Author Topic: SpaceX's Autonomous Spaceport Drone Ship Updates and Discussion Thread 3  (Read 1424023 times)

Offline Cheapchips

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Aren't the current droneships only towed due to regulation, rather than a technical limitation?

Offline abaddon

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Aren't the current droneships only towed due to regulation, rather than a technical limitation?
No, they are not capable of reaching their deployment location on their own.

Offline CameronD

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Aren't the current droneships only towed due to regulation, rather than a technical limitation?
No, they are not capable of reaching their deployment location on their own.

FWIW, the ABS Barge Rules indicate that thrusters and similar propulsion systems are permitted only for 'short field moves' (consisting of moving the unit from one work location to another location within the same area of operation, that takes no longer than 12 hours and is conducted in daylight hours).

To do anything more than the above would require re-classification (as a "vessel" of some kind) and would require significant modification to meet all of the additional requirements for propulsion, navigation and accommodation.
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 biosehnsucht

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Aren't the current droneships only towed due to regulation, rather than a technical limitation?
No, they are not capable of reaching their deployment location on their own.

Rules & regulations aside, I'm sure if you just told them to hold position at their destination, and they didn't run out of fuel getting there (their position holding thrusters won't be the most efficient means of transport, I'm sure), or run into any other vessels or any land masses (as they don't have any kind of collision avoidance or map based navigation I'm sure), they'd get there eventually. So technically it should be possible, but only within fuel range (and in theory could be refueled at sea, but at that point why not just tow them anyways), and when nothing gets between them and their destination.

Obviously, with no way to avoid a collision towing them to at least the approximate location is the obvious course of action, never mind whether they would have had enough fuel to make it on their own, or be legal, etc.

Offline aero

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Aren't the drone ships just converted barges? Barges with station holding gear bolted on to hold it against winds and currents. That doesn't include a wheel and rudder for steering or a powertrain for propulsion.
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Offline speedevil

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Aren't the drone ships just converted barges? Barges with station holding gear bolted on to hold it against winds and currents. That doesn't include a wheel and rudder for steering or a powertrain for propulsion.
You don't actually need a wheel or rudder.
And if you can stationkeep in 8 knots, you can move at 8 knots (not against a current).

With 10000 ton capacity or so, there is plenty of fuel. However, for regulatory and other reasons explained upthread, having them actually self-ferry would be silly.

Offline CameronD

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Yes, there is no technical reason they can't self-ferry.. but many reasons they don't.  Safety of navigation for other vessels and safety of the environment are two biggies.

Taken to the extreme, you might be wondering why modern cargo ships cannot be fully automated?  After all, without anyone on board (a) there'd be no crew to pay, (b) no accommodation space needed so extra cargo could be loaded and (c) no expensive and dangerous rescues if the ship gets caught in a storm - all meaning much higher efficiency and better returns for the operators.  Sounds great, yes??  And many people (the Port of Singapore Authority to name one in this region) seriously considered doing this as far back as the 1990's - long before development of the self-driving tech we have now.  Interestingly, with so much money at stake if it worked, this application was one of the reasons AIS was developed in the first place... but the idea died the second they read the COLREGs and considered the implications.
« Last Edit: 11/18/2018 10:13 pm 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 docmordrid

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Yes, there is no technical reason they can't self-ferry.. but many reasons they don't.  Safety of navigation for other vessels and safety of the environment are two biggies.

Taken to the extreme, you might be wondering why modern cargo ships cannot be fully automated?  After all, without anyone on board....

Rolls Royce and several other companies are working on remotely-sailed (drone) cargo ships, and the 79.5m autonmous container feeder YARA Birkeland is being built,  so....
« Last Edit: 11/18/2018 10:30 pm by docmordrid »
DM

Offline CameronD

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Yes, there is no technical reason they can't self-ferry.. but many reasons they don't.  Safety of navigation for other vessels and safety of the environment are two biggies.

Taken to the extreme, you might be wondering why modern cargo ships cannot be fully automated?  After all, without anyone on board....

Rolls Royce and several other companies are working on remotely-sailed (drone) cargo ships, and the 79.5m autonmous container feeder YARA Birkeland is being built,  so....

..with a max speed of 10kts (most similar vessels do +20kts) and a dedicated route (like a big ferry) for the reasons I mentioned above, we'll see how far they can successfully push the envelope, won't we??  :)


EDIT:  As for the others, don't hold your breath - you'll suffocate.  Elon will be landing on Mars long before those concepts ever see the water.
« Last Edit: 11/18/2018 11:55 pm 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 Lar

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..., and the 79.5m autonmous container feeder YARA Birkeland is being built,  so....
Hasn't it been "being built" for quite a while now?
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Offline Llian Rhydderch

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..., and the 79.5m autonmous container feeder YARA Birkeland is being built,  so....
Hasn't it been "being built" for quite a while now?

It seems to have been ordered in 2017, but no record of its keel being laid or launching since then.  Just renders and a video made by the company, along with execs making statements. 

Seems somewhat like a number of the rocket and in-space concepts we deal with all the time on NSF.   ;)

Re arguments from authority on NSF:  "no one is exempt from error, and errors of authority are usually the worst kind.  Taking your word for things without question is no different than a bracket design not being tested because the designer was an old hand."
"You would actually save yourself time and effort if you were to use evidence and logic to make your points instead of wrapping yourself in the royal mantle of authority.  The approach only works on sheep, not inquisitive, intelligent people."

Offline Nydoc

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There is a barge in these pictures.

https://twitter.com/LilyRubenstein/status/1078120710525018112

(credit to Twitter user @LilyRubenstein )

Offline Tommyboy

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There is a barge in these pictures.

https://twitter.com/LilyRubenstein/status/1078120710525018112

(credit to Twitter user @LilyRubenstein )
And those orange supports on the barge are exactly the same as under the fairings on shore. Seems like a SpaceX barge to me.

Offline Cowboy Dan

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Think the barge is being used in cahoots with the fairing drop tests out of Port LA. Tug Sir Richard pulls the fairing loaded barge to drop site (Catalina Island-ish), from which a commercial Blackhawk helicopter latches to fairing. Bird climbs to height while SpX ship Mr Steven maneuvers into place.

Offline Nydoc

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Think the barge is being used in cahoots with the fairing drop tests out of Port LA. Tug Sir Richard pulls the fairing loaded barge to drop site (Catalina Island-ish), from which a commercial Blackhawk helicopter latches to fairing. Bird climbs to height while SpX ship Mr Steven maneuvers into place.
Would this be the vessel of which Elon hinted as "A Shortfall of Gravitas" (maybe re-purposed for fairing use) or is that a different vessel?

Offline AC in NC

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Would this be the vessel of which Elon hinted as "A Shortfall of Gravitas" (maybe re-purposed for fairing use) or is that a different vessel?

No.  The ASDS beam is 170ft.  Mr Steven is 34ft.  That barge is closer to Mr Steven than an ASDS.

Online edzieba

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Would this be the vessel of which Elon hinted as "A Shortfall of Gravitas" (maybe re-purposed for fairing use) or is that a different vessel?

No.  The ASDS beam is 170ft.  Mr Steven is 34ft.  That barge is closer to Mr Steven than an ASDS.
The Marmac 300 series has a 100' beam, the additional width in their ASDS role is from the 'wings' welded to the sides. This barge is still too small to be a pre-refit ASDS of the same pattern, unless SpaceX are confidant enough of landing CEP to downsize and also have some reason not to continue to use their already converted barges.

Offline AC in NC

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The Marmac 300 series has a 100' beam, the additional width in their ASDS role is from the 'wings' welded to the sides. This barge is still too small to be a pre-refit ASDS of the same pattern, unless SpaceX are confidant enough of landing CEP to downsize and also have some reason not to continue to use their already converted barges.

Thanks!  I'm a little surprised I'd never picked up that point before but maybe I got here late.

Seen clearly below:

Offline IntoTheVoid

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The Marmac 300 series has a 100' beam, the additional width in their ASDS role is from the 'wings' welded to the sides. This barge is still too small to be a pre-refit ASDS of the same pattern, unless SpaceX are confidant enough of landing CEP to downsize and also have some reason not to continue to use their already converted barges.

Thanks!  I'm a little surprised I'd never picked up that point before but maybe I got here late.

Seen clearly below:

Without presuming when you arrived, the wings were quite evident when Marmac 300 (JRTI I) was retired and Marmac 303 (JRTI II) took over. The wings were removed from 300 and placed on 303 and then carried through the (un-expanded) Panama Canal to the west coast. The trip and the conversion from Marmac 303 to JRTI II took many weeks and pages on the ASDS thread. The conversion was covered quite well by Helodriver. It all was followed with bated breath and quite hard to miss.

Edit - Wings on deck in Panama Canal
Edit - A Helodriver update
Edit - Another Helodriver update
Edit - And another Helodriver update
Edit - A fourth Helodriver update
Edit - A final Helodriver update

Offline Llian Rhydderch

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There has been quite a lot of previous discussion on this thread that say robotic vessels, whether telerobotic or autonmous, for ships on the seas moving from Port A to Location B to Port C are not possible.

I just tended to believe all the more marine-experienced commentators, figuring they knew more than me.

So was quite surprised to see this today:  Sea Hunter USV Reaches New Autonomy Milestone, where a ship sailed from San Diego to Pearl Harbor, Hawaii, and back with no humans on board.

Does this have implications for the so-called "autonomous" droneships that SpaceX has advanced?  or for their next-generation launch mount for their next-gen rocket?
Re arguments from authority on NSF:  "no one is exempt from error, and errors of authority are usually the worst kind.  Taking your word for things without question is no different than a bracket design not being tested because the designer was an old hand."
"You would actually save yourself time and effort if you were to use evidence and logic to make your points instead of wrapping yourself in the royal mantle of authority.  The approach only works on sheep, not inquisitive, intelligent people."

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