Author Topic: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 1  (Read 240120 times)

Offline dglow

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #180 on: 11/24/2014 05:58 pm »
However, it seems one element of this that will need manual operations is to get the rocket onto the TEL in the first place - the very thing that will be an issue in barge operations.

cheers, martin

If the rocket no longer needs a TEL, then the issue goes away.  I think this sort of feature is on the critical path for the F9 replacement whenever we hear about it.

Obviously, they'll need payload integration of some sort at the beginning of the launch automation process where the payload provider doesn't have autonomous processes, but the rest could be automated, including the drive from Hawthorne to the launch site if you believe Musk's autonomous vehicle predictions.

Interesting observation. This may be an odd question, but with the exception of initial construction and road transport might we be looking at the end of horizontal storage and integration?

With reusability and flyback established, are there enduring reasons for cores to go horizontal again? Assume years down the road and envision many of the automated systems described upthread: if the need to transport horizontally is obviated by flyback, will that alter SpaceX's preference for horizontal integration?

Offline rpapo

Even if the rocket is entirely integrated already, the rocket is certainly easier to work on in the horizontal position, especially with the "rocket rotisserie" arrangement that SpaceX has devised (or copied from somebody else).  Periodic inspections will probably always be required, even if there aren't new things to fasten to the rocket's sides.
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Online jaufgang

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #182 on: 11/24/2014 06:12 pm »
I updated the image and I think it is more accurate now, the circles were a bit elliptical in the last one

edit - updated with added accuracy... at least thats what it seems to me


here's a further suggestion:  add dotted lines along the hinges where the side wings fold up (or down?) and the 100' width measurement?  Great work.
« Last Edit: 11/24/2014 06:15 pm by jaufgang »

Offline IRobot

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #183 on: 11/24/2014 06:23 pm »

It is much cheaper to send an heli from shore than to keep a boat on standby for days, although I am not exactly sure how far the barge will be.

You're going to need a boat there anyway, to propel the barge.  And the boat will probably have the crane on it.
The barge is self propelled, at least for position keeping. Electric motors for position keeping require a large diesel generator. So if the barge has enough diesel, the barge is self propelled. No need for a boat.

Offline sghill

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #184 on: 11/24/2014 06:24 pm »
I updated the image and I think it is more accurate now, the circles were a bit elliptical in the last one

edit - updated with added accuracy... at least thats what it seems to me


here's a further suggestion:  add dotted lines along the hinges where the side wings fold up (or down?) and the 100' width measurement?  Great work.

I don't know that the wings fold up.  I think they jut out to the side of the hulls like the overhang on an aircraft carrier deck (sorry, I know that wasn't completely CRS-5 related!)
« Last Edit: 11/24/2014 06:25 pm by sghill »
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Offline IRobot

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #185 on: 11/24/2014 06:26 pm »
Given this barge is going to be stationed 100nm+ off shore it will need a tug which will double as command ship. I don't think the propulsion system is designed for long haul travel in open sea.
Not necessarily. I've worked in a large ship with 6 of these electric motors for position keeping. Internally it had 2 huge diesel generators to power the electrics. It could use the 6 electric motors for moving, but speed would be reduced to 11kn. So they added 2 extra diesel engines to achieve 17kn, but the electric motors were enough for propelling it.

Online Robotbeat

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #186 on: 11/24/2014 06:31 pm »
Given this barge is going to be stationed 100nm+ off shore it will need a tug which will double as command ship. I don't think the propulsion system is designed for long haul travel in open sea.
I see the need to have people on hand to fix stuff and lash stuff down (and to make dang sure it's safe navigating in harbor, although not /strictly/ needed from a technical standpoint), but I see no fundamental reason why you'd need a tug out at sea. These systems ARE made for long haul in the open sea. And in fact, with 4 different maneuverable thruster pods, you have tons of redundancy (though fine control would be lost if enough pods are lost).

...such thruster pods would be less efficient for trans-oceanic cargo trips compared to a streamlined hull and screw, but that's just talking about the amount of fuel required.
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Offline TripD

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #187 on: 11/24/2014 06:38 pm »
Agree with Sghill here.  Although the ability to pass through the Panama Canal would lend flexibility to  their logistics, SpaceX may have chosen otherwise.  Nice work on that reference photo btw.

Offline Llian Rhydderch

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #188 on: 11/24/2014 06:56 pm »

It is much cheaper to send an heli from shore than to keep a boat on standby for days, although I am not exactly sure how far the barge will be.

You're going to need a boat there anyway, to propel the barge.  And the boat will probably have the crane on it.
The barge is self propelled, at least for position keeping. Electric motors for position keeping require a large diesel generator. So if the barge has enough diesel, the barge is self propelled. No need for a boat.

I think the Thrustmaster announcement I read on Saturday said these were diesel-hyrdraulic powered units, not diesel-electric, as are some other azimuth thruster designs.
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Offline Nomadd

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #189 on: 11/24/2014 07:03 pm »

I think the Thrustmaster announcement I read on Saturday said these were diesel-hyrdraulic powered units, not diesel-electric, as are some other azimuth thruster designs.
They are. I was just working on one a few weeks ago. Ours are completely electricity free and started by compressed air. It makes them intrinsically safe in explosive environments. That could be a factor here.
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Offline Dave G

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #190 on: 11/24/2014 07:03 pm »
The barge is self propelled, at least for position keeping. Electric motors for position keeping require a large diesel generator. So if the barge has enough diesel, the barge is self propelled. No need for a boat.
Doesn't seem very practical.

The lack of a pilothouse and its rectangular profile make it certain it will be towed into position by a tug and then detached for the actual landing exercise before being tugged back to port. A tugboat or similar support ship will be positioned not too far away.
Sounds a lot more likely.

Online jaufgang

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #191 on: 11/24/2014 07:40 pm »
I updated the image and I think it is more accurate now, the circles were a bit elliptical in the last one

edit - updated with added accuracy... at least thats what it seems to me


here's a further suggestion:  add dotted lines along the hinges where the side wings fold up (or down?) and the 100' width measurement?  Great work.

I don't know that the wings fold up.  I think they jut out to the side of the hulls like the overhang on an aircraft carrier deck

I interpreted Musk's tweet to mean that the wings were extensible:
Quote
Base is 300 ft by 100 ft, with wings that extend width to 170 ft.

I suppose my interpretation is not necessarily implied, and  the statement could be interpreted to mean simply that the monolithic top deck overhangs the sides by 30 feet on each side.  But I'm not sure that he'd call them "wings" if that were the case, it makes them sounds like a distinct structure.

Agree with Sghill here.  Although the ability to pass through the Panama Canal would lend flexibility to  their logistics, SpaceX may have chosen otherwise.  Nice work on that reference photo btw.

There could be other motivations for making the wings collapsible....  fitting into the shipyard during construction/maintenence for example or constraints of the harbour slip? 


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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #192 on: 11/24/2014 07:40 pm »
The barge is self propelled, at least for position keeping. Electric motors for position keeping require a large diesel generator. So if the barge has enough diesel, the barge is self propelled. No need for a boat.
Doesn't seem very practical.

The lack of a pilothouse and its rectangular profile make it certain it will be towed into position by a tug and then detached for the actual landing exercise before being tugged back to port. A tugboat or similar support ship will be positioned not too far away.
Sounds a lot more likely.
Why the extra expense of a tug if you're already self-propelled? That doesn't make sense. The pods are quite powerful, easily powerful enough for putting itself in position. A support ship, sure, but why a tug?
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Offline sanman

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #193 on: 11/24/2014 07:48 pm »
It would probably be best for the barge to be escorted, wouldn't it?

You just can't give the thing GPS waypoints and entrust it with your valuable cargo unsupervised, can you? Sometimes stuff malfunctions and breaks down, and people have to be nearby to come fix it.

It seems like for those early carry-backs, where the barge is carrying the rocket stage back to land, then that stage is going to have been purged of propellants/etc to make it safe, and so you could afford to have personnel stationed on the barge without their lives being in danger. Is that perhaps what the initial CRS-5 landing mission will be like?

If not, then what will the CRS-5 landing/post-landing be like?

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #194 on: 11/24/2014 07:53 pm »
Look, sometimes new technology changes things. With a self-powered barge, you don't need a tug. A support vessel with crew, sure, but you don't need to tow the vessel into place. And yes, you /can/ just give it GPS navpoints (combined with dead-reckoning short-term backup).

Also, hydraulic power transmission is a pretty good idea. Hydraulic motors are very power-dense.
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Offline sghill

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #195 on: 11/24/2014 08:05 pm »
Look, sometimes new technology changes things. With a self-powered barge, you don't need a tug. A support vessel with crew, sure, but you don't need to tow the vessel into place. And yes, you /can/ just give it GPS navpoints (combined with dead-reckoning short-term backup).

Also, hydraulic power transmission is a pretty good idea. Hydraulic motors are very power-dense.

I agree.  If the head of this company is at the forefront of autonomous vehicle deployment (and some of their current vehicles are being sold as "autonomous-ready"), it shouldn't be much of a stretch to think of something as slow as a barge moving in and out of a port on it's own.

Mind you, the boat operator's liability doesn't change a bit, but cameras and sensors on a telescoping stalk can do just as well (perhaps better) as Captains Schettino, Lee, and Hazlewood.

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Offline Jim

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #196 on: 11/24/2014 08:11 pm »

With reusability and flyback established, are there enduring reasons for cores to go horizontal again? Assume years down the road and envision many of the automated systems described upthread: if the need to transport horizontally is obviated by flyback, will that alter SpaceX's preference for horizontal integration?


Easier access and easier transport.  Landing pad, launch pad and hangar are not the necessarily the same facility or in the same area.

Offline Jdeshetler

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #197 on: 11/24/2014 08:12 pm »
The barge is self propelled, at least for position keeping. Electric motors for position keeping require a large diesel generator. So if the barge has enough diesel, the barge is self propelled. No need for a boat.
Doesn't seem very practical.

The lack of a pilothouse and its rectangular profile make it certain it will be towed into position by a tug and then detached for the actual landing exercise before being tugged back to port. A tugboat or similar support ship will be positioned not too far away.
Sounds a lot more likely.
Why the extra expense of a tug if you're already self-propelled? That doesn't make sense. The pods are quite powerful, easily powerful enough for putting itself in position. A support ship, sure, but why a tug?

From the brochure, the depth of the props varied from 18' to 50' deep when in running position. Maybe they pick the middle size, 30' to keep the operating cost down by not using tugs regardless of which deep waterways they go.

The Brownsville Ship Channel has an authorized depth of 42 feet.  The Turning Basin, has a depth of thirty-six feet and a width of 1,200 feet.

Port Canaveral's depths ranging from 35-40 ft.



Offline grakenverb

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #198 on: 11/24/2014 08:31 pm »
Regarding autonomous operation of the barge, the US Coast Guard wouldn't let it happen just yet:

http://www.ecfr.gov/cgi-bin/text-idx?rgn=div5&node=46:1.0.1.2.15#se46.1.15_1101
« Last Edit: 11/24/2014 08:32 pm by grakenverb »

Offline rcoppola

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread
« Reply #199 on: 11/24/2014 08:39 pm »
I see no issue with a small support team on the barge (2 people), going out to the coordinates, transferring to a support ship that will then be standing by a few miles? away. At least for the initial run(s).

Even for something as mundane but important as checking to ensure the deck is cleared of any debris that may have come loose or blown aboard, etc. I'd think they would inspect the deck as a matter of mission check-list.

I wonder when the barge will depart for a Dec. 16th debut landing? How long do we think it will be "on-site" before the landing attempt. 2 to 3 days?
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