Author Topic: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3  (Read 527803 times)

Online JamesH65

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2020 on: 06/28/2017 10:13 AM »
Interesting that John Insprucker mentioned on the Iridium launch webcast that the ASDS does *not* send any signals to the returning stage; it only receives telemetry from the stage.

We have known this pretty much from the beginning, but some people were skeptical, so it's worth noting that we now have confirmation of the fact directly from SpaceX.

Corollary. Why does the ASDS need to receive telemetry from the stage? It knows it's on its way, it doesn't need to move, it doesn't need to know anything.
In this case, the ASDS serves as a data relay for SpaceX, since by the time the stage is closing in on the ASDS, it is below the horizon from the launch pad.

Unless I'm much mistaken, it's one of the support ships that performs the data relay function - not the ASDS - since, as you quite rightly mentioned, it is below the horizon from the launch pad.

We know this because, long ago, in a thread not far away from this one, a knowledgeable and determined NSFer (not me!) sorted through the on-line list of SpaceX's FCC RF licence approvals and worked out what was being sent by what to where.  Very impressive it was too!!

Anyways, since it's a proven point already, let's move on shall we?

Er, what is proven? You've just said that the data relay is via another ship, not the ASDS,so why does the stage send data to the ASDS if it isn't the relay?

Offline leetdan

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2021 on: 06/28/2017 12:39 PM »
The callout specifically says the Drone Ship has AOS, as opposed to the support ship.  The ASDS is in a relatively fixed position relative to the returning stage.  The support ship would be moving closer and closer to the horizon, possibly out of LOS completely depending on sea state.

There was already going to be a data link from ASDS to support ship if they wanted live landing video, there's no reason the telemetry wouldn't use this same link.

Offline mme

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2022 on: 06/28/2017 03:39 PM »
Interesting that John Insprucker mentioned on the Iridium launch webcast that the ASDS does *not* send any signals to the returning stage; it only receives telemetry from the stage.
...
His exact words were "The drone ship does not send commands to the first stage in flight."  That leaves open whether or not commands are given to the stage after it lands, perhaps as part of safing it.  I'm not sure why that would be necessary though: the safing process could and probably should be entirely automatic.  After all, the rocket knows when it has landed.

Evidence of some sort of communication from the ASDS after the stage has landed. So maybe related to safing:

...
First Stage Recovery permit application:
Quote
This STA covers the experimental first-stage recovery operation, following a Falcon 9 launch from Vandenberg Air Force Base. This request is limited to the brief command uplink from an autonomous droneship to the launch vehicle after landing.
Ship Coordinates: North 31 39 58   West 121 39 43
Space is not Highlander.  There can, and will, be more than one.

Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2023 on: 06/28/2017 03:57 PM »
From the bits of information we have, seems to me this is the likely state of data relays:

Stage 1 telemetry/video is received directly by support ship and uplinked to land via its onboard VSAT
"                       "  also received by ASDS (known from "drone ship AOS" callout)

ASDS uplinks its own telemetry/video back to land via its onboard VSAT (interrupted by vibe during landing)
ASDS sends stage safing commands after landing

Offline RDMM2081

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2024 on: 07/03/2017 07:53 AM »
Sorry if I missed it in this mass of ASDS threads, but has there been any attempt made at an estimate of total cost of ASDS, barge + materials + thrusters + avionics + paint etc. I.E. what might SpaceX insure them for (assuming they could get insurance for something they are actively targeting with multiple tons of incoming ballistic "missile") or what might it cost them to replace from the ground up?

I think when they were first announced (ASDS in general) I made a super rough estimate of $3m for a Marmac, $1m for the steel deck plating, $500k for the thrusters, and another $500k for labor, paint and fuel, plus $250k for towing for the first landing attempt mission. 

Anyone else have any guesses or adjustments?

Since each ASDS has caught one stage... that later has reflown... (two reflown to date)
I think we can safely say that both are nearing cash positive on the Spacex books... all in...  ;)

IOW... Cost to build and maintain both ASDS's... Costs ongoing for two tugs on call and three Go boats on call...
Cost to refurb the stages... Cost of cranes... Cost of port leases and installed fixturing... Cost of labor...

Balance that against not having to build two stages so far... My opinion is close to break even as of today...
Refly another stage and it starts going against the other costs to date company wide...

Just my opinion on question posed...  ;)

Thanks for the response and input :). Sounds like we have some fairly different assumptions about the costs of the ASDS program, but also I think I can safely see my way to get into your ballpark of costs, especially adding in all the support ship costs I think I overlooked in my first ballpark estimate(guess). 

When you start phrasing it in terms of cost saved per booster recovered and reflown(catching a stack of cash about $30m high?) it's pretty hard to imagine that the cost of the entire program over its lifetime isn't at least very close to break-even, and with most of the investment already made it should start returning value rather well going forward.

Thanks again for taking a moment to think about it and respond!

Offline nickninevah

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2025 on: 07/31/2017 10:45 PM »
Professional ship designer here.  I work with barges like the ASDS all the time.

Daily rates for an ocean-going tug are an average of $15k / day / tug. 

http://www.marcon.com/library/articles/2007/Tug%20Trends%20-%20Final%20color.pdf

If you assume a distance of 120 NM offshore, then you get around 5-6 days time for each launch.  So tug commitment is $90k / tug / launch. 

Docking fees are around $0.45 / GRT.  For the ASDS, that comes to around $60k / month.

Barge costs around $10M to build and equip with the thrustmaster DP modules.

Add in some $20k/launch for fuel and supplies.  And another $10k/launch for cranes. 

Including a rough insurance cost.  Assume 1 launch per month and assume that you own the barge (because I don't want to consider charter rates in the 10 minutes I spent on this).  And assume a 10 year operational life, which is really short for a barge.  That gives you a capitalized cost of around $38M for 10 years of barge operations.  (roughly $317k per launch.)

If you do two launches per month, that gives you a capitalized cost of around $60M for 10 years. (roughly $250k per launch.)  Someone else said a new Falcon 9 costs $30M?  My estimates don't include costs of making the rocket ready for the next launch.  But still safe to say a good value proposition.


Offline CameronD

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2026 on: 07/31/2017 11:46 PM »
Professional ship designer here.  I work with barges like the ASDS all the time.

Daily rates for an ocean-going tug are an average of $15k / day / tug. 

http://www.marcon.com/library/articles/2007/Tug%20Trends%20-%20Final%20color.pdf

If you assume a distance of 120 NM offshore, then you get around 5-6 days time for each launch.  So tug commitment is $90k / tug / launch. 

Docking fees are around $0.45 / GRT.  For the ASDS, that comes to around $60k / month.

Barge costs around $10M to build and equip with the thrustmaster DP modules.

Add in some $20k/launch for fuel and supplies.  And another $10k/launch for cranes. 

Including a rough insurance cost.  Assume 1 launch per month and assume that you own the barge (because I don't want to consider charter rates in the 10 minutes I spent on this).  And assume a 10 year operational life, which is really short for a barge.  That gives you a capitalized cost of around $38M for 10 years of barge operations.  (roughly $317k per launch.)

If you do two launches per month, that gives you a capitalized cost of around $60M for 10 years. (roughly $250k per launch.)  Someone else said a new Falcon 9 costs $30M?  My estimates don't include costs of making the rocket ready for the next launch.  But still safe to say a good value proposition.

Thanks for your input and info on this... and welcome to the forum! :)

My only comment is that, in this case, SpaceX have chosen to charter the barges.  That seemed to make sense initially because it was very much an experiment, but now maybe not so much?

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 nickninevah

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2027 on: 08/01/2017 04:35 PM »
My only comment is that, in this case, SpaceX have chosen to charter the barges.  That seemed to make sense initially because it was very much an experiment, but now maybe not so much?


Fair point.  As you said, it makes sense to charter when this is just an initial experiment.  I initially avoided the charter question because it gets really complicated.  Each charter contract is different depending on who pays for what (insurance, regulatory fees, crew costs, fuel, etc).  But to take my already rough numbers and make them even more rough:

That barge is a standard ocean going deck barge.  Almost as simple as it gets.  So assume a low charter rate of $5k per day.  Then add in $1M to outfit the barge as a drone ship.  And add another $1M to put it back the way you found it when you are done.  Over 10 years, the capitalized cost for a chartered barge, with mods, is somewhere around $17.6M.  (+/- 50%)

Doing one launch per month, that works out to a total capital cost of about $45.5M, or $380k per launch.
Doing two launches per month, you get a total capital cost of about $67.6M, or $282k per launch.

So the cost of chartering is not much greater than owning the vessel.  And you can negotiate the charter contract so that the marine company handles all the hassles of owning a vessel. 

The one downside is that you don't get to customize the vessel in any important way.  If I wanted to land a rocket on an ocean barge, I think my first priority is a stable platform with minimal motions. 

A barge is almost the worst type of vessel for that purpose.  Barges are extremely sensitive to ocean waves, even if you add ballast.  So that severely limits the ocean weather that you can recover in.

I saw some other forum postings about creating 6DOF active motion compensating platform on the ASDS.  With the right vessel, you don't need any of that.  We can use combinations of trimaran hulls to make them less sensitive to ocean waves.  Then add in heave plates.  Those severely dampen out the vessel motions and act as a great sea anchor.  That's already 75% of the vessel motions gone, without a single active system.

Then there is the position control system.  The Thrustmaster units are great if you want something to drop onto a barge.  But there are other vendors with better integrated units.  The offshore oil industry has refined position control to an artform with their semi submersible drilling rigs.  I have even seen specialized propeller units that can both keep position, and compensate for vessel roll motions at the same time (3 DOF control:  surge, sway, and roll).

So yeah, I like the current ASDS.  But I really want to know what the next generation looks like.

Online Johnnyhinbos

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2028 on: 08/02/2017 03:03 AM »
I think something like this...
John Hanzl. Author, action / adventure www.johnhanzl.com

Offline mme

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2029 on: 08/02/2017 05:59 AM »
My only comment is that, in this case, SpaceX have chosen to charter the barges.  That seemed to make sense initially because it was very much an experiment, but now maybe not so much?


Fair point.  As you said, it makes sense to charter when this is just an initial experiment.  I initially avoided the charter question because it gets really complicated.  Each charter contract is different depending on who pays for what (insurance, regulatory fees, crew costs, fuel, etc).  But to take my already rough numbers and make them even more rough:

...

So yeah, I like the current ASDS.  But I really want to know what the next generation looks like.
I think SpaceX's plan is that there is no next generation ASDS.  I think the point to ITSy is that the booster can always RTLS.  Presumably the reusable second stage will be able to choose when it deorbits so it lands on land as well.
Space is not Highlander.  There can, and will, be more than one.

Offline Comga

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2030 on: 08/03/2017 04:32 AM »
I think SpaceX's plan is that there is no next generation ASDS.  I think the point to ITSy is that the booster can always RTLS.  Presumably the reusable second stage will be able to choose when it deorbits so it lands on land as well.

Their plan was to always RTLC (Return To Launch Cradle ;) ) but that was just a plan.

We haven't seen much evidence of progress to that end, like we saw Grasshopper pathfinding for vertical landing. It's a grand vision, but all the physical evidence we have seen is a ginormous composite tank, which was tested to destruction, and a small methalox engine doing short bursts.  There will be changes in implementation.

Maybe they would put a landing cradle on one of the ASDSs.

 
« Last Edit: 08/03/2017 04:32 AM by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Alastor

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2031 on: 08/03/2017 12:12 PM »
I think SpaceX's plan is that there is no next generation ASDS.  I think the point to ITSy is that the booster can always RTLS.  Presumably the reusable second stage will be able to choose when it deorbits so it lands on land as well.

Their plan was to always RTLC (Return To Launch Cradle ;) ) but that was just a plan.

We haven't seen much evidence of progress to that end, like we saw Grasshopper pathfinding for vertical landing. It's a grand vision, but all the physical evidence we have seen is a ginormous composite tank, which was tested to destruction, and a small methalox engine doing short bursts.  There will be changes in implementation.

Maybe they would put a landing cradle on one of the ASDSs.

 

If they are to ever use the landing on the launch craddle, it is clear to me that they will have to test it first on something that can be destroyed in case of failiure without destroying the launchpad.
Maybe it can however be a hybrid between a landing cradle and the landing legs so that the stage doesn't get destroyed if the craddle fails or if the landing isn't accurate enough, initially ?

I guess we'll have to see, but clearly, with a big rocket like that, there is an incentive to try not to loose the stage while testing, so at the very least, we can expectan initial period with landing legs while figuring out how to land accurately and reproducibly enough with these new stages.
First stage can probably RTLS early in the development cycle, since they have a lot of experience with landing first stages by now.
I would expect 2nd stage to initially go for an ASDS landing until it is prooved that they can land the 2nd stage with a good enough level of confidence.

I wouldn't expect to see development of a landing craddle before both stages can RTLS, since rapid relaunch will come after rapid reusability in their priority tree.

But anyway, back to our regular programming. How are our ASDSs doing recently ? Haven't heard much about them  in a while !

Offline kaiser

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2032 on: 08/09/2017 07:24 PM »
My only comment is that, in this case, SpaceX have chosen to charter the barges.  That seemed to make sense initially because it was very much an experiment, but now maybe not so much?


Fair point.  As you said, it makes sense to charter when this is just an initial experiment.  I initially avoided the charter question because it gets really complicated.  Each charter contract is different depending on who pays for what (insurance, regulatory fees, crew costs, fuel, etc).  But to take my already rough numbers and make them even more rough:

That barge is a standard ocean going deck barge.  Almost as simple as it gets.  So assume a low charter rate of $5k per day.

$5k per day is ridiculously low for ANY boat charter, much less one the size on an ASDS.  The ASDS likely burns $5k per day in fuel.  The boat I charter to go out to sea (~150' long, not very wide and not very fast) costs $4k per day in fuel. Add in depreciation costs, registration costs, insurance, remote monitoring staff, satcom costs, etc, etc. and you're into 5 digits pretty quickly.
« Last Edit: 08/09/2017 07:25 PM by kaiser »

Offline gongora

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2033 on: 08/09/2017 07:31 PM »
My only comment is that, in this case, SpaceX have chosen to charter the barges.  That seemed to make sense initially because it was very much an experiment, but now maybe not so much?


Fair point.  As you said, it makes sense to charter when this is just an initial experiment.  I initially avoided the charter question because it gets really complicated.  Each charter contract is different depending on who pays for what (insurance, regulatory fees, crew costs, fuel, etc).  But to take my already rough numbers and make them even more rough:

That barge is a standard ocean going deck barge.  Almost as simple as it gets.  So assume a low charter rate of $5k per day.

$5k per day is ridiculously low for ANY boat charter, much less one the size on an ASDS.  The ASDS likely burns $5k per day in fuel.  The boat I charter to go out to sea (~150' long, not very wide and not very fast) costs $4k per day in fuel. Add in depreciation costs, registration costs, insurance, remote monitoring staff, satcom costs, etc, etc. and you're into 5 digits pretty quickly.

He listed the barge and the tug separately.  The $5k was just for a barge that can be turned into an ASDS.

Offline Lar

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2034 on: 08/09/2017 08:13 PM »
He listed the barge and the tug separately.  The $5k was just for a barge that can be turned into an ASDS.

The ASDS thrusters use fuel but a) not all the time, only on the days they are keeping station and b) that probably is accounted for elsewhere in the estimate, since the barge leasing company did not supply the thrusters, SpaceX installed them...

tl/dr: I agree. :)
« Last Edit: 08/09/2017 08:13 PM by Lar »
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline cscott

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2035 on: 08/10/2017 04:35 PM »
I believe we've seen the support ships leave port to do non-spacex-related work.  So they might not be 100% under contract.

Offline southshore26

I believe we've seen the support ships leave port to do non-spacex-related work.  So they might not be 100% under contract.

E3 maybe.... but the Go Twins have SpaceX specific gear that stays on their decks. I have yet to see them leave port for any length of time that wasn't SX related.

Offline cscott

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2037 on: 08/10/2017 04:40 PM »
Yeah, it was E3 I was mostly referring to.

Offline southshore26

Yeah, it was E3 I was mostly referring to.

Possible but not likely. Except for one trip where I believe she had some work done to the ship, I haven't seen her leave in 2 years without OCISLY in tow. I follow her on the web monitoring site so I get a notification when she leaves port.

Offline cscott

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #2039 on: 08/11/2017 07:33 AM »
There was also that trip alone to Florida, where the speculation was she was testing radio gear.

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