert_d on 11/28/2012 02:56 am
But the level of complexity they are willing to accept was already shown to be substantially greater than the current version with the landing legs deploying through the heatshield. Two of Elon's comments struck me - he said the four sets of superdracos would not be exactly perpendicular to each other but oriented slightly to the "windward and leeward" sides. Also that they could develop a minimum 6 G acceleration at any point of abort. I buy the KISS argument in the sense that he does not want to change the design of the pressure vessel at this point - he and NASA are happy with the current version, and he won' give up commonality with the cargo version.  Also he said it "looks cool" For a space geek like Musk, what could be cooler than something that has moving pieces and would look like a Star Wars X-wing?


My prediction is that the super dracos and landing legs will be external and mounted on pivots...

One of the chief SpaceX design philosophies is, from what I've seen, KISS (keep it simple stupid). SuperDracos won't be deployable, and if they can make the landing legs also non-deployable then I think they will.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 11/28/2012 03:00 am
You only have to separate the crew capsule early in the launch process. At some point it becomes possible to abort with the whole upper stage (Ref Apollo abort modes.)

I would visualise the same basic arrangement as the DTAL but with aerodynamic and heat shielded hull. There may not even be any need for a shield in the separation plane (pure speculation. I am no rocket scientist as is probably obvious).

I really don't like that - it doesn't give an answer if the second stage is failing - you need to return with the capsule from an almost-orbital speed in that case.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 11/28/2012 03:39 am
A merged upper stage and Dragon will only make sense once there is a significant flight history to prove that aborts at launch are only a statistical anomaly and can be ignored.

Otherwise you are back to creating a separating cabin and/or ejection seats, and you forfeit the advantage of a merged unit anyway.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Norm38 on 11/28/2012 02:42 pm
^^^  Maybe, but abort capability at every single point doesn't really exist.  Say crewed Dragon is a reality, and a capsule is coming down for a propulsive landing.  If one of the superdraco engines were to explode, then what?  Do we double the size of Dragon to add an escape pod?  And watch payload fall to zero?

Single points of failure will always exist with any vehicle.  Personally I'd rather just have a solid vehicle with N+1 engine redundancy rather than fly in a vehicle designed to break apart into little pieces in the event one piece explodes.

Look, I understand the desire for abort modes, but I always stop before the paranoia stage.  Here in Chicagoland a father and daughter just died in a single engine plane crash.  No abort mode for them, and no one is going to start redesigning Cesnas to add ejection seats.  So why the double standard?

Subsystem redundancy?  Fine.  But airframe redundnacy?  Having each spacecraft be several completely independent spacecraft bolted together?  We don't have the mass allowance for that.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 11/28/2012 02:43 pm
I agree with Lars_J and meekGee. As attractive as merging the capsule and the upper stage is from a cost perspective, as unattractive it is from a savety perspective...
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 11/28/2012 02:45 pm
Quote
If one of the superdraco engines were to explode, then what?  Do we double the size of Dragon to add an escape pod?
I think that they have engine out capability for the dragons on propulsive landing, at least they will have parachutes as a fallback.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Norm38 on 11/28/2012 02:49 pm
^^^So have engine out capability on an integrated second stage.  If the current Dragon second stage fuel tank were to explode, aborts are probably gone anyway.  The capsule would never clear the shockwave.  Design for reliablity at the subsystem level.  But if the airframe fails, well sorry everyone dies, just like in a plane crash.

The colonization of Mars is not going to have a zero fatality rate.  Can't we accept that and do good design without the paranoia?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 11/28/2012 03:04 pm
^^^  Maybe, but abort capability at every single point doesn't really exist.  Say crewed Dragon is a reality, and a capsule is coming down for a propulsive landing.  If one of the superdraco engines were to explode, then what?  Do we double the size of Dragon to add an escape pod?  And watch payload fall to zero?

Single points of failure will always exist with any vehicle.  Personally I'd rather just have a solid vehicle with N+1 engine redundancy rather than fly in a vehicle designed to break apart into little pieces in the event one piece explodes.

Look, I understand the desire for abort modes, but I always stop before the paranoia stage.  Here in Chicagoland a father and daughter just died in a single engine plane crash.  No abort mode for them, and no one is going to start redesigning Cesnas to add ejection seats.  So why the double standard?

Subsystem redundancy?  Fine.  But airframe redundnacy?  Having each spacecraft be several completely independent spacecraft bolted together?  We don't have the mass allowance for that.

You are correct, but I think in the near term, a good assumption is that loss-of-thrust on a pump-fed engine is a likely scenario and you need to assume it will happen.  At a second level, a RUD, and loss of thrust on pressure fed engines.

IIRC, on Dragon, the SD's are paired, and they might even carry a parachute.

But yeah, people will die and we need to accept that.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 11/28/2012 03:32 pm
Quote
^^^So have engine out capability on an integrated second stage.  If the current Dragon second stage fuel tank were to explode, aborts are probably gone anyway.  The capsule would never clear the shockwave.  Design for reliablity at the subsystem level.  But if the airframe fails, well sorry everyone dies, just like in a plane crash.

Lots of assumptions there. Got data to back them up?

Quote
The colonization of Mars is not going to have a zero fatality rate.  Can't we accept that and do good design without the paranoia?
I fully agree with that notion.  If you dont like risk, dont do risky stuff like going to space and mars. Unfortunately nowadays our society has become unwilling to take risks, even to accept others taking risks.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 11/28/2012 03:39 pm
Accepting risks does not mean one has to be foolish about it.

In fact, I would argue that a robust abort scenarios allow you to take *more* risks - or at least manage them better.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Norm38 on 11/28/2012 03:43 pm
Lots of assumptions there. Got data to back them up?

This isn't my field, so no.  I would love to be proven wrong and see a simulation showing the Dragon capsule out-accelerating and surviving the explosion of the second stage tank without warning.  I just don't see it happening, and I consider that a single point of failure.

As with the super dracos.  I didn't say if an SD failed, I said exploded, as in ripped out a huge chunck of the hull.  And for sake of argument, at an altitude too low for parachutes.  Again, single point of failure.

Quote
Unfortunately nowadays our society has become unwilling to take risks, even to accept others taking risks.

That's not entirely true.  People still go mountain climbing and fly single engine planes, and no one much cares.  People are allowed to be as reckless as they want with their lives and their money.  But when government funded spaceflight fails, what happens is taxpayers say "Hey, the gov't could have wasted that money on ME instead."  Unfortunately that part is not soon likely to change.


Accepting risks does not mean one has to be foolish about it.

Where am I being foolish?  There will still be plenty of abort modes and redundancies, and still way more than offered to 747 passengers.  But a higher level of integration, and a more robust vehicle overall may be worth the loss of an abort mode that may not even really work.  Especially if it lowers costs, opens markets and increases our capabilities.

747s don't fly at 10,000ft with every passenger in a parachute ready to jump.  There are tradeoffs that have to be made sometimes.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 11/28/2012 03:59 pm
Quote
I said exploded, as in ripped out a huge chunck of the hull
Can this even happen?
We saw a first stage engine RUD during the last F9 mission and it did not result in any major damage to the stage. I would be surprised if the superdracos were not equally shielded from the rest of the craft to prevent something like that.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 11/28/2012 04:02 pm
I would be surprised if the superdracos were not equally shielded from the rest of the craft to prevent something like that.

Not needed, no rotating machinery
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 11/28/2012 04:17 pm
Quote
Not needed, no rotating machinery
Makes sense. Still only makes my original point stronger (exploding engine wont damage spacecraft).
Title: Re: Speculation into what future versions of Dragon will involve
Post by: notsorandom on 11/28/2012 04:39 pm
With talk of the Dragon 2 being radically different from Dragon 1, a staged combustion Raptor engine, and a reusable rocket this is where I think SpaceX is going. Dragon 2 may have wings, Elon has talked about airliner like operations. Landing on a runway provides the closet recovery method to that. I think that the Raptor would likely be on that spacecraft. It would make sense to bring it back on the spacecraft rather then have it separate and come back independently. The tanks are relativity cheap in comparison so they could just be jettisoned after the assent. In fact if they switch from methane to hydrogen as the fuel they can make it all the way to orbit from the ground using parallel staging. The boosters would not even have to have a great isp, just a good deal of thrust for the first minute or so of launch.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: joek on 11/28/2012 04:59 pm
With talk of the Dragon 2 being radically different from Dragon 1 ...

If by Dragon 2 you mean Dragon crew--which by all indications (including statements by Musk on several occassions) is what is being proposed for CTS--it will not be radically different than Dragon 1 (cargo).

Read the CCiCap selection statement and the SpaceX proposal.  A key theme is leveraging commonalities with, and incremental upgrades to, the existing cargo systems: Dragon, Falcon, and infrastructure.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 11/28/2012 05:00 pm
With talk of the Dragon 2 being radically different from Dragon 1, a staged combustion Raptor engine, and a reusable rocket this is where I think SpaceX is going. Dragon 2 may have wings, Elon has talked about airliner like operations.

Not. A. Chance.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Norm38 on 11/28/2012 06:11 pm
Quote
Not needed, no rotating machinery
Makes sense. Still only makes my original point stronger (exploding engine wont damage spacecraft).

Consider the entire system, I'm looking for single points of failure.  A failed SD thruster should be benign and covered by redundancy.  But if what's exploding is a ruptured hydrazine tank?  Nicked by a micrometeorite perhaps?  Does your statement still hold?

There are a whole bunch of ways a spacecraft can fail, and they can't all be covered by abort modes.  A true TSTO architecture shouldn't be ruled out just because the crew cabin can't separte, if overall reliability can be increased.  If overall reliability is judged to go down, then more work is needed.

It's like, if someone invented a true SSTO that really worked, would people demand it be made a TSTO just to add abort modes?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: hrissan on 11/28/2012 06:15 pm
With talk of the Dragon 2 being radically different from Dragon 1, a staged combustion Raptor engine, and a reusable rocket this is where I think SpaceX is going. Dragon 2 may have wings, Elon has talked about airliner like operations.

Not. A. Chance.
But Elon said "reusable", and we all know the "reusable" is an airplane with the engines burning hydrogen, fuel tank which is jetissonned and pair of side boosters. :D
Title: Re: Speculation into what future versions of Dragon will involve
Post by: notsorandom on 11/28/2012 06:34 pm
With talk of the Dragon 2 being radically different from Dragon 1, a staged combustion Raptor engine, and a reusable rocket this is where I think SpaceX is going. Dragon 2 may have wings, Elon has talked about airliner like operations.

Not. A. Chance.
But Elon said "reusable", and we all know the "reusable" is an airplane with the engines burning hydrogen, fuel tank which is jetissonned and pair of side boosters. :D
Glad someone got the joke :P
Title: Re: Speculation into what future versions of Dragon will involve
Post by: gin455res on 11/28/2012 07:51 pm
How can a dragon integrate a Raptor, surely that is much too heavy and powerful?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: StephenB on 11/28/2012 07:52 pm
So what odds would people give that Musk is switching to a biconic design for Dragon 2?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: neilh on 11/28/2012 09:50 pm
Maybe capsule flaps?

http://cse.usu.edu/foraffiliates/2007/posters_07/BMA%20Industry%20Day%202007%20v7.pdf
Title: Re: Speculation into what future versions of Dragon will involve
Post by: TaylorR137 on 11/29/2012 02:12 am
So what odds would people give that Musk is switching to a biconic design for Dragon 2?

My bet is on something like this for MCT, possibly for Dragon 2:

http://i.imgur.com/o4hLw.jpg

Concept art by Stanley Von Medvey.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Port on 11/29/2012 02:29 am
So what odds would people give that Musk is switching to a biconic design for Dragon 2?

My bet is on something like this for MCT, possibly for Dragon 2:

http://i.imgur.com/o4hLw.jpg

Concept art by Stanley Von Medvey.

Amazing concept! Guess the Solar Arrays are somewhat small though.. ;) It seems to good looking to be a actual space-vehicle (as sad as this sounds ^^)
nevertheless, i would love if the "spacecraft" atop of the new mct-rocket would somehow look a little bit like that
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 11/29/2012 02:31 am
Maybe capsule flaps?

http://cse.usu.edu/foraffiliates/2007/posters_07/BMA%20Industry%20Day%202007%20v7.pdf
Yes! 

That's pretty much exactly the concept I meant when I mentioned flip-down control surfaces that double as legs (and other things).
Title: Re: Speculation into what future versions of Dragon will involve
Post by: joek on 11/29/2012 03:10 am
My bet is on something like this for MCT, possibly for Dragon 2:

Dragon v2 will (per Musk's statements on several occasions) be available in ~3yrs.  It won't look anything like what is depicted.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: robert_d on 11/29/2012 03:23 am
It just dawned on me that the changes to dragon might be more radical than I first thought. They will not involve the integration of a raptor engine or second stage as some have proposed. But I believe Musk wants more volume to gain greater flexibility.  So I now propose that he will invert the current pressure vessel and build a t-space inspired corona style heatshield that launches as the nose of the dragon. The taper will get to an approx. 4 meter base, which will connect to a new, wider trunk that will house the solar arrays internally at launch.  The super dracos, legs and augmented environmental system would gain plenty of space,and the complete docking mechanism will extend to the back of the trunk. The new wider base will be enough to protect it during rentry.   May be total fantasy, but I should get points for thinking outside the box. :)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: joek on 11/29/2012 04:00 am
So what odds would people give that Musk is switching to a biconic design for Dragon 2?

Zero.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Dalhousie on 11/29/2012 04:33 am
So what odds would people give that Musk is switching to a biconic design for Dragon 2?

Zero.

Why do you think that?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: zodiacchris on 11/29/2012 04:46 am
So what odds would people give that Musk is switching to a biconic design for Dragon 2?

Zero.
Well, here is what elon actually said about the Dragon 2:

"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 lee-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."

So, to sum it up:
-Big SDs in pairs
-Long legs
And yes, that looks very different from the cargo version.

So, no biconic, or larger, or wing etc.

Exiting enough for me...
Title: Re: Speculation into what future versions of Dragon will involve
Post by: joek on 11/29/2012 05:26 am
So what odds would people give that Musk is switching to a biconic design for Dragon 2?
Zero.
Why do you think that?

Because "Dragon v2" is expected to be available in ~3yr based on multiple statements by Musk.  Because ~3yr is when Dragon crew needs to be available nased on the CCiCap award, and if SpaceX is to remain in the running for CTS (emphasis added)...

Quote from: CCiCap Selection Statement (pg 11)

I find SpaceX's ability to leverage its existing Dragon/Falcon cargo system with incremental targeted design upgrades reduces the overall scope of the development effort going forward.  Furthermore, their ground systems and mission control capability will be demonstrated several times on cargo missions prior to making the step to crewed missions, which is an advantage.  SpaceX also maps a series of well defined technical milesontes to specific CCiCap goals and program risks to include a clear connection between risk reduction and milesonts.  Its CTS should provide a robust operational capability with failure tolerance and dissimilar redundancy.  I recognize that there is some schedule uncertainty on the proposed Dragon/Falcon upgrades, but have good confidence that SpaceX can successfully perform the proposed effort.  Leveraging CTS off of the current cargo system offers SpaceX a strong technical advantage.  However, there is a technical weakness identified by the PEP in this area.  The PEP was concerned about the lack of sufficient detail provided to show how SpaceX will mature the integrated CTS from the current cargo configuration to a human configuration.  I share that concern, but temper the concern with the advantages of having flown the basic cargo system.  Flight experience with the cargo version will show areas of the design that need additional work.  Flying a version of the design will provide additional insight above single tests of systems.  Flying the cargo version will lower the risk to the final CTS version, if the process for changes can be identified.

Quote from: SpaceX CCiCap proposal (pg 1.1)
SpaceX has successfully demonstrated a complete integrated space transportation system. The Dragon spacecraft and Falcon 9 launch vehicle along with our ground and mission operations infrastructure form the basis of our proposed crew transportation system. The Dragon has flown to orbit on a Falcon 9 launch vehicle and safely returned to Earth on two successive missions.

In short, Dragon v2 == Dragon Crew == Dragon CTS == Dragon cargo with minimum changes.  That is the basis of SpaceX's CCiCap proposal; that is a key reason for NASA selecting SpaceX for a CCiCap award; and thus that is what SpaceX needs to deliver to meet their CCiCap commitment, minimize risk, and stay in the running for a CTS contract.

SpaceX is not going to increase risk and jeopordize their CCiCap/CTS commitments and position by haring off into some completely new Dragon configuration--nor would I expect NASA to fund or tolerate it.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 11/29/2012 05:43 am
... which is what we all thought up until Elon dropped a few comments that didn't jive with that outlook.

This is the guy that went from parachutes to propulsive landing of an entire first stage inside of a year, right?

And now is talking about "didn't know what we were doing so it looked like what everybody else was doing" and "spaceship" and "2.0" and "looks really cool" and what-not.

So something doesn't quite fit, and we need more information.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 11/29/2012 06:00 am
... which is what we all thought up until Elon dropped a few comments that didn't jive with that outlook.

This is the guy that went from parachutes to propulsive landing of an entire first stage inside of a year, right?

And now is talking about "didn't know what we were doing so it looked like what everybody else was doing" and "spaceship" and "2.0" and "looks really cool" and what-not.

So something doesn't quite fit, and we need more information.

It fits if you look at the hard data, and ignore the exaggerations by Musk.  You can't quantify what "cool" looks like to Musk, nor can you determine what he meant by them not knowing what they are doing, and now knowing what they are doing. That's just off-the-cuff fluff talk.

In short, Dragon v2 == Dragon Crew == Dragon CTS == Dragon cargo with minimum changes.  That is the basis of SpaceX's CCiCap proposal; that is a key reason for NASA selecting SpaceX for a CCiCap award; and thus that is what SpaceX needs to deliver to meet their CCiCap commitment, minimize risk, and stay in the running for a CTS contract.

SpaceX is not going to increase risk and jeopordize their CCiCap/CTS commitments and position by haring off into some completely new Dragon configuration--nor would I expect NASA to fund or tolerate it.

Exactly.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 11/29/2012 02:55 pm
... which is what we all thought up until Elon dropped a few comments that didn't jive with that outlook.

This is the guy that went from parachutes to propulsive landing of an entire first stage inside of a year, right?

And now is talking about "didn't know what we were doing so it looked like what everybody else was doing" and "spaceship" and "2.0" and "looks really cool" and what-not.

So something doesn't quite fit, and we need more information.

It fits if you look at the hard data, and ignore the exaggerations by Musk.  You can't quantify what "cool" looks like to Musk, nor can you determine what he meant by them not knowing what they are doing, and now knowing what they are doing. That's just off-the-cuff fluff talk.


If he had mentioned the specifics, there wouldn't be a doubt, now would there...

And we don't really have "hard data" that says changes were minor. 

I'd say it just about balances out

Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 11/29/2012 03:41 pm
Lars and Joek are right.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 11/29/2012 04:52 pm
Lars and Joek are right.
I didn't say they weren't - I said we're lacking data, or rather that we have weak and conflicting pseudo-data.

Do you have any other source of information here?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: king1999 on 11/29/2012 04:54 pm
Quote from: SpaceX CCiCap proposal (pg 1.1)
SpaceX has successfully demonstrated a complete integrated space transportation system. The Dragon spacecraft and Falcon 9 launch vehicle along with our ground and mission operations infrastructure form the basis of our proposed crew transportation system. The Dragon has flown to orbit on a Falcon 9 launch vehicle and safely returned to Earth on two successive missions.

In short, Dragon v2 == Dragon Crew == Dragon CTS == Dragon cargo with minimum changes.  That is the basis of SpaceX's CCiCap proposal; that is a key reason for NASA selecting SpaceX for a CCiCap award; and thus that is what SpaceX needs to deliver to meet their CCiCap commitment, minimize risk, and stay in the running for a CTS contract.

SpaceX is not going to increase risk and jeopordize their CCiCap/CTS commitments and position by haring off into some completely new Dragon configuration--nor would I expect NASA to fund or tolerate it.

Well NASA had no problem amending their contract for Falcon 9 v1.1 which has a lot of difference from v1.0.

"Falcon 9 launch vehicle along with our ground and mission operations infrastructure" will not change for the Dragon 2.0.

The shape of Dragon 2.0 may change, but many of its subsystems will stay the same. And the main reason the shape changes is to accommodate the escape/landing SD system which is a milestone of the CCiCap.

I don't see any reason NASA would not support Dragon 2.0.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 11/29/2012 05:54 pm

Well NASA had no problem amending their contract for Falcon 9 v1.1 which has a lot of difference from v1.0.


Meaningless, the contract isn't for a launch vehicle.  And also, it didn't really change, only tank lengths and upgraded engine with a different pattern.  Anyways, V1.0 vs V1.1 is minor compared to Atlas vs Delta with CST-100
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lobo on 11/29/2012 06:56 pm
I wonder if DRagon 2 might incorporate ECLSS for long duration independant operation, or at least incorporate the capacity for long duration ECLSS to be developed and added to it after such a time as it might be servicing the ISS. 

And Perahps designed to accept a future service module for BLEO missions?

I don't think it's too unreasonable to think Elon might be interested in sending people around the moon, or to L points.  Might raise some interesting press if Elon were to send a crew around the moon before NASA did on FH.  A FH stack is no taller than a F9 v1.1 stack, so if SpaceX modifies their LC-40 to launch crews to the ISS on Dragon 2, it should be able to also service crews on a DRagon2/FH stack. 
I'd think a FH should be able to throw around 20mt through TLI?  That should be enough for Dragon 2 with a BLEO service module attached.
A super draco would probably make a good SMME as it can deeply throttle. 
If mass is tight, they might get creative and design the LAS/Landing propellant to be able to be used to fuel the SMME for LOI and TEI burns in the case of a successful launch where the LAS system is not needed.  And then the capsule could do a water landing instead of a ground landing.  That way they don't have to put the LAS/landing propellant and the SMME propellant both through TLI, and could save a few tonnes if the propellant could be shared. 

But I digress...just wondering if DRagon 2 might actually be designed with allowances for a BLEO version.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Dalhousie on 11/29/2012 08:16 pm
Thanks joek & zodiacchris for the comments on biconics.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: joek on 11/30/2012 03:05 am
Well NASA had no problem amending their contract for Falcon 9 v1.1 which has a lot of difference from v1.0.

What Jim said.  Also, what makes you think the contract required amendment for Falcon 9 v1.1?  The only stipulation in the CRS contract is (note absence of detail as to launch vehicle and spacecraft configuration)...
Quote from: SpaceX CRS contract (pg 57)
IV.A.1 MINIMUM REQUIREMENTS COMPLIANCE
Second, SpaceX will rely upon space vehicles manufactured in the United States in accordance with U.S. Space Transportation Policy... Specifically, SpaceX will rely upon its Falcon 9 launch vehicle and Dragon spacecraft, both of which are manufactured by SpaceX at facilities in the United States and use minimal foreign components or technologies in a manner consistent with U.S. laws and regulations.

Quote
I don't see any reason NASA would not support Dragon 2.0.

NASA has demonstrably supported development of the next version of Dragon, aka "Dragon 2"; specifically, Dragon Crew as proposed and represented by SpaceX for CCiCap and presumably CTS.  However, that does not mean NASA is going to support development of a solution that signifantly increase CCiCap/CTS program risk as suggested in some previous posts.

There's a contract (SAA) based on specific stipulations and representations by SpaceX and expectations by NASA, and a potentially lucerative contract (CTS) hanging in the balance.  That constrains Musk's options for Dragon v2.  Contrast that with a lot of speculation based on a few open-to-interpretation statements by Musk, and unwarranted assumptions about SpaceX's freedom to maneuver--assuming SpaceX still intends to meet their CCiCap commitments and win a CTS contract.

Dragon v3...v47?  Maybe... biconic, wings, flying saucer,... whatever. Feel free to speculate.  However, that speculation belongs in the same category as MCT, not Dragon v2.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: pathfinder_01 on 11/30/2012 03:56 am
I wonder if DRagon 2 might incorporate ECLSS for long duration independant operation, or at least incorporate the capacity for long duration ECLSS to be developed and added to it after such a time as it might be servicing the ISS. 



Given that Apollo technology could support 3 people in a smaller capsule for 14 days and was latter used in early shuttle missions I don't think long duration independant operation will be a problem.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: CuddlyRocket on 11/30/2012 07:22 am
There's a contract (SAA) based on specific stipulations and representations by SpaceX and expectations by NASA, and a potentially lucerative contract (CTS) hanging in the balance.  That constrains Musk's options for Dragon v2.  Contrast that with a lot of speculation based on a few open-to-interpretation statements by Musk, and unwarranted assumptions about SpaceX's freedom to maneuver--assuming SpaceX still intends to meet their CCiCap commitments and win a CTS contract.

Unless of course SpaceX has already cleared any design change with NASA. And that depends on how significant NASA thinks any changes are. Basically, all that seems to be changed is the shape of the capsule; everything else is either the same (pad, launcher, trunk, avionics) or has still to be designed/developed/tested in any event. If NASA has taken the change from F9 1.0 to 1.1 and Merlin 1C to 1D (and possibly to Raptor) in stride, why would they have kittens over a change in capsule shape (especially if it's to a shape that NASA has already tested and verified)?

And there is still the possibility of testing the new shape in a cargo version multiiple times before the first manned flight.

Still, I don't think we can read too much into Elon's 'flying saucer' comment. He probably means 'UFO' and there are lots of alleged shapes for UFOs. I think it's better to think of what design objective might warrant a change in capsule shape. The one I can think of is to reduce the angle the sides of the capsule make with the vertical. This would increase internal volume, giving more room for equipment (assuming you're not increasing the number of crew) and make it easier to reduce cosine losses on the SuperDracos.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 11/30/2012 10:54 am
If NASA has taken the change from F9 1.0 to 1.1 and Merlin 1C to 1D (and possibly to Raptor) in stride, why would they have kittens over a change in capsule shape (especially if it's to a shape that NASA has already tested and verified)?

Because

a.  Raptor is not flying near term for crew

b.  NASA is basically launch vehicle agnostic.  It isn't the primary crew (or cargo) interface.

c.  The changes from V1 to V1.1 are minor and will have more flight time than V1.0
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 11/30/2012 10:56 am
The one I can think of is to reduce the angle the sides of the capsule make with the vertical. This would increase internal volume, giving more room for equipment (assuming you're not increasing the number of crew) and make it easier to reduce cosine losses on the SuperDracos.

No, it is already shallow.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 11/30/2012 11:16 am
I don't think we can read too much into Elon's 'flying saucer' comment. He probably means 'UFO' and there are lots of alleged shapes for UFOs.
I believe the quote was that it will look "like something from the future."

Unless there's another interview I'm not aware of, Elon never said flying saucer.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: CuddlyRocket on 12/01/2012 09:13 am
Unless there's another interview I'm not aware of, Elon never said flying saucer.

You're very probably right - another good reason for not reading too much into it! :)

Because

a.  Raptor is not flying near term for crew

b.  NASA is basically launch vehicle agnostic.  It isn't the primary crew (or cargo) interface.

c.  The changes from V1 to V1.1 are minor and will have more flight time than V1.0

OK, but they are changing engines from Merlin 1C to 1D. And given everything that needs to be developed and tested etc it's the capsule shape that's going to be a step too far for NASA? Given that it has to be test-flown in any event, and the new shape may even be used for cargo Dragons beforehand with more missions than the present version.

Ultimately, Elon is no fool and he wouldn't risk his contract by changing to a new shape without taking soundings from the relevant people at NASA as to their attitude.

No, it is already shallow.

It's not as shallow as it could be.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 12/01/2012 11:21 am

It's not as shallow as it could be.

Unsubstantiated
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 12/01/2012 11:26 am
Because

a.  Raptor is not flying near term for crew

b.  NASA is basically launch vehicle agnostic.  It isn't the primary crew (or cargo) interface.

c.  The changes from V1 to V1.1 are minor and will have more flight time than V1.0

OK, but they are changing engines from Merlin 1C to 1D. And given everything that needs to be developed and tested etc it's the capsule shape that's going to be a step too far for NASA? Given that it has to be test-flown in any event, and the new shape may even be used for cargo Dragons beforehand with more missions than the present version.

Ultimately, Elon is no fool and he wouldn't risk his contract by changing to a new shape without taking soundings from the relevant people at NASA as to their attitude.


So what?  It is basically the same engine.
It isn't just the capsule shape, but capsule shape is not the equivalent to the engine change, or stage length change.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 12/01/2012 09:15 pm
No, it is already shallow.

It's not as shallow as it could be.

If the sidewall is any steeper, it will experience much more severe heating - Dragon re-enters at a ~15 degree for a lifting reentry. (see image below) Note how the "back side" is virtually parallel to air flow - this is the side that chars the most.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 12/01/2012 10:44 pm
I agree with Lars there. Certainly a good point.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: sanman on 12/08/2012 01:14 pm
Does anyone know of any sketches/photos/renderings of what this Dragon 2.0 is supposed to look like? When you say "cool looking" - in what way? What does it look like? I tried Googling, but couldn't find anything.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 12/08/2012 02:04 pm
Quote
Does anyone know of any sketches/photos/renderings of what this Dragon 2.0 is supposed to look like? When you say "cool looking" - in what way? What does it look like? I tried Googling, but couldn't find anything.
No, IIRC Musk wanted to keep it under wraps until some time next year, but I might be remembering this wrong.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: douglas100 on 12/08/2012 10:38 pm
I agree with Lars there. Certainly a good point.

Yes indeed. Soyuz has a steeper sidewall and this is what the most recent one looked like after landing: http://spaceflight.nasa.gov/gallery/images/station/crew-33/hires/201211190015hq.jpg (http://spaceflight.nasa.gov/gallery/images/station/crew-33/hires/201211190015hq.jpg)

SpaceX were trading interior volume versus sidewall angle when they designed Dragon. My amateur guess is that they will essentially keep the same mold line for the new version.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: CuddlyRocket on 12/09/2012 11:02 am
But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

I assume that any change of shape wouldn't be for aesthetic reasons but for engineering ones. The only drivers I can think of are to increase the internal volume; reduce mass for a given volume; reduce the cost of manufacture or to improve the effectiveness of the SuperDracos by reducing the cosine losses. Are there any others?

Noting Lars_J's point about the re-entry angle etc, would it be possible for the capsule to be asymmetric with the 'front side' sidewall at a steeper angle? Can an asymmetric shape nonetheless have symmetric aerodynamic loads? Could the fact that the SuperDracos are not at 90 degrees have anything to do with this?

I note that the Orion is planned to have almost twice the internal pressurised volume as the current Dragon. Elon might want to close the gap if possible; somewhat at least. Another way to increase volume would to make the diameter of the base wider (though this doesn't change the shape). Although the F91.1 and FH have the same diameter as the F1.0, the trunk could be flared to match the two (the current design of the Orion SM seems to do something similar). Payload fairing often have greater diameters than their launchers, so this wouldn't seem to present any particular problems?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: douglas100 on 12/09/2012 01:30 pm

But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Having the SuperDracos mounted in the sidewalls will certainly make it look different. They may be mounted in pods which protrude further than the version we've seen already. So in that sense, the mold line would be a bit different. To redesign the basic shape would be close to developing a completely new vehicle and I think it would be too costly. I very much doubt the basic shape of the new vehicle will be asymmetrical.

As far as Musk's remarks are concerned, What he means by "cool" and "futuristic" in this context is anyone's guess. That's for the Kremlinologists.  :)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 12/09/2012 02:04 pm
Especially in light of the requirement for reusability, I think the major driver is reducing of the cosine losses on the SDs, which would mean, at a minimum, sticking them out further.

As for changing the vessel shape, I don't see the clear driver for it, but I also don't see why that's so difficult. Seems like development wise, the vessel never was the most difficult item - this goes back to vertical integration - SpaceX's idea of "small changes" is quite different than that of other companies...

Just from what we know, the SD pods are already changing the external shape so that CFD work has to be re-done.  Load paths are affected by the SDs of course. Placement of components around the vehicle - same.  Life support etc - new.  Docking mechanism - new.   So really, why does changing the pressure vessel shape suddenly takes us to a "new level of change"? 
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Hooperball on 12/09/2012 05:33 pm
@CuddlyRocket,

Another driver is landing legs.

From a weight saving stand point it seems logical that these legs would be integral with super draco structural mounts.

From a simplicity stand point, IF the super dracos are housed in pods to improve cosine losses, legs that are fixed to or deployable from these pods would save the hassle of having to pierce the heat shield with legs to land.

S
Title: Re: Speculation into what future versions of Dragon will involve
Post by: IRobot on 12/09/2012 05:42 pm
A "perfect" capsule would have a larger top, to reduce cosine losses for the super dracos, to increase volume and to include landing gear, but that would require some kind of inflatable shield, but those are not yet proven tech...
Title: Re: Speculation into what future versions of Dragon will involve
Post by: cambrianera on 12/09/2012 07:12 pm
A question to the people that believes that Dragon 2.0 will be similar to cargo Dragon: where is SpaceX going to fit SuperDracos?
Some models seen on displays or in artworks seems incompatible with dragon pressure vessel.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 12/09/2012 09:09 pm
A question to the people that believes that Dragon 2.0 will be similar to cargo Dragon: where is SpaceX going to fit SuperDracos?
Some models seen on displays or in artworks seems incompatible with dragon pressure vessel.

No, look closer, it is compatible. (both that display model and the rendering you attached are at least) Notice the raised areas around the thrusters. The SD's would be mounted on the outside of the pressure vessel, and the raised area/fairing would protect them during ascent.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 12/09/2012 09:17 pm
But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Oh c'mon. "futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think:  http://en.wikipedia.org/wiki/Occam's_razor
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jason1701 on 12/09/2012 09:33 pm
A question to the people that believes that Dragon 2.0 will be similar to cargo Dragon: where is SpaceX going to fit SuperDracos?
Some models seen on displays or in artworks seems incompatible with dragon pressure vessel.

No, look closer, it is compatible. (both that display model and the rendering you attached are at least) Notice the raised areas around the thrusters. The SD's would be mounted on the outside of the pressure vessel, and the raised area/fairing would protect them during ascent.

The basic concept is compatible, but I think (and believe Elon has been implying) that the fairings will need to be much bigger.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 12/09/2012 10:28 pm
But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Oh c'mon. "futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think:  http://en.wikipedia.org/wiki/Occam's_razor

Lars, Occam's razor says that a simpler explanation to a given observation is *most likely* to be correct.

We don't have an observation, and we don't have competing explanations...

We are guessing how many changes will be in Dragon 2.0 vs Dragon 1.0.

Given all that IS changing, I am not sure that a new pressure vessel is such a big deal (why would it be?).  I do agree that it is not at the top of the priority list for them, but we'll have to wait till we have more info.

Until more information is available, this thread is going to be re-hashing arguments....
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Elmar Moelzer on 12/09/2012 11:03 pm
Well from what I understand Elon said that the SDs will move away from the "bottom side" of the capsile. That could still mean two symetry axis (as in a sketch I posted earlier). It could also mean that it will only have one symetry axis with two pairs of superdracos firing at a really odd angle.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: beancounter on 12/10/2012 12:36 am
But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Oh c'mon. "futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think:  http://en.wikipedia.org/wiki/Occam's_razor

Lars, Occam's razor says that a simpler explanation to a given observation is *most likely* to be correct.

We don't have an observation, and we don't have competing explanations...

We are guessing how many changes will be in Dragon 2.0 vs Dragon 1.0.

Given all that IS changing, I am not sure that a new pressure vessel is such a big deal (why would it be?).  I do agree that it is not at the top of the priority list for them, but we'll have to wait till we have more info.

Until more information is available, this thread is going to be re-hashing arguments....

Is Dragon2 really what Elon is talking about?  Is it Dragon for crew under CiCap or is it something further out say for Mars or BEO?  I don't know but it's fun reading what others think.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 12/10/2012 01:20 am
But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Oh c'mon. "futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think:  http://en.wikipedia.org/wiki/Occam's_razor

Lars, Occam's razor says that a simpler explanation to a given observation is *most likely* to be correct.

We don't have an observation, and we don't have competing explanations...

Yes we do. If you haven't seen it, you should read the thread again.
- Option A: Dragon 2 is simply CCICAP crew Dragon, minimal changes - Musk is exaggerating.
- Option B: Dragon 2 is completely different, all kinds of futuristic, looks very different than the current Dragon. It could be bigger, a completely different shape.

Hmmmm... Which one is more likely. ::8
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 12/10/2012 01:58 am
But Elon is quite clear that the Dragon 2 will look different; more futuristic. Could just be spin, but if it does look different it's difficult to see how if they keep the same mold line etc.

Oh c'mon. "futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think:  http://en.wikipedia.org/wiki/Occam's_razor

Lars, Occam's razor says that a simpler explanation to a given observation is *most likely* to be correct.

We don't have an observation, and we don't have competing explanations...

Yes we do. If you haven't seen it, you should read the thread again.
- Option A: Dragon 2 is simply CCICAP crew Dragon, minimal changes - Musk is exaggerating.
- Option B: Dragon 2 is completely different, all kinds of futuristic, looks very different than the current Dragon. It could be bigger, a completely different shape.

Hmmmm... Which one is more likely. ::8


Those are not too explanations of some observation...   Those are speculations trying to interpret what Elon might have meant and guess what he might have hidden in his garage...  They don't explain anything.

Anyway, semantics aside - nobody answered why changing the pressure vessel is such a big deal.

Everyone agrees that the outer mold line is new because the SDs are now sticking out a lot, thus re-entry dynamics are new, obviously the SD systems (LAS, landing) are new, the regular Draco motors probably moved to accommodate the SDs and maybe there are fewer of them, there's new life support systems, new docking mechanism. 

At this point - what exactly do you mean by "small change" ?    I actually don't see how keeping it unchanged saves much.

Once we realize the cargo Dragon can't "just have SD attached to it", then it's a new vehicle.  They didn't call it v1.1 or v1.5.  They called it 2.0, and I think this means that went back and designed it from scratch.  And that effort could have started a lot earlier than you think, even before the first Dragon flew.   You learn a lot by building an iteration of hardware even before you actually test it out.

To me, btw, a "large change" would be if some of the launch delta-V would be moved to the Dragon.  Now that there's major thrust capability to it, I don't see why SII won't cut out 1 km/sec early.  (I wonder where it will reenter if they do that...)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: ArbitraryConstant on 12/10/2012 04:15 am
Now that there's major thrust capability to it, I don't see why SII won't cut out 1 km/sec early.  (I wonder where it will reenter if they do that...)
Because the SpaceX abort system uses propellant needed for orbital maneuvering and the only reason that's a win is because if you abort you're about to parachute into the ocean and don't need the propellant. If you need bigtime delta-v, you're better off using a pump fed engine with higher ISP propellants, no cosine losses, and a proper vac nozzle. Exactly the second stage they already have, in other words.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 12/10/2012 04:54 am
They didn't call it v1.1 or v1.5.  They called it 2.0, and I think this means that went back and designed it from scratch.

Sigh... In other words, you ignore what evidence is out there (CCiCap, statements by informed people like Jim) and decide to make stuff up. Well, prepare to be disappointed.

And BTW, since you seem to care so much about determining meaning in numerology - I believe Musk called in "Dragon 2", not "Dragon 2.0". There is a fine difference there, if you care to see it.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: CuddlyRocket on 12/10/2012 05:07 am
..."futuristic". "different". Words that are used when one does not wish to provide specifics, because it could mean literally *ANYTHING*. Occam's razor applies here, I think...

But the simplest explanation of what Elon means when he says the Dragon 2 will look different to the existing Dragon and 'futuristic' is that it will look different to and futuristic etc. Any other explanation gets you into conspiracy theories about why Elon is saying something not true.

It might be a correct conspiracy theory of course :), as real life often doesn't follow Occam's Razor, but I'm not seeking to divine truth and falsehood here. All I'm asking and considering is if the Dragon 2 looks different etc, how and why might that be true. This is a discussion board after all, not an arbitration service! The truth will out in due course - no later than the test of the LAS, and probably earlier.

I think the point is well made that given all the other changes necessitated by the incorporation of SuperDracos and landing legs etc, that a fundamental redesign might not introduce that much more time and expense. Also, there may well be problems with the Dragon and/or its manufacture that SpaceX has not divulged but which it might want to correct.

One other possible driver for a change is Elon's comment that the Dragon 2 could be used to land on any other Solar System body with a solid or liquid surface. Any there any changes that might make it more effective for such purposes; that might make it a more effective deployer of scientific instrument packages or even act as a launch pad for a sample return, for instance?

Of course the priority for the design is to come up with a safe, effective and cost efficient LEO/ISS crew vehicle!
Title: Re: Speculation into what future versions of Dragon will involve
Post by: beancounter on 12/10/2012 05:17 am
No the simplest explanation is that Elon's been reading NS forum and has simply decided to throw something out there to see what we all think :)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 12/10/2012 06:01 am
They didn't call it v1.1 or v1.5.  They called it 2.0, and I think this means that went back and designed it from scratch.

Sigh... In other words, you ignore what evidence is out there (CCiCap, statements by informed people like Jim) and decide to make stuff up. Well, prepare to be disappointed.

And BTW, since you seem to care so much about determining meaning in numerology - I believe Musk called in "Dragon 2", not "Dragon 2.0". There is a fine difference there, if you care to see it.

Seriously - the version # is the least important bit in that post... 

And what evidence are you talking about that I'm supposedly ignoring? That the pressure vessel hasn't changed?  I'd love to hear about any such evidence, one way or the other, since just like the rest of us here, I don't know....

But how about the rest of my list of changes - did anyone show evidence in this entire thread to the contrary?  Can you even argue that they won't be there?

How's about you answer the original question - why is changing the pressure vessel so much more significant than all those other changes?

Title: Re: Speculation into what future versions of Dragon will involve
Post by: beancounter on 12/10/2012 06:24 am
They didn't call it v1.1 or v1.5.  They called it 2.0, and I think this means that went back and designed it from scratch.

Sigh... In other words, you ignore what evidence is out there (CCiCap, statements by informed people like Jim) and decide to make stuff up. Well, prepare to be disappointed.

And BTW, since you seem to care so much about determining meaning in numerology - I believe Musk called in "Dragon 2", not "Dragon 2.0". There is a fine difference there, if you care to see it.

Seriously - the version # is the least important bit in that post... 

And what evidence are you talking about that I'm supposedly ignoring? That the pressure vessel hasn't changed?  I'd love to hear about any such evidence, one way or the other, since just like the rest of us here, I don't know....

But how about the rest of my list of changes - did anyone show evidence in this entire thread to the contrary?  Can you even argue that they won't be there?

How's about you answer the original question - why is changing the pressure vessel so much more significant than all those other changes?



I'll go with Option B above and prepare to be disappointed.  :)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: cambrianera on 12/10/2012 07:10 am
A question to the people that believes that Dragon 2.0 will be similar to cargo Dragon: where is SpaceX going to fit SuperDracos?
Some models seen on displays or in artworks seems incompatible with dragon pressure vessel.

No, look closer, it is compatible. (both that display model and the rendering you attached are at least) Notice the raised areas around the thrusters. The SD's would be mounted on the outside of the pressure vessel, and the raised area/fairing would protect them during ascent.
If you are convinced, good.
Personally I see the attached model as some old jokes about big tv set disguised as flat tv, with the big hole in the wall and the next room half occupied by the tv set; in a house this is fun, in a pressure vessel...
Also, I cannot see the load path on the thin walls, anyway I hope "we'll be unveiling that fairly soon" (Elon's words).
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 12/10/2012 07:38 am
They didn't call it v1.1 or v1.5.  They called it 2.0, and I think this means that went back and designed it from scratch.

Sigh... In other words, you ignore what evidence is out there (CCiCap, statements by informed people like Jim) and decide to make stuff up. Well, prepare to be disappointed.

And BTW, since you seem to care so much about determining meaning in numerology - I believe Musk called in "Dragon 2", not "Dragon 2.0". There is a fine difference there, if you care to see it.

Seriously - the version # is the least important bit in that post...

Yet it is your (apparently) entire basis for thinking that it is designed from scratch. 

Quote
And what evidence are you talking about that I'm supposedly ignoring? That the pressure vessel hasn't changed?  I'd love to hear about any such evidence, one way or the other, since just like the rest of us here, I don't know....

Who has claimed that the pressure vessel won't change at all? (It is demonstrably false, since the top of it will connect the docking collar instead of the berthing one) But you are making the claims about significant revisions. Back them up.

Quote
But how about the rest of my list of changes - did anyone show evidence in this entire thread to the contrary?  Can you even argue that they won't be there?

I think Dragon 2 will have wings without any evidence. Can you disprove it?  ::)
I think Dragon 2 will have a warp drive without any evidence. Can you disprove it? ::)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: A_M_Swallow on 12/10/2012 07:44 am
{snip}
I think Dragon 2 will have a warp drive without any evidence. Can you disprove it? ::)

Yes.  No warp drive has yet reached TRL 2.   :o  :P
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 12/10/2012 02:06 pm
Yet it is your (apparently) entire basis for thinking that it is designed from scratch. 
No, it is the list of changes I put up that made me call it "from scratch".

I'm still btw looking forward to any evidence to support your opinion. Me, I have none.  And, what wings?  I never said wings.

Tell me - which of these changes do you think *won't* happen:
(I don't think all of them will, just looking for your opinion)

- Super Dracos
- LAS control for SDs
- Landing control for SDs
- Structural changes to capsule to support SDs
- SDs that protrude outwards beyond what we've seen so far
- Larger propellant tanks
- Repositioning of thrusters on capsule wall, propellant line re-routing
- Landing gear anchored on periphery, not through heat shield as shown
- Docking mechanism
- Landing gear
- Outer mold line
- Aerodynamic flow during re-entry because of SDs
- Life support system
- Power system to support life support system
- Internal design for crew
- Shape of internal vessel

Then, tell me what you think will actually stay the same.

This way we won't have to argue about the semantics of "small" vs. "large" changes.

Title: Re: Speculation into what future versions of Dragon will involve
Post by: cambrianera on 12/16/2012 01:11 pm
Found another picture of "Naked Dragon".
Seriously, I can't see enough space to fit 8 SuperDracos, except for having very big external bulges, with lot of implications on airflow and load path.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: joek on 12/16/2012 10:27 pm
In addition to the other references previously posted, you might want to look at this presentation (http://www.nal-jsc.org/Presentation_NASA%20Alumni%20League_JSC__Bowersox_%20Final_012511%20(2).pdf), in particular slides 18, 19 and 29.
Quote from: SpaceX
- Both Dragon & Falcon 9 were designed from inception to readily accommodate crew
- Existing Dragon systems designed to accommodate escape system, including abort loads
- Thermal Control System & radiator are sized for crew requirements
- >210 days orbital life span: Positive energy balance...

There doesn't appear to be anything to suggest "from scratch"; everything SpaceX has said strongly suggests otherwise.

edit: In short, based on SpaceX's statements; from your list...
No substantive changes:
- Structural changes to capsule to support SDs
- Larger propellant tanks
- Power system to support life support system
- Shape of internal vessel
Expected/nominal changes:
- Docking mechanism
- Life support system (per SpaceX "up-rated... add CO2 & Humidity control")
- Internal design for crew (per SpaceX "Seats, displays and controls")
Title: Re: Speculation into what future versions of Dragon will involve
Post by: beancounter on 12/17/2012 12:59 am
Found another picture of "Naked Dragon".
Seriously, I can't see enough space to fit 8 SuperDracos, except for having very big external bulges, with lot of implications on airflow and load path.


Yes I'd agree with the SD assessment unless there's a lot of extraneous equipment being used in the SD test version.  Looked a pictures of the Merlins.  Never seemed to be much difference between test and final engines though.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 12/17/2012 02:51 am
In addition to the other references previously posted, you might want to look at this presentation (http://www.nal-jsc.org/Presentation_NASA%20Alumni%20League_JSC__Bowersox_%20Final_012511%20(2).pdf), in particular slides 18, 19 and 29.
Quote from: SpaceX
- Both Dragon & Falcon 9 were designed from inception to readily accommodate crew
- Existing Dragon systems designed to accommodate escape system, including abort loads
- Thermal Control System & radiator are sized for crew requirements
- >210 days orbital life span: Positive energy balance...

There doesn't appear to be anything to suggest "from scratch"; everything SpaceX has said strongly suggests otherwise.

edit: In short, based on SpaceX's statements; from your list...
No substantive changes:
- Structural changes to capsule to support SDs
- Larger propellant tanks
- Power system to support life support system
- Shape of internal vessel
Expected/nominal changes:
- Docking mechanism
- Life support system (per SpaceX "up-rated... add CO2 & Humidity control")
- Internal design for crew (per SpaceX "Seats, displays and controls")


Are you saying the current propellant tanks for the Dracos are already large enough for landing and LAS?

And that you can see where the SD's fit and attach?

I agree with you about the power system maybe being large enough already.

As always, my take about what SpaceX says is that it often reflects what's on the drawing boards, not what is currently flying. Case in point - engine out capability on F9, as articulated by Elon, matches what the Merlin 1D can do, but at the time he said it only the 1C existed as far as we knew.

Either way - most of the list still stands even if one or two of the bullets is already in the Dragon 1.0
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jason1701 on 12/17/2012 04:05 am
In addition to the other references previously posted, you might want to look at this presentation (http://www.nal-jsc.org/Presentation_NASA%20Alumni%20League_JSC__Bowersox_%20Final_012511%20(2).pdf), in particular slides 18, 19 and 29.
Quote from: SpaceX
- Both Dragon & Falcon 9 were designed from inception to readily accommodate crew
- Existing Dragon systems designed to accommodate escape system, including abort loads
- Thermal Control System & radiator are sized for crew requirements
- >210 days orbital life span: Positive energy balance...

There doesn't appear to be anything to suggest "from scratch"; everything SpaceX has said strongly suggests otherwise.

edit: In short, based on SpaceX's statements; from your list...
No substantive changes:
- Structural changes to capsule to support SDs
- Larger propellant tanks
- Power system to support life support system
- Shape of internal vessel
Expected/nominal changes:
- Docking mechanism
- Life support system (per SpaceX "up-rated... add CO2 & Humidity control")
- Internal design for crew (per SpaceX "Seats, displays and controls")


Are you saying the current propellant tanks for the Dracos are already large enough for landing and LAS?

And that you can see where the SD's fit and attach?

I agree with you about the power system maybe being large enough already.

As always, my take about what SpaceX says is that it often reflects what's on the drawing boards, not what is currently flying. Case in point - engine out capability on F9, as articulated by Elon, matches what the Merlin 1D can do, but at the time he said it only the 1C existed as far as we knew.

Either way - most of the list still stands even if one or two of the bullets is already in the Dragon 1.0

Dragon is thought to have about 500 m/s delta-v, which should be more than enough for either a launch abort or a thruster-assisted touchdown after a mission. A purely propulsive touchdown might be more than that can handle.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 12/17/2012 04:41 am
500 is not bad.  Didn't realize it was that much.
Is that including cosine errors when firing "downwards"?
Hopefully with the SD's sticking out, that effect will go away - cosine effects are forgiving over the first 15-20 degrees.

How much is used for de-orbiting?

500 is definitely enough for LAS (enough for 10g for 5 seconds, if anyone can take it)

For landing, in principle, you only need as much as your terminal velocity, which for a largely empty aluminum can will be (IIANM) some 100 m/s. Cynically speaking, the rest will only make it easier for S&R to find the capsule if the landing went badly. 

OK - so if the stored impulse is already 500 m/s, I'm taking the "larger fuel tanks" out of the list.

The structural attach points themselves are not a big deal either - they're a straight forward change, not the biggest item on that list.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: cambrianera on 12/17/2012 01:12 pm
Looking at some old posts in "SpaceX:Advanced Launch Abort System(LAS)" I tried to get speculative dimensions of the SD.
Diameter about 200 mm (8"), lenght about 500 mm (20").
Pipes are about 40 mm (1 1/2").
See:
http://forum.nasaspaceflight.com/index.php?topic=24979.msg918360#msg918360
http://forum.nasaspaceflight.com/index.php?topic=24979.msg918361#msg918361
http://forum.nasaspaceflight.com/index.php?topic=24979.msg918470#msg918470
Not impossible, but quite tight to install.

Can't see where they fit into the displayed model's and artwork's bulges.
http://forum.nasaspaceflight.com/index.php?topic=30455.msg989774#msg989774
Considering also a pair of them has 130000 N of thrust, I can't see them attached to a thin, isogrid aluminium wall (of course, addictional load-bearing structures can be added).
Title: Re: Speculation into what future versions of Dragon will involve
Post by: joek on 12/18/2012 02:53 am
Dragon is thought to have about 500 m/s delta-v, which should be more than enough for either a launch abort or a thruster-assisted touchdown after a mission. A purely propulsive touchdown might be more than that can handle.

Another indication... Assuming SpaceX has done their homework and 120klb thrust from the Superdracos is sufficient for launch abort (whatever DragonRider's weight), then given 1230-1290kg propellant (current Dragon) and an isp of 250-270 sec (postulated), produces ~5.6-6.4sec burn at full thrust (assuming my math is correct).

Either way - most of the list still stands even if one or two of the bullets is already in the Dragon 1.0

We could go on all day making lists of the work to go from Dragon cargo to Dragon crew--as indicated by the cost and time required for CCiCap et. al.  Yes, there will be significant changes, especially those dictated by the LAS.  No one is disputing that.  However, that doesn't change the fact that by all indications SpaceX will maximize the use of Dragon cargo to get to Dragon crew, and that a "from scratch" effort for Dragon crew is not needed or desired.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Magnus_Redin on 12/18/2012 08:34 pm
A merged upper stage and Dragon will only make sense once there is a significant flight history to prove that aborts at launch are only a statistical anomaly and can be ignored.

Otherwise you are back to creating a separating cabin and/or ejection seats, and you forfeit the advantage of a merged unit anyway.

Another idea would be to merge a reusable upper stage with the trunk for a low-margin reentry with the upper stage and high margin reentry with the manned part.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: cambrianera on 12/20/2012 05:38 pm
Tried to sketch an outline of Dragon with the estimated dimensions of SD.
Bigger than models we saw, but possible.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: meekGee on 12/21/2012 05:54 am
Seems reasonable as a "minimal change" outline.  Leaves room for the landing struts, too.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: solartear on 12/21/2012 06:38 pm
For landing, in principle, you only need as much as your terminal velocity, which for a largely empty aluminum can will be (IIANM) some 100 m/s. Cynically speaking, the rest will only make it easier for S&R to find the capsule if the landing went badly. 

OK - so if the stored impulse is already 500 m/s, I'm taking the "larger fuel tanks" out of the list.

How much extra margin will NASA require in case of extra wind, malfunctions, etc ?

Looks like they're planning to land it near populated areas, important launch facilities, jet flight paths, etc., and NASA wouldn't let SpaceX attempt to place that secondary payload with CRS1 into correct orbit because the oxygen only gave 95% instead of 99% chance of success. Granted the parachutes would make it less of a bullet, but they still don't want it suddenly dropping into middle of a city.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 12/21/2012 06:45 pm

How much extra margin will NASA require in case of extra wind, malfunctions, etc ?

Looks like they're planning to land it near populated areas, important launch facilities, jet flight paths, etc., and NASA wouldn't let SpaceX attempt to place that secondary payload with CRS1 into correct orbit because the oxygen only gave 95% instead of 99% chance of success. Granted the parachutes would make it less of a bullet, but they still don't want it suddenly dropping into middle of a city.

Apples and oranges.  CRS 1 was going to the ISS, which is NASA's jurisdiction.  Landing area safety is the FAA's jurisdiction.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: simonbp on 12/22/2012 02:13 pm
And something that they are already dealing with for Grasshopper flights.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: gin455res on 01/07/2013 07:43 am
Payload shrouds are often wider than the rockets that carry them. Is there any history of second stages being wider than the first stages that carry them?

What is the widest modified second stage that could be sensibly carried by falcon 9, and would a much squatter second stage; a)  re-enter the atmosphere more benignly - due to it being much fluffier, and having a larger base/mass ratio; and b) have a better mass fraction as it would be stubbier and have more efficient tanks that more closely resemble spheres not cylinders?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 01/07/2013 01:00 pm
Payload shrouds are often wider than the rockets that carry them. Is there any history of second stages being wider than the first stages that carry them?


See Titan IV Centaur and Delta III
Title: Re: Speculation into what future versions of Dragon will involve
Post by: ciscosdad on 01/07/2013 10:01 pm
I believe they can go to ~1.5 x the main stage diameter before they get unreasonable structural or aerodynamic stability probelems. I think I recall it being called a "hammerhead" configuration.
Not sure what sacrifices would need to be made to enable larger diameter ratios, or even if it is practically possible.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: solartear on 01/07/2013 11:54 pm
Could a used Falcon upper stage be used to de-orbit Dragon 2?  either its own (dormant for weeks/months) or later mission.

If there's a lot of margin leftover on upper stage, maybe Dragon could save more of it's own propellent for landing instead of de-orbit burn. Could it help or would too much propellant be used up just reconnecting to an upper stage?

Could be very useful for DragonLab to stay connected from launch until de-orbit burn completed.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 01/07/2013 11:57 pm
Payload shrouds are often wider than the rockets that carry them. Is there any history of second stages being wider than the first stages that carry them?

Several... And one example of an upcoming launcher that will do it is the Angara family, where all but the smallest version (Angara-1.1) will have upper stages of greater diameter than the boosters/1st stage. (see image below)

What is the widest modified second stage that could be sensibly carried by falcon 9, and would a much squatter second stage; a)  re-enter the atmosphere more benignly - due to it being much fluffier, and having a larger base/mass ratio; and b) have a better mass fraction as it would be stubbier and have more efficient tanks that more closely resemble spheres not cylinders?

Since a ~5m diameter payload fairing is planned, it they should be able to go to 5m at least.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 01/08/2013 12:32 am
Could a used Falcon upper stage be used to de-orbit Dragon 2?  either its own (dormant for weeks/months) or later mission.

If there's a lot of margin leftover on upper stage, maybe Dragon could save more of it's own propellent for landing instead of de-orbit burn. Could it help or would too much propellant be used up just reconnecting to an upper stage?

Could be very useful for DragonLab to stay connected from launch until de-orbit burn completed.

The LO2 would have boiled away in days, the batteries would be dead in hours and there is limited control gas for attitude control
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Robotbeat on 01/08/2013 12:49 am
I believe they can go to ~1.5 x the main stage diameter before they get unreasonable structural or aerodynamic stability probelems. I think I recall it being called a "hammerhead" configuration.
Not sure what sacrifices would need to be made to enable larger diameter ratios, or even if it is practically possible.
That isn't the limit at all. Atlas V has an available configuration for a 7.2m diameter fairing (for a 3.8m diameter rocket, giving a ratio of 1.9x), and that's not necessarily the upper limit:

Quote
Should a customer have a unique requirement to accommodate a larger payload, longer and wider payload fairings can be developed. Payload fairings as large as 7.2m (283 in.) in diameter and up to 32.3m (106 ft) in length have been considered. These larger fairings require moderate vehicle changes and modifications to the launch pad, which are limited mostly to secondary vertical processing facility structure. Please contact ULA for additional information on larger fairings.
http://www.ulalaunch.com/site/docs/product_cards/guides/AtlasVUsersGuide2010.pdf

So that's what's possible for a fairing. Probably wouldn't want such a huge upper stage, but if you have a special payload that needs a 7m diameter fairing, there's nothing in principle that says it /can't/ be launched on a Falcon 9.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 01/08/2013 12:51 am
the batteries would be dead in hours
Maybe the trunk power system could keep these topped up?

The LO2 would have boiled away in days
Has there ever been reasonably serious plans for gas-bladders/balloons to vent into in space?
Rube Goldbergy.  I know. 

there is limited control gas for attitude control
Maybe some from the vent gas bladders?

Follow-on question:  Does gaseous combustion in a chamber work in vacuum?  Better?  Worse?  Not at all?  Does the thrust transient from F1 flight 3 suggest it's fine?  Was that gaseous combustion?  Or liquid combustion?   
Title: Re: Speculation into what future versions of Dragon will involve
Post by: dragon44 on 01/08/2013 03:36 pm
Could a used Falcon upper stage be used to de-orbit Dragon 2?  either its own (dormant for weeks/months) or later mission.

If there's a lot of margin leftover on upper stage, maybe Dragon could save more of it's own propellent for landing instead of de-orbit burn. Could it help or would too much propellant be used up just reconnecting to an upper stage?

Could be very useful for DragonLab to stay connected from launch until de-orbit burn completed.

The LO2 would have boiled away in days, the batteries would be dead in hours and there is limited control gas for attitude control

What Jim said.

A different possibility is MMH and NTO tanks in the trunk. The trunk interconnect (claw) has electrical and fluid connections. The trunk MMH/NTO tanks could refill the Dragon tanks. It wouldn't take large pipes, just 'trickle charge' them.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: RanulfC on 01/08/2013 09:59 pm
I don't think we can read too much into Elon's 'flying saucer' comment. He probably means 'UFO' and there are lots of alleged shapes for UFOs.
I believe the quote was that it will look "like something from the future."

Unless there's another interview I'm not aware of, Elon never said flying saucer.
Well, bummer... there went MY "speculative-idea" on the matter ;)
http://www.nianet.org/rascal/forum2005/presentations/georgia_paper.pdf

Randy :)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 01/08/2013 10:14 pm
there went MY "speculative-idea" on the matter ;)
http://www.nianet.org/rascal/forum2005/presentations/georgia_paper.pdf

Randy :)
Nice find!  From a volume perspective, it seems crappier than a dragon shape.  From cross-range and larger cross-sectional area perspective, it's great (especially with the window-cover/aerosurface flaps/tabs).  Needs some superdracos and legs in there somewhere.  Looks like it's squat enough to fit beneath underpasses.  From a landed mass at Mars perspective, with those flaps, this pancake should outperform the current "red dragon" numbers by a lot.  It also allows for an easier egress of rovers and equipment.            Interesting direction.  Perhaps some of these ideas will make their way into dragon 2.  Maybe the craft would have the superdracos and legs on the window side, flip when subsonic using control surfaces, and come in fast for the "brown pants" landing. 

I'd love to hear some initial comments from the big guns here.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 01/09/2013 12:35 am
Nice find!  From a volume perspective, it seems crappier than a dragon shape.  From cross-range and larger cross-sectional area perspective, it's great (especially with the window-cover/aerosurface flaps/tabs).  Needs some superdracos and legs in there somewhere.  Looks like it's squat enough to fit beneath underpasses.  From a landed mass at Mars perspective, with those flaps, this pancake should outperform the current "red dragon" numbers by a lot.  It also allows for an easier egress of rovers and equipment.         

Useless for Mars and a bad shape for cargo
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 01/09/2013 12:37 am
a bad shape for cargo
Agreed.

Useless for Mars
Curious.  I would have expected some of the ideas would benefit atmospheric drag, cross-range, and downmass (with use of superdracos).
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jim on 01/09/2013 12:38 am
a bad shape for cargo
Agreed.

Useless for Mars
Curious.  I would have expected some of the ideas would benefit atmospheric drag, cross-range, and downmass.

Atmosphere is too thin
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 01/09/2013 01:01 am
Atmosphere is too thin

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015739_2011016739.pdf

Trim tab seems relevant.  These would be bigger. 
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Okie_Steve on 01/09/2013 09:00 pm
Just ran across this article about crew dragon testing.

http://venturebeat.com/2013/01/09/spacex-ccdev-updates/
Title: Re: Speculation into what future versions of Dragon will involve
Post by: ciscosdad on 01/09/2013 09:28 pm
Nice Find!
Look at the image of the Dragon. Looks like a forward pointing conical section has been added to the base. I wonder how different this would be aerodynamically to the current flat based version?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 01/09/2013 09:29 pm
Just ran across this article about crew dragon testing.

http://venturebeat.com/2013/01/09/spacex-ccdev-updates/
Cool. 

The picture with the wire-escape from the tower shows a high-bay and a low-bay hangar.  Any ideas why?  And whether the part we've seen construction pictures of is the high or low?
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jason1701 on 01/09/2013 09:45 pm
Nice Find!
Look at the image of the Dragon. Looks like a forward pointing conical section has been added to the base. I wonder how different this would be aerodynamically to the current flat based version?

What do you mean? The pressure vessel looks the same as this:
http://digitalvideo.8m.net/SpaceX/DragonRider/DragonPressureHull.jpg (http://digitalvideo.8m.net/SpaceX/DragonRider/DragonPressureHull.jpg)

Just ran across this article about crew dragon testing.

http://venturebeat.com/2013/01/09/spacex-ccdev-updates/
Cool. 

The picture with the wire-escape from the tower shows a high-bay and a low-bay hangar.  Any ideas why?  And whether the part we've seen construction pictures of is the high or low?

They recently finished constructing a high bay extension to the rear of the hangar.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Maciej Olesinski on 01/09/2013 09:48 pm
http://www.youtube.com/watch?v=IvVdD6qqROM

Few cool pictures ie. vertical draco test stand

And presentation: http://www.nasa.gov/pdf/718299main_CCP-Status-Update-1-9-13-finalSM.pdf

p.s. fancy space suit (Star Trek like ;))
Title: Re: Speculation into what future versions of Dragon will involve
Post by: mlindner on 01/09/2013 10:26 pm
Thread on the presser here.

http://forum.nasaspaceflight.com/index.php?topic=30772.75
Title: Re: Speculation into what future versions of Dragon will involve
Post by: e of pi on 01/09/2013 10:29 pm
Nice Find!
Look at the image of the Dragon. Looks like a forward pointing conical section has been added to the base. I wonder how different this would be aerodynamically to the current flat based version?
You mean the cutaway image? That's the pressure hull as it exists. The remaining volume is the systems for the thrusters and all that, and they stripped that from that image to better show the layout of the crew area.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: mlindner on 01/09/2013 11:06 pm

Few cool pictures ie. vertical draco test stand


Yeah friend of mine (intern) worked on the horizontal one. Apparently Musk pressed it on them to make a horizontal jury-rig to make a video of the super draco early on before they made a proper stand.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: mlindner on 01/10/2013 12:16 am
Nice Find!
Look at the image of the Dragon. Looks like a forward pointing conical section has been added to the base. I wonder how different this would be aerodynamically to the current flat based version?
You mean the cutaway image? That's the pressure hull as it exists. The remaining volume is the systems for the thrusters and all that, and they stripped that from that image to better show the layout of the crew area.

In the presentation they show an image of a dragon model in a heating chamber apparently testing something. It was stated that this is the new shape of the dragon. So there is apparently change in the outer hull of the dragon, unclear if there is any change to pressure vessel.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lars_J on 01/10/2013 12:53 am
Nice Find!
Look at the image of the Dragon. Looks like a forward pointing conical section has been added to the base. I wonder how different this would be aerodynamically to the current flat based version?
You mean the cutaway image? That's the pressure hull as it exists. The remaining volume is the systems for the thrusters and all that, and they stripped that from that image to better show the layout of the crew area.

In the presentation they show an image of a dragon model in a heating chamber apparently testing something. It was stated that this is the new shape of the dragon. So there is apparently change in the outer hull of the dragon, unclear if there is any change to pressure vessel.

... And just as many of us have said from the start, the outline of that Dragon model in the wind tunnel looks virtually identical to a cargo Dragon. Despite what many think, it won't look that different from the current Dragon.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Jason1701 on 01/10/2013 01:41 am

Few cool pictures ie. vertical draco test stand


Yeah friend of mine (intern) worked on the horizontal one. Apparently Musk pressed it on them to make a horizontal jury-rig to make a video of the super draco early on before they made a proper stand.

Possibly so Musk would have his own version of Boeing and Polaris's fancy hotfire video. :)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: ciscosdad on 01/10/2013 03:32 am
Nice Find!
Look at the image of the Dragon. Looks like a forward pointing conical section has been added to the base. I wonder how different this would be aerodynamically to the current flat based version?
You mean the cutaway image? That's the pressure hull as it exists. The remaining volume is the systems for the thrusters and all that, and they stripped that from that image to better show the layout of the crew area.

You are correct. I should have looked more closely.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: ciscosdad on 01/10/2013 03:41 am


I believe they can go to ~1.5 x the main stage diameter before they get unreasonable structural or aerodynamic stability probelems. I think I recall it being called a "hammerhead" configuration.
Not sure what sacrifices would need to be made to enable larger diameter ratios, or even if it is practically possible.
That isn't the limit at all. Atlas V has an available configuration for a 7.2m diameter fairing (for a 3.8m diameter rocket, giving a ratio of 1.9x), and that's not necessarily the upper limit:

Quote
Should a customer have a unique requirement to accommodate a larger payload, longer and wider payload fairings can be developed. Payload fairings as large as 7.2m (283 in.) in diameter and up to 32.3m (106 ft) in length have been considered. These larger fairings require moderate vehicle changes and modifications to the launch pad, which are limited mostly to secondary vertical processing facility structure. Please contact ULA for additional information on larger fairings.
http://www.ulalaunch.com/site/docs/product_cards/guides/AtlasVUsersGuide2010.pdf

So that's what's possible for a fairing. Probably wouldn't want such a huge upper stage, but if you have a special payload that needs a 7m diameter fairing, there's nothing in principle that says it /can't/ be launched on a Falcon 9.

Thanks for that. I stand corrected.
I assume there is some practical limit, though obviously 2x or greater.
Are the limitations structural or aerodynamic? Assuming one can live with the weight of a monstrous fairing. This I guess would apply more to Falcon Heavy and any versions of Dragon designed for that.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: ArbitraryConstant on 01/10/2013 05:09 am
... And just as many of us have said from the start, the outline of that Dragon model in the wind tunnel looks virtually identical to a cargo Dragon. Despite what many think, it won't look that different from the current Dragon.
It occurs to me that the pad abort test is also going to have to be damn near identical.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: RanulfC on 01/10/2013 05:45 pm
there went MY "speculative-idea" on the matter ;)
http://www.nianet.org/rascal/forum2005/presentations/georgia_paper.pdf

Randy :)
Nice find!

Thanks but I can't take credit for "finding" it :) I've been collecting as much information on the various "Lenticular Reentry Vehicle" designs for quite a while and had this one when it first came out. "Pushing" maybe... Not finding :)

As a "side" note the LRV design dates back to the initial Apollo studies and was considered for a long while before they went with the concical design.

Quote
From a volume perspective, it seems crappier than a dragon shape.  From cross-range and larger cross-sectional area perspective, it's great (especially with the window-cover/aerosurface flaps/tabs).  Needs some superdracos and legs in there somewhere.  Looks like it's squat enough to fit beneath underpasses.
"Volume" wise it is pretty cramped. This model would "carry" four passengers and a pilot. As for fitting under an underpass that's a "given" as it's ONLY 6-feet tall :)

This version would (IIRC my numbers) would just barely "fit" onto the Falcon-9 body in the "standard" heat shield-down mode and for more room you could always increase the diamter and move to a "sideways" connection as is suggested in the concept.

No "Super-Draco's" needed as they design lands by parachute for final touch down. (You can look up "LRV water landing tests" to see why you want to have a parachute, just in case :) ) and no landing legs are needed as the heat-shield acts as the landing surface. (In the same NASA work as the water landing tests above they did studies on using a "solid" heat shield as a landing surface for flying landings. Turns out it worked pretty damn good actually, but then again Elon doesn't like "wings" or flying things as far as I can tell :) )

Quote
From a landed mass at Mars perspective, with those flaps, this pancake should outperform the current "red dragon" numbers by a lot.  It also allows for an easier egress of rovers and equipment.
Yes, but...  :)
As Jim notes a "Dragon" size vehicle wouldn't generate much lift in the Martian atmosphere. Aerobraking is a possible advantage, especially if you make the entire "vehicle" bigger, but that is far and away getting away from the topic here.
(And deployment would require some way of getting the equipment over the "lip" and then down to the ground. Shorter distance "down" but longer and more complicated distance "out" as it were :) )

Quote
Interesting direction.  Perhaps some of these ideas will make their way into dragon 2.
No chance there :) As noted Elon doesn't like "flying" things so if "wings" are useless then a "lifting-body" is probably worse ;)

More on subject though, my understanding was that once the second stage got the Dragon on the "way" to the ISS it could/would be cut lose to reenter (return in the reusable version) and the Dragon with SDs would have enough delta-V to do everything else?

Randy
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lar on 01/10/2013 07:08 pm
Re the Venture Beat article.... Why are new space suits on the list of tasks SpaceX has to execute? Wouldn't they use existing suits? (yes, they're in the slides but ... why?)
Title: Re: Speculation into what future versions of Dragon will involve
Post by: JBF on 01/10/2013 07:38 pm
Re the Venture Beat article.... Why are new space suits on the list of tasks SpaceX has to execute? Wouldn't they use existing suits? (yes, they're in the slides but ... why?)

They will need suits for the test crew. Who's existing suits would they use? Most are custom per astronaut.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Robotbeat on 01/10/2013 07:45 pm
Re the Venture Beat article.... Why are new space suits on the list of tasks SpaceX has to execute? Wouldn't they use existing suits? (yes, they're in the slides but ... why?)

They will need suits for the test crew. Who's existing suits would they use? Most are custom per astronaut.
Also, the space suits generally need to be different for different types of spacecraft. Or so I've read, according to a space suit manufacturer.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lar on 01/10/2013 07:58 pm
Re the Venture Beat article.... Why are new space suits on the list of tasks SpaceX has to execute? Wouldn't they use existing suits? (yes, they're in the slides but ... why?)

They will need suits for the test crew. Who's existing suits would they use? Most are custom per astronaut.
Also, the space suits generally need to be different for different types of spacecraft. Or so I've read, according to a space suit manufacturer.

I can see, if one needs custom per astronaut suits, that one would need new instances but I'm not clear on why new designs are needed.

What causes suits not to be adaptable for multiple craft types? Is this a  common thing with other pressurised suits like flight suits? Does an F16 flight suit differ in substantial ways from an F15 flight suit?

I'm just surprised that SpaceX would go to this expense.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: go4mars on 01/10/2013 10:20 pm
No "Super-Draco's" needed as they design lands by parachute for final touch down...and no landing legs are needed as the heat-shield acts as the landing surface.
Superdraco's and legs may be of benefit for the same reasons they are of benefit to propulsive-landing/abort dragon.

Elon doesn't like "wings" or flying things as far as I can tell :) )  As noted Elon doesn't like "flying" things so if "wings" are useless then a "lifting-body" is probably worse ;)
Context.  Pretty sure he likes wings.  He used to have one of these:
http://en.wikipedia.org/wiki/Aero_L-39
And I think he still has one of these:
http://en.wikipedia.org/wiki/Dassault_Falcon_900

deployment would require some way of getting the equipment over the "lip" and then down to the ground. Shorter distance "down" but longer and more complicated distance "out" as it were
Maybe so.  I was thinking egress would include a walk or drive down the open tabs.   
Title: Re: Speculation into what future versions of Dragon will involve
Post by: simonbp on 01/11/2013 03:35 pm
I don't think we can read too much into Elon's 'flying saucer' comment. He probably means 'UFO' and there are lots of alleged shapes for UFOs.
I believe the quote was that it will look "like something from the future."

Unless there's another interview I'm not aware of, Elon never said flying saucer.
Well, bummer... there went MY "speculative-idea" on the matter ;)
http://www.nianet.org/rascal/forum2005/presentations/georgia_paper.pdf

Randy :)

The GE Apollo R-3 design has you beat by a few decades...
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Halidon on 01/11/2013 11:34 pm
Am I crazy or are those guys naked? I wasn't aware GE proposed a spacecraft with its own Sauna onboard.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: IRobot on 01/12/2013 12:37 am
Am I crazy or are those guys naked?
You are not crazy, you are horny :D
Title: Re: Speculation into what future versions of Dragon will involve
Post by: Lar on 01/12/2013 06:24 am
Am I crazy or are those guys naked?
You are not crazy, you are horny :D
I thought spacemen got all the chicks.

That is one wacky craft, thanks for posting it.
Title: Re: Speculation into what future versions of Dragon will involve
Post by: CuddlyRocket on 01/12/2013 08:42 am
I can see, if one needs custom per astronaut suits, that one would need new instances but I'm not clear on why new designs are needed. ... I'm just surprised that SpaceX would go to this expense.

Given SpaceX's mantra of reducing costs through reusability and modularity, I suspect that they would have at least looked into the possibility of designing space suits that can - to a greater or lesser extent - be reused by different people and have component parts swappable out in case of damage etc.

After all, these won't be EVA space suits; they'll be worn during ascent and descent where all they need to do is protect the wearer from depressurisation and flames.