Author Topic: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3  (Read 791438 times)

Online meekGee

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #360 on: 04/04/2016 08:19 PM »
I really don't get the TNT analogy.

All we've seen so far are "soft" conflagrations, and the shock from the bursting pressure vessel.

If the rocket is falling at at some 200 m/s, and it's a 40 m stage, and it never slows down even after starting to crumple, that's still 1/5 of a second for "mix and burn" time. (a.k.a pancaking time) This is an eternity in terms of explosions.

With the rocket slowing down once the concentrated mass hits the deck, it's probably closer to 0.5 second.

If you ignore the LOX and only consider the RP1 being kicked out into the atmosphere, then most definitely you get a slow burn.  This is why fuel-air bomb have to mix first, burn later. in order to get a real explosion.

And 500 lb of TNT....   detonated in contact with the deck...   I think you'd get a bigger hole...

Almost without a doubt the hole was made by punching through, and the following fire ball did almost nothing, though potentially if fuel managed to get into the hole, it may have burned there for a while.
« Last Edit: 04/04/2016 08:22 PM by meekGee »
ABCD - Always Be Counting Down

Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #361 on: 04/04/2016 08:22 PM »
Quote
If you ignore the LOX and only consider the RP1 being kicked out into the atmosphere, then most definitely you get a slow burn.  This is why fuel-air bomb have to mix first, burn later. in order to get a real explosion.

And 500 lb of TNT....   detonated in contact with the deck...   I think you'd get a bigger hole...

Yes, for ease of calculation they probably assumed a limiting case of fully-mixed LOX/RP-1, knowing you'd never really get there.

It seems the real purpose of the TNT equivalent calculation was to be able to predict the maximum projectile distance of 1250 ft, probably from a look-up table or graph of max distance vs quantity of TNT.

Obviously if you put 500 lbs of TNT on deck, the *local* blast effect would be much different...
« Last Edit: 04/04/2016 08:49 PM by Kabloona »

Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #362 on: 04/04/2016 08:31 PM »
Anyone want to estimate the time remaining for fixes and repairs to be on station and ready for a Friday launch?

They'll need a little over 30 hours transit time, plus setup time on station. I'd say sometime late Wednesday is the comfortable deadline for departure, and possibly wee hours of Thursday morning if they have to cut it really close.
« Last Edit: 04/04/2016 08:36 PM by Kabloona »

Offline OxCartMark

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #363 on: 04/04/2016 09:03 PM »
I'm not used to reading these type statements but the few that I've come across on NSF seem to be not so much science as they are arguments for what the writer wants to do written in sciencey language as a tool of persuasion.

Offline Hywel1995

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #364 on: 04/04/2016 10:00 PM »
Matthew Travis on Facebook is reporting activity from the support ships around the ASDS. Might be preparing to leave under the darkness.

Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #365 on: 04/04/2016 10:21 PM »
Matthew Travis on Facebook is reporting activity from the support ships around the ASDS. Might be preparing to leave under the darkness.

It's too soon to be heading out to the landing zone tonight. They may just be moving the support ships back over from the Fishlips side of the port.
« Last Edit: 04/04/2016 10:22 PM by Kabloona »

Offline OxCartMark

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #366 on: 04/05/2016 12:18 AM »
Or a near shore test run tomorrow.

Offline thor1872

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #367 on: 04/05/2016 12:27 AM »
« Last Edit: 04/05/2016 03:05 AM by thor1872 »

Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #368 on: 04/05/2016 01:44 AM »
Or a near shore test run tomorrow.

And they don't have to leave until after static fire, so if there's a problem with static fire that causes a launch slip, the armada can hang back in port an extra day or two instead of waiting around in the middle of the ocean like they had to do last time. So another reason not to leave until Wednesday at earliest.

Offline MarekCyzio

Two panoramas from yesterday around 6:30 PM. No activity - either they are done with all repairs, or they are not going to use ASDS for CRS-8.

Offline MarekCyzio

And GoQuest with opened containers
« Last Edit: 04/05/2016 12:18 PM by MarekCyzio »

Offline Retired Downrange

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #371 on: 04/05/2016 01:15 PM »
In the photo of OCISLY it appears that one of the thrusters is removed.

[edit] ...as eriblo points out in next post, I can see the lower unit of the thruster down at water level, my confusion stems from the fact that the view of the vertical shaft is hidden.... I didn't recall this from previous photos.
« Last Edit: 04/05/2016 02:39 PM by Retired Downrange »

Offline eriblo

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #372 on: 04/05/2016 01:21 PM »
In the photo of OCISLY it appears that one of the thrusters is removed.
Which one? I believe I can see the three that should be visible - the one to the left is deployed all the way down (look beneath the mount).
« Last Edit: 04/05/2016 01:23 PM by eriblo »

Offline matthewkantar

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #373 on: 04/05/2016 02:17 PM »
Looks like all of the welding and cutting gear is off the deck, probably ready or nearly ready to hit the open sea.

Matthew

Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #374 on: 04/05/2016 02:46 PM »
Or a near shore test run tomorrow.

Bingo. EIII headed over to OCISLY early this morning, then left port, now heading ESE (not towards landing zone). Probably towing OCISLY for test run. Port webcam shows OCISLY berth empty.

Edit: but I will add that the ESE course is following the channel leaving Port Canaveral, so they could later turn northeast toward the landing zone and head there directly. I would have thought they would wait until after stagic fire for departure, but it's *possible* this is the real thing and not just a test run, though they would get there way early.
« Last Edit: 04/05/2016 03:56 PM by Kabloona »

Offline Blizzzard

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #375 on: 04/05/2016 03:13 PM »
If they are going for a test run, and are also cutting it fine for leaving for landing site - could they test then go straight out to the landing site from there?

Offline cscott

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #376 on: 04/05/2016 03:17 PM »
I'd expect them to wait until the static fire is complete (later today, hopefully) before leaving for the landing site.

Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #377 on: 04/05/2016 04:00 PM »
Someone caught departure on camera:

https://www.instagram.com/p/BD0pGX8BRj2/

Offline thor1872

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #378 on: 04/05/2016 05:04 PM »

Offline chrisking0997

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #379 on: 04/05/2016 05:34 PM »
looks like they cleaned up the shamrock before leaving
Tried to tell you, we did.  Listen, you did not.  Now, screwed we all are.

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