Author Topic: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3  (Read 815425 times)

Offline manoweb

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2100 on: 10/13/2017 05:52 PM »
Hello, I just read the "octograbber" has already been used. Which thread covers it? I could not easily find it

Offline old_sellsword

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2101 on: 10/13/2017 05:56 PM »
Hello, I just read the "octograbber" has already been used. Which thread covers it? I could not easily find it

Here:

Quote
Michael Seeley‏ @Mike_Seeley 1m1 minute ago

Welcome home, #Falcon9. The now twice launched & landed #SpaceX #BulgariaSat1 just returned to port aboard the #OCISLY.  – at Jetty Park Pier

https://twitter.com/Mike_Seeley/status/880407593042182144

Yep, looks like a Roomba!  8)

Offline Geron

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2102 on: 10/13/2017 06:13 PM »
Looks like that rocket came in "hot". Hotter than usual as those gridfins are super toasted!!

Offline cscott

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2103 on: 10/14/2017 08:14 AM »
From the other thread, BulgariaSat's speed after the re-entry burn was about 600km/h faster than SES-11:

I was really amazed to see that it was showing 6,000 km/h when the entry burn ended, is that a record?

During BulgariaSat-1 launch 1st stage was traveling at 6600km/h hen the entry burn ended.

« Last Edit: 10/14/2017 08:19 AM by cscott »

Offline Herb Schaltegger

Interesting video shared to the SpaceX Facebook group regarding the return of the SES-11 booster. She's leaning a bit. Roomba garage is open but you can't see if it's being used or not.

https://www.facebook.com/groups/spacexgroup/permalink/10155923362006318/
« Last Edit: 10/14/2017 04:21 PM by Herb Schaltegger »
Ad astra per aspirin ...

Offline southshore26

Interesting video shared to the SpaceX Facebook group regarding the return of the SES-11 booster. She's leaning a bit. Roomba garage is open but you can't see if it's being used or not.

https://www.facebook.com/groups/spacexgroup/permalink/10155923362006318/

Not used... what’s left of it was still inside or just out front of the garage... hard to tell from the angle I was at.

Offline vanoord

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2106 on: 10/18/2017 08:27 AM »
https://twitter.com/EmreKelly/status/920398227521855490

From looking at the above photograph, three, possibly four containers appear to have been removed from the aft (?) / Octagrabber end of OCISLY - presumably at least one contains the equipment that powers the Thrustmaster pod.

Compare and contrast with this slightly earlier photograph:

https://twitter.com/julia_bergeron/status/920042069594435585

The container that was above the Octagrabber's garage is on the deck at the far end of OCISLY, but has now been lifted off entirely.

Working in reverse chronological order, a lightly earlier photo with all the containers in place:

https://twitter.com/Restrantek/status/920232647909105664

Offline woods170

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2107 on: 10/18/2017 11:37 AM »
https://twitter.com/EmreKelly/status/920398227521855490

From looking at the above photograph, three, possibly four containers appear to have been removed from the aft (?) / Octagrabber end of OCISLY - presumably at least one contains the equipment that powers the Thrustmaster pod.

Compare and contrast with this slightly earlier photograph:

https://twitter.com/julia_bergeron/status/920042069594435585

The container that was above the Octagrabber's garage is on the deck at the far end of OCISLY, but has now been lifted off entirely.

Working in reverse chronological order, a lightly earlier photo with all the containers in place:

https://twitter.com/Restrantek/status/920232647909105664

Also note, in the first image, that with the removal of several containers, that particular end of OCISLY is now floating high in the water.

Offline Alastor

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2108 on: 10/18/2017 12:05 PM »
Also note, in the first image, that with the removal of several containers, that particular end of OCISLY is now floating high in the water.
They probably have had to detank all fuel reserves for that thruster on that side, too, so there's a lot of mass gone.

Offline vanoord

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2109 on: 10/18/2017 12:36 PM »
Also note, in the first image, that with the removal of several containers, that particular end of OCISLY is now floating high in the water.
They probably have had to detank all fuel reserves for that thruster on that side, too, so there's a lot of mass gone.

I saw that and didn't reckon it was down to the weight of the containers alone. I wouldn't be surprised if - for whatever reason - ballast water has been pumped out at that end (/ in at the other end.

Offline CameronD

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2110 on: 10/18/2017 11:12 PM »
Also note, in the first image, that with the removal of several containers, that particular end of OCISLY is now floating high in the water.
They probably have had to detank all fuel reserves for that thruster on that side, too, so there's a lot of mass gone.

I saw that and didn't reckon it was down to the weight of the containers alone. I wouldn't be surprised if - for whatever reason - ballast water has been pumped out at that end (/ in at the other end.

It'll just be the containers.  Keeping ballast (sea) water on board a steel-hulled vessel for no particular reason is a really bad idea, although it's possible they didn't pump the fire (fresh) water out after the last landing and that's making the tilt look worse.
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 vanoord

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2111 on: 10/19/2017 09:00 AM »
Back of an envelope calculation, with the help of - http://www.mcdonoughmarine.com/assets/mcd-spec-sheets_v8-marmac_304.pdf

The barge is 300' x 100', so 91m x 30m

Because the bow and stern of the barge are raked, roughly assume that removes the buoyancy from 10m either end, so work off 70m useful length.

Using the rubbing strakes on the side as a guide, that end is a bit over 1m out of the water more than usual (it's probably more like 4ft, but I'd prefer to under-estimate).

(The fouling of the underwater area suggests she usually draws between 11ft and 12ft).

She's only floating high at the one end, so the additional volume out of the water compared to usual should be:

Length x beam x reduced depth x 0.5 (ie it tapers to nil over the length of the barge)
70m x 30m x 1m x0.5 =1,050m³

Rounding this down a bit, that's about 1,000 metric tons off the displacement - and that's not down to equipment, fuel: they've pumped ballast water out to bring that end out of the water for whatever reason.


From the data sheet, the cargo capacity for Marmac 304 / OCISLY is quoted at 11,318 Short Tons / 10,267 metric tons (this surprised me) - the weight of the containers etc. is going to make virtually no difference to the trim of the barge.

Offline Alastor

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2112 on: 10/19/2017 09:52 AM »
Rounding this down a bit, that's about 1,000 metric tons off the displacement - and that's not down to equipment, fuel: they've pumped ballast water out to bring that end out of the water for whatever reason.

Great envelope usage !

So they're probably performing inspection duty or even repairs.
The last time we've seen them do such a thing IIRC is to patch the hole when an F9 kinda punched through.

It's entirely possible that the fuel tanks in that side of the barge (I assume them to be located under deck, correct ?) were damaged by the fire. If so, there might have be a fire under the deck too, and possibly much worse than up there. At the very least, they'll have to inspect that side for fire damage and maybe they'll have to replace some hull plates or some structure beams.

Edit : Apparently the fuel storage is on deck and there can only be water bellow deck.
« Last Edit: 10/20/2017 08:59 AM by Alastor »

Offline abaddon

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2113 on: 10/19/2017 02:00 PM »
Interesting video shared to the SpaceX Facebook group regarding the return of the SES-11 booster. She's leaning a bit. Roomba garage is open but you can't see if it's being used or not.

https://www.facebook.com/groups/spacexgroup/permalink/10155923362006318/
The post has been edited to say
Quote
Edit: per below this is Bulgariasat 1 (1029.2) not SES-11(1031.2)

Offline CameronD

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2114 on: 10/20/2017 12:08 AM »
Using the rubbing strakes on the side as a guide, that end is a bit over 1m out of the water more than usual (it's probably more like 4ft, but I'd prefer to under-estimate).

Allow me to disagree, but I REALLY don't see how you can say that.  The photo referred to (a) has been taken from a significant distance and (b) has been taken at an angle (which would over-emphasize any tilt) so I'd be waiting for a high-res side-on shot before jumping to too many conclusions..

Besides, the specs you linked to give barge height to be roughly 20'.  If usual draft is 11' as you say, that means only 9' (~3m) freeboard under normal conditions.   Because it's floating, trimming high at one end means it'll be sitting (slightly) lower in the water at the other end making it look worse than it really is.
« Last Edit: 10/20/2017 12:13 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 CameronD

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2115 on: 10/20/2017 12:11 AM »
It's entirely possible that the fuel tanks in that side of the barge (I assume them to be located under deck, correct ?) were damaged by the fire. If so, there might have be a fire under the deck too, and possibly much worse than up there. At the very least, they'll have to inspect that side for fire damage and maybe they'll have to replace some hull plates or some structure beams.

We know from previous posts in this thread that diesel fuel for the thrusters is stored in large rectangular self-bunded tanks on deck.  The only thing they are allowed to store below deck is water.
« Last Edit: 10/20/2017 01:44 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 Alastor

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2116 on: 10/20/2017 08:58 AM »
It's entirely possible that the fuel tanks in that side of the barge (I assume them to be located under deck, correct ?) were damaged by the fire. If so, there might have be a fire under the deck too, and possibly much worse than up there. At the very least, they'll have to inspect that side for fire damage and maybe they'll have to replace some hull plates or some structure beams.

We know from previous posts in this thread that diesel fuel for the thrusters is stored in large rectangular self-bunded tanks on deck.  The only thing they are allowed to store below deck is water.

Oh, thanks, I missed that information ! I corrected my previous post to reflect it.
No fire bellow deck then. Still, my bet is on inspection/repairs.  ;D

Offline vanoord

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2117 on: 10/20/2017 08:59 AM »
Allow me to disagree, but I REALLY don't see how you can say that.  The photo referred to (a) has been taken from a significant distance and (b) has been taken at an angle (which would over-emphasize any tilt) so I'd be waiting for a high-res side-on shot before jumping to too many conclusions..

Besides, the specs you linked to give barge height to be roughly 20'.  If usual draft is 11' as you say, that means only 9' (~3m) freeboard under normal conditions.   Because it's floating, trimming high at one end means it'll be sitting (slightly) lower in the water at the other end making it look worse than it really is.

Trimming one end by moving the ballast to the other end would make the other end sit deeper in the water and from the look of the fouling line, the other end (the bow) is floating at about the right height.

A photograph won't distort vertical distance over such short distances as we're looking at: see the attached quick sketch which shows - if I may be so bold! - that the stern of the barge is *at least* aft / 1m more out of the water than usual. (The rubbing strakes are a known 6ft apart, taken from the barge owner's drawing).

Whatever the numbers, the difference in height is down to more than just the removal of the containers ;)

Offline vanoord

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2118 on: 10/23/2017 06:56 PM »
A few photos of OCISLY from last Thursday by user 'pin2hot' on Reddit:

https://imgur.com/a/CwL5w :o

Offline vanoord

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2119 on: 10/26/2017 09:47 AM »
Fleet update, according to MarineTraffic.

The 'new' tug Hawk is alongside OCISLY's usual berth, along with Go Quest - suggesting they are preparing to depart in the next couple of days.

Elsbeth III is upriver from Jacksonville, in the same place that the Go 'twins' sheltered from Hurricane Irma - so it looks like Hawk has got the OCISLY gig for KoreaSat.

The surprise is Go Searcher - which was last noted off the Cuban coast four days ago, heading for Puerto Rico.

Conceivably if she was being used to deliver something there, she could probably meet up with the rest of the fleet offshore sometime around launch day but otherwise there doesn't seem to be anything at Port Canaveral at the moment which is of a similar type - but no reason to rule out something being borrowed from elsewhere if Go Searcher doesn't return in time.

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