Author Topic: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 2  (Read 1873918 times)

Online Chris Bergin

Time for thread 2 as thread 1 was becoming convoluted (long threads tend to, and we hate trimming threads - so left intact and here's a fresh one to get the focus back).

Main Article:
http://www.nasaspaceflight.com/2014/11/spacex-autonomous-spaceport-drone-ship/
(Also contains links to other articles covering reusability tech).

ASDS General Discussion Thread 1:
http://forum.nasaspaceflight.com/index.php?topic=36140.0

ASDS Update Thread (for closer the time):
http://forum.nasaspaceflight.com/index.php?topic=36167.0

SpaceX Articles:
http://www.nasaspaceflight.com/tag/spacex/

L2 SpaceX Section:
http://forum.nasaspaceflight.com/index.php?board=55.0


Stay focused. No excuse to rambling off into other areas of reuse etc when we have so many threads on what is the largest forum level discussion of SpaceX on the entire bloody internet! ;D

Offline deruch

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Quote from: The Amazing Catstronaut link=topic=36140.msg1302393#msg1302393
Edit: Does anyone have a link to where I'd find a (rough) model for the aquadynamic properties for the  ASDS?

Brought over from thread 1.
In theory, there is no difference between theory and practice.  But, in practice, there is.  --Jan van de Snepscheut

Online symbios

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Quote from: The Amazing Catstronaut link=topic=36140.msg1302393#msg1302393
Edit: Does anyone have a link to where I'd find a (rough) model for the aquadynamic properties for the  ASDS?

Brought over from thread 1.

It's based on a flat bottom, flat fronted barge... it has the aquadynamic properties of a brick... (if a brick would float)
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Offline Avron

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Quote from: The Amazing Catstronaut link=topic=36140.msg1302393#msg1302393
Edit: Does anyone have a link to where I'd find a (rough) model for the aquadynamic properties for the  ASDS?

Brought over from thread 1.

It's based on a flat bottom, flat fronted barge... it has the aquadynamic properties of a brick... (if a brick would float)

BargeX -- we assume is a group of barges assembled into one boat. now a boat can have a flat bottom, can a Ship also have the same shape.. Elon noted Ship.

Offline llanitedave

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Modern ships do have flat bottoms in cross section.
"I've just abducted an alien -- now what?"

Offline CameronD

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Quote from: The Amazing Catstronaut link=topic=36140.msg1302393#msg1302393
Edit: Does anyone have a link to where I'd find a (rough) model for the aquadynamic properties for the  ASDS?

Brought over from thread 1.

It's based on a flat bottom, flat fronted barge... it has the aquadynamic properties of a brick... (if a brick would float)

Do you have any evidence to support that claim??  From the aerial photos made available it clearly could also have a catamaran hull.
« Last Edit: 12/15/2014 12:42 AM by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline darkenfast

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The hull appears to be a stock barge.  No need to make things more complicated and expensive than they need to be.

Offline CameronD

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The hull appears to be a stock barge.  No need to make things more complicated and expensive than they need to be.

If your requirement is maximum stability (not just the ability to carry stuff), then yes there probably IS a need to make things more complicated and expensive.
« Last Edit: 12/15/2014 01:31 AM by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline Nomadd

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 Maybe if things pan out SpaceX will have Austal make them a nice 45 knot cat. But I think it's a good bet this one is just built onto a used, flat bottomed barge.

Offline Doesitfloat

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The hull appears to be a stock barge.  No need to make things more complicated and expensive than they need to be.

If your requirement is maximum stability (not just the ability to carry stuff), then yes there probably IS a need to make things more complicated and expensive.

This isn't a government contract. Why spend a dollar when the nickel solution works fine.
They could absolutely spend exponentially more money on a marginally more stable platform.

Source: Principles of Naval Architecture: Volume III Motions in Waves and Controllability

Offline Zed_Noir

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Youtube user KerbalEssences uploaded this amusing KSP video of a F9R bargeslam.  :)



mods: move post to more appropriate thread if required

Offline Dudely

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Someone linked to that on a Google+ post as "proof" SpaceX will be able to do it. . . I didn't even know what to say.

Offline chalz

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One thing it did do well was illustrate, in Musk's words, how small the barge looks from space.

Offline georgegassaway

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Something that occurred to me, which  do not know if it has been discussed before. It involves Falcon Heavy, but I think it belongs in this thread as I have begun to wonder if the landing barge  (or Autonomus Spaceport Drone Ship) may have been intended all along for Falcon Heavy anyway.

The idea involves three things:

1 - A place to land at sea, which now exists with the barge / ASDS.

2 - Permission to land stages back at the Cape.  That permission is pending, seems likely, the success of the landing attempts on the barge/ASDS perhaps being the eventual deciding factor.

3 - And finally, Falcon Heavy being launched, trying to recover all three of the Falcon first stage cores.

Due to the cross-feed of fuel/oxidizer from the two outer cores, the center core will be nearly full when the outer cores separate. So, the center core will travel a lot farther downrange, at a much greater velocity, than the existing Falcon-9 first stage is when it finally stages.  So, while it is possible for Falcon-9 to fly the first stage back to land (at a bigger payload hit than landing far out at sea), the much  greater downrange distance and velocity of the center core of Falcon Heavy would seem to be impractical to fly it back to the Cape.

So, SpaceX has probably had good reason to have the barge/ASDS eventually, to support recovery of the center core of Falcon Heavy. And there probably have been a lot of people who have realized this part in the last few weeks with release of existence of the barge / ASDS.

But the other thing that occurred to me more recently is how much easier it should be to have the two outer cores fly back to land, than for the Falcon-9 first stage.  Because the outer cores will be providing about 1/3 of their fuel to the center core. So when they need to shut down and separate,  their ballistic path will not be traveling nearly as far downrange, and not nearly as fast, as Falcon 9's first stage. 

Let's say a guesstimate in the ballpark of about 60% as far and 60% as fast? Perhaps even closer to 50%  So they will not need as much fuel to be able to thrust back to the Cape as a Falcon-9 first stage would.

About the only fly in the ointment of the newly announced barge / ASDS, and using if to recover the Falcon Heavy core, is that the ballistic path may cause it to land many hundreds more miles downrange, perhaps over 1000 (guesstimate).  So the distance would mean a long trip back, several days, which may encounter some pretty bad sea conditions, even storms, that the current version may not be equipped to handle.

 So, It'll be interesting to see if they have already accounted for that sort of thing, ways to secure it against bad weather and sea conditions for much longer  trips back rather than Falcon-9 recovery which may take only a day or so. 

At first it had sounded like all they were doing was a temporary test barge for a few flights due to lack of permission to land at the Cape.  But it may be that it is an inevitable necessity long-term to support Falcon Heavy recovery.

- George Gassaway

Offline Nomadd

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Something that occurred to me, which  do not know if it has been discussed before. It involves Falcon Heavy, but I think it belongs in this thread as I have begun to wonder if the landing barge  (or Autonomus Spaceport Drone Ship) may have been intended all along for Falcon Heavy anyway.

- George Gassaway
You could have saved a lot of typing by keeping up. SpaceX has already said the barge is for FH center cores and F9 cores where they can't afford the RTLS payload penalty.

Offline MTom

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Something that occurred to me, which  do not know if it has been discussed before.
...

Something like this?   ;)


Online e of pi

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So, the barge has been seen departing in the care of a tug and the company o a ship carrying some assorted dishes, per Spaceflight now. Seems to pretty conclusively prove that the flight deck is right on top of the hull, and that it's a cheap, simple, standard barge with a flight deck welded on, not a more lavish setup like some have speculated.

Offline matthewkantar

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Very exciting, the post reveals the names of the barge, the tug, probably the support ship. Should be able to watch the progress of the operation in real time.

Matthew

Offline robertross

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So, the barge has been seen departing in the care of a tug and the company o a ship carrying some assorted dishes, per Spaceflight now. Seems to pretty conclusively prove that the flight deck is right on top of the hull, and that it's a cheap, simple, standard barge with a flight deck welded on, not a more lavish setup like some have speculated.
Thanks for the link

Of note, I see on deck:
1) The landing pad mostly surrounded by an I-beam style structure, to contain the rocket on the pad and/or aid in containing water to aid in cooling the deck surface from exhaust gases

2) 3 of (though probably 4) diesel powered units, grey coloured, c/w fire extinguishers, obviously for the thrustmaster positioning hydraulic units. Also located directly in front of them are 'massive' (relatively speaking) cooler units (likely for the hydraulics, as the engine coolers are self-contained).

3) Binocular set on top of a container, perhaps IR or motion stabilized? Certainly weatherized in an enclosure meant to move

4) 1/2 size Radar and communications containers fore & aft

5) 4 of unknown yellow containers. Likely Diesel fuel though, for the diesel-powered units (as they stand right beside them)

6) 2 of unknown full-size containers, 2 each fore & aft, likely for storage and/or personnel protection from the elements
 
7) the landing surface is surrounded by a railing, strung with galvanized aircraft cable (likely) and/or chain

8_ Some weird looking cherry picker (mfr: TEUPEN), with (rubber?) track drive c/w outrigger legs

9) work lights
« Last Edit: 12/16/2014 11:38 PM by robertross »
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Offline CameronD

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There's a lot more junk on deck than I'd expected.  They must be mighty confident of a pin-point landing.  :)


8_ Some weird looking cherry picker (mfr: TEUPEN), with (rubber?) track drive c/w outrigger legs

That would be one of these - presumably for safeing the landed stage:



http://www.teupen.com/en/access-platforms/leo-range/leo-23-gt.html
« Last Edit: 12/17/2014 12:03 AM by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

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