Author Topic: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3  (Read 806967 times)

Offline MarekCyzio

We can assume that one of reasons SpaceX is building automated rocket mounting robot is to reduce time between barge landing and rocket unload (of course main reason is to eliminate potentially very risky task of catching sliding rocket). So it would make sense to perform more processing steps at the barge - at the minimum leg folding. I wonder if this is what SpaceX plans...
 
Edit - typo

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« Last Edit: 02/25/2017 02:12 PM by MarekCyzio »

Offline Alastor

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1781 on: 02/25/2017 03:10 PM »
As far as we understand it right now, the plan would be to grab the rocket by the legs, and we have no indication that they would plan to be able to fold the legs without having to remove them.

The second point may be justified by both safety and processing reasons.
Safety because you don't want risking the legs to fold upon landing. So if they are simply designed to not fold, it's safer. Processing, because I suspect that they at least have to change the crush core everytime, so it may be easier to do with the legs removed.

Now if they grab the rocket by its feet as they seem to be about to do, it would not be possible right now to fole or remove the legs in situ.

I guess a first indication of that happening would be if we see a holding stand and crane appearing on the droneship. So I would say not in the nearfuture at least, and I'm not convinced that it would be really doable.

Offline rpapo

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1782 on: 02/25/2017 03:57 PM »
To have a sufficiently tall crane on the barge, and a stand, I would think the barge would have to get much, much larger.  And trying to manage such a large crane while the barge is pitching and rolling with the waves would be dicey, at best.  So unless SpaceX wants to recycle a full-sized aircraft carrier or an oil super-tanker to recover stages, I would think they're better off simply doing what it appears they are doing: coming up with a safer, more automated way to secure the stage.  There's no pressing need to do more than that, at least that I am aware of.

If they absolutely had to put in something to secure the stage in an upright position and remove the legs before getting back to port, they could always try to do something like the Soyuz TLE in reverse, with multiple arms reaching up from below to enclose the stage like a Venus Flytrap with three or four petals.  Such a Goldberg device would probably be safer than installing a crane on the barge.

It would still require a bigger barge, though, and it probably wouldn't be worth the expense.
« Last Edit: 02/25/2017 03:58 PM by rpapo »
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Online RonM

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1783 on: 02/25/2017 04:09 PM »
Why SpaceX would want to remove the legs at sea? it may save a little time, but it's simpler to hold down the booster by the legs than move it to a mount on the ship.

Offline cscott

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1784 on: 02/25/2017 04:47 PM »
We don't actually "know" that the plan is to grab the feet.  The "Roomba garage" could be for videography drones or fire-fighting robots or who knows what else.
« Last Edit: 02/25/2017 04:52 PM by cscott »

Offline dorkmo

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1785 on: 02/25/2017 06:48 PM »
We don't actually "know" that the plan is to grab the feet.  The "Roomba garage" could be for videography drones or fire-fighting robots or who knows what else.

or just old fashion aircraft jack storage

Offline Alastor

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1786 on: 02/25/2017 07:17 PM »
We don't actually "know" that the plan is to grab the feet.  The "Roomba garage" could be for videography drones or fire-fighting robots or who knows what else.

That's why I used "As far as we understand it", and not "As far as we know".
That said, grabbing it by its feet is quicker, safer and simpler (and thus even safer) that what is currently used.

It makes a lot of sense, and I'm actualy surprised that they didn't use it since the very beginning, since the first landings were arguably the most dangerous ones, given that they were more experimental.

It is the leading theory, there is no indication that they are doing something else, and I am myself fairly certain that's what they are doing, even though I have no definite proof.
Now once that's said, feel free to disagree, but I believe I make a pretty good case ! :-)

Offline Lar

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1787 on: 02/25/2017 09:50 PM »
Why invest in foot welding robots before you know whether there will be any feet to even weld. SpaceX is incremental. Each time, they improve something.

Watch and wait.
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Online Johnnyhinbos

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1788 on: 02/26/2017 01:50 AM »
Okay, so here's my unasked for, un-rooted in firsthand knowledge, prediction.

Based on what the Roadie has alluded, and on what's been shown by the excellent spy photos around the ASDS, and on a general observation of the recovery process, here's my WAG on what's being developed...

Deck ops on the ASDS are dangerous and open SpaceX up for all kinds of liability (my job is to mitigate liability on a relatively dangerous workplace activity, so I'm sensitive to that). So I suggest they're developing a bot (four per ASDS) that has a jack stand top that can autonomously navigate out to under a landed booster, attach to a hold down point and spot weld itself to the deck after a positive capture of the hold down point. Four of these effectively replace the function of the jacks and ratchet chains humans currently need to install under a landed booster. No crane (way too impractical on the barge), no lifting it up into the stands you see in port to remove the legs, and no attaching anything to the legs themselves. The legs are a liability whereas the hold down points on the octoweb are designed to take strain.

This is just to allow an autonomous securing of the stage until its towed to port to take the human out of the loop.

But, as Lar said, time will tell...
« Last Edit: 02/26/2017 01:53 AM by Johnnyhinbos »
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Offline cscott

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1789 on: 02/26/2017 03:41 AM »
How high above the deck are the hold down points?

Offline old_sellsword

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1790 on: 02/26/2017 03:58 AM »
How high above the deck are the hold down points?

About ten feet. It's over five feet from the ground to the bottom of the engine bells, and then I estimated the rest based on this picture.
« Last Edit: 02/26/2017 03:58 AM by old_sellsword »

Offline meekGee

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1791 on: 02/26/2017 06:11 AM »
Okay, so here's my unasked for, un-rooted in firsthand knowledge, prediction.

Based on what the Roadie has alluded, and on what's been shown by the excellent spy photos around the ASDS, and on a general observation of the recovery process, here's my WAG on what's being developed...

Deck ops on the ASDS are dangerous and open SpaceX up for all kinds of liability (my job is to mitigate liability on a relatively dangerous workplace activity, so I'm sensitive to that). So I suggest they're developing a bot (four per ASDS) that has a jack stand top that can autonomously navigate out to under a landed booster, attach to a hold down point and spot weld itself to the deck after a positive capture of the hold down point. Four of these effectively replace the function of the jacks and ratchet chains humans currently need to install under a landed booster. No crane (way too impractical on the barge), no lifting it up into the stands you see in port to remove the legs, and no attaching anything to the legs themselves. The legs are a liability whereas the hold down points on the octoweb are designed to take strain.

This is just to allow an autonomous securing of the stage until its towed to port to take the human out of the loop.

But, as Lar said, time will tell...

If you're right, and the intent is to catch the thrust structure (or hold-downs) then you need a single large robot (3.7m diameter) since everything is rigid.  It drives underneath, grabs the holddowns, and welds itself down.  I like that a lot.

However, I'm voting for "catch it be the legs" until the crew can board.  That'll be a plenty safe condition for them to operate on the rocket. Since the legs are not rigid, (and since you won't build a 20m robot) then in that case I'd vote for 4 individual robots.

I'll be happy either way, assuming always we are talking about a tie-down robot of some sort.

(And I 100% agree with the rationale.  Boarding a barge with an unsecured load like this is just waiting for an accident)
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Offline marksmit

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1792 on: 02/26/2017 09:54 AM »
A whole bunch of high quality new photos of OCISLY of yesterday: https://imgur.com/gallery/TDVSV
« Last Edit: 02/26/2017 09:56 AM by marksmit »

Offline Herb Schaltegger

Excellent photos. Looks like they've built a small platform area between the top of the existing blast deflector and the newly-elevated equipment container, and built a new section of blast deflector plates on that elevated platform to protect the exposed top half of the container. Whatever is going into the "garage area" below the new platform and container behind the existing blast wall will be pretty well protected.

Still not convinced it's going to be  "Roomba welders" or any such Rube Goldberg contraption, but it will be interesting to watch.
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Offline meekGee

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1794 on: 02/26/2017 03:11 PM »
Excellent photos. Looks like they've built a small platform area between the top of the existing blast deflector and the newly-elevated equipment container, and built a new section of blast deflector plates on that elevated platform to protect the exposed top half of the container. Whatever is going into the "garage area" below the new platform and container behind the existing blast wall will be pretty well protected.

Still not convinced it's going to be  "Roomba welders" or any such Rube Goldberg contraption, but it will be interesting to watch.
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Online matthewkantar

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1795 on: 02/26/2017 05:27 PM »
They had a little man lift on board for early landing attempts but it got toasted in a crash. I don't think they have had one aboard since. Not sure what they were planning on using the rig for, but It seems likely the purpose of the new garage is to protect it. Weldbas would be cool though.

Matthew

Offline MarekCyzio

Garage is ready

Offline vanoord

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1797 on: 02/26/2017 07:15 PM »
There are several big welded-on eyes / attachment points on both the refitted section of blast wall and the flat deck above it.  I wonder what they're for?

Looking at that image, it might just be that they want to store something like decent-sized welding sets on board and be able to lift up a section of blast wall and roll them out.

We sometimes look for complication, forgetting that a lot of what SpaceX does is simple (admittedly well-executed) rather than intricate to the extreme.

Offline Davp99

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1798 on: 02/26/2017 07:26 PM »
Aye Skipper, Open up the "Shamrock Garage"..
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Offline CJ

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #1799 on: 02/26/2017 07:50 PM »
After a look at the pics (Thanks!!!!!!!!), I now agree with those who say something is definitely going on regarding the blast wall and that new space under a container.

I'm dubious that they are making the blast wall open upward though; that would be hard due to the weight of it. My guess is either sliding to the side, or hinged panels opening outward.

My current prime suspect for a resident of the new space is a cherry picker, but that's just a wild guess. 

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