Author Topic: SpaceX Texas launch site Discussion and Updates - Thread 6  (Read 478572 times)

Offline Jcc

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #580 on: 12/23/2017 09:10 PM »
I don't know if it's feasible to pipe liquified L2 and CH4 across 5 miles of ocean, but certainly it could be piped in gasseous form and liquified there. So perhaps a separate but nearby platform for liquification/densification, with tanks. Delivering liquified propellant by boat would be less convenient. Maybe liquified propellants can be delivered by pipe, but it just seems difficult to me to keep it cold enough going that distance.

Offline Lar

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #581 on: 12/23/2017 09:16 PM »
I don't know if it's feasible to pipe liquified L2 and CH4 across 5 miles of ocean, but certainly it could be piped in gasseous form and liquified there. So perhaps a separate but nearby platform for liquification/densification, with tanks. Delivering liquified propellant by boat would be less convenient. Maybe liquified propellants can be delivered by pipe, but it just seems difficult to me to keep it cold enough going that distance.
This was discussed up thread and the consensus seems to be that it is possible but you are going to have to recool on arrival or during storage.
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Offline biosehnsucht

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #582 on: 12/24/2017 07:48 AM »
With all the EIS issues, and potentially needing to go offshore fixed platform for BFR anyways, how much of a stretch would it be to just go offshore for Falcon 9/Heavy too? You could build one main causeway out a few miles, then have it split to separate pads, with the number of pads limited only by how much money you want to spend.

Run power and prop along this causeway too (prop either piped and re-chilled and stored per pad or perhaps just at the point where the causeway splits to the various pads, or truck/train/loop it there instead of pipes), rather than running plumbing underwater - saves you all the extra underwater welding in the case of piping it.

Offline speedevil

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #583 on: 12/24/2017 12:40 PM »
With all the EIS issues, and potentially needing to go offshore fixed platform for BFR anyways, how much of a stretch would it be to just go offshore for Falcon 9/Heavy too?

BFR is designed from the ground up for utterly minimal launch requirements.
Limited refurbishment, inspection, simple payload attachment, ...

F9H isn't.
'24h turnaround', with presumably most of that being touch-labour on the rocket is very different from pretty much land, gas and go.

You could of course do F9/H refurbishment and launch offshore, but the amount of hardware you need would be orders of magnitude more.

Offline Dave G

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #584 on: 12/24/2017 01:12 PM »
With all the EIS issues, and potentially needing to go offshore fixed platform for BFR anyways, how much of a stretch would it be to just go offshore for Falcon 9/Heavy too?

SpaceX already has 3 pads. There's been a lot of discussion about whether SpaceX needs a 4th pad for Falcon 9. 

LC-40 was not just rebuilt, it was also upgraded.  SpaceX said those upgrades should allow faster turnaround times.

The market for geosynchronous satellites seems to be shrinking lately. SpaceX said Boca Chica was mainly for GTO.

Then there's Starlink.  NSF folks have posted various launch calculations on this.  Some show they can do fine with their 3 existing pads, even if a pad goes down for a while.  Some show they'll need a 4th F9 pad.  All of this is speculative.

There are also public relations issues.  SpaceX originally said they may be launching from Boca Chica as soon as 2016, leading to many new jobs in the area.  In response to this, State and Local governments gave SpaceX various incentives.  Assuming SpaceX could launch F9 by this time next year, that would already be 2 years late.  If they delay another 2 years for a BFR-only launch site, public sentiment may turn against SpaceX.

So I'm unsure whether they'll launch F9 from Boca Chica or not.  I can see arguments both for and against.

I'm fairly certain they'll launch BFR from Boca Chica, but I'm not sure if it will be from Boca Chica Beach, or from an offshore launch pad.

You could build one main causeway out a few miles, then have it split to separate pads, with the number of pads limited only by how much money you want to spend.

Run power and prop along this causeway too (prop either piped and re-chilled and stored per pad or perhaps just at the point where the causeway splits to the various pads, or truck/train/loop it there instead of pipes), rather than running plumbing underwater - saves you all the extra underwater welding in the case of piping it.
I think a causeway is highly unlikely.  Underwater cables and pipes are much cheaper.

I also think an offshore pad for Falcon 9 is highly unlikely.

SpaceX already has permission to launch F9/FH from Boca Chica Beach, and they plan to scrap F9/FH.

In September, Musk said they'll stop building Falcon 9 / Dragon, and switch to using BFR for launching satellites and servicing the space station.  The cost of launching BFR is less than launching Falcon 1, let alone Falcon 9.

So Falcon 9's days are numbered.  Why optimize something they plan to scrap?
« Last Edit: 12/24/2017 01:15 PM by Dave G »

Offline Radical_Ignorant

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #585 on: 12/24/2017 01:37 PM »
[...]
Note that a fixed BFR pad several miles offshore would presumably solve all of these potential issues.

Not sure how to count that, but offshore platforms for oil industry  - that's source of tech for possible SX offshore launch side - are really expensive*. In range of good hundreds of $millions. That's huge number, not sure if SX wan't to take that. That's different scale for oil industry and space launching industry. What's possible there is not always applicable here. And we don't know how hard those issues are to legally solve them talking to local gov. Talk is cheap, offshore platform definitely not.


* http://www.offshore-mag.com/articles/print/volume-72/issue-7/rig-report/reviewing-rig-construction-cost-factors.html

Offline Nomadd

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #586 on: 12/24/2017 01:46 PM »
I don't know if it's feasible to pipe liquified L2 and CH4 across 5 miles of ocean, but certainly it could be piped in gasseous form and liquified there. So perhaps a separate but nearby platform for liquification/densification, with tanks. Delivering liquified propellant by boat would be less convenient. Maybe liquified propellants can be delivered by pipe, but it just seems difficult to me to keep it cold enough going that distance.
Distance isn't the problem as much as time. You can pipe low pressure LNG 20 miles underwater, but that depends on a good enough flow rate to keep it from warming. Starting and stopping all the time would be an issue. Even if they did send liquid to a launch platform, they'd still be collecting a lot of gas during runup and need to deal with it somehow. Since they'd need chilling capacity in any case, and compressing it to liquid is easy once you have that, shipping it in gas form seems a lot simpler to me.
« Last Edit: 12/24/2017 01:46 PM by Nomadd »

Online nacnud

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #587 on: 12/24/2017 01:55 PM »
Couldn't you just run the pipe in a loop, out and back. Put chillers on the landward end and tap off the LNG at the pad once you're getting a good LNG flow at that end. Might even work for LOX too.

I do think an offshore pad or floating pad is extremely unlikely though.
« Last Edit: 12/24/2017 01:56 PM by nacnud »

Offline meekGee

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #588 on: 12/24/2017 01:55 PM »
I don't know if it's feasible to pipe liquified L2 and CH4 across 5 miles of ocean, but certainly it could be piped in gasseous form and liquified there. So perhaps a separate but nearby platform for liquification/densification, with tanks. Delivering liquified propellant by boat would be less convenient. Maybe liquified propellants can be delivered by pipe, but it just seems difficult to me to keep it cold enough going that distance.
Distance isn't the problem as much as time. You can pipe low pressure LNG 20 miles underwater, but that depends on a good enough flow rate to keep it from warming. Starting and stopping all the time would be an issue. Even if they did send liquid to a launch platform, they'd still be collecting a lot of gas during runup and need to deal with it somehow. Since they'd need chilling capacity in any case, and compressing it to liquid is easy once you have that, shipping it in gas form seems a lot simpler to me.
BFR can keep a small pipeline busy 24/7 if launched 1/day.
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Offline Nomadd

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #589 on: 12/24/2017 02:04 PM »

BFR can keep a small pipeline busy 24/7 if launched 1/day.
Small can actually be better for thermal reasons even though you have a greater surface area to volume ratio, because higher pressure allows for warmer liquid and higher speed means less time in the pipeline. I heard of fancy new insulating methods back in my Chevron days, but don't know how far they've gotten.
« Last Edit: 12/24/2017 03:56 PM by Nomadd »

Offline meekGee

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #590 on: 12/24/2017 02:46 PM »
I don't know if it's feasible to pipe liquified L2 and CH4 across 5 miles of ocean, but certainly it could be piped in gasseous form and liquified there. So perhaps a separate but nearby platform for liquification/densification, with tanks. Delivering liquified propellant by boat would be less convenient. Maybe liquified propellants can be delivered by pipe, but it just seems difficult to me to keep it cold enough going that distance.
Distance isn't the problem as much as time. You can pipe low pressure LNG 20 miles underwater, but that depends on a good enough flow rate to keep it from warming. Starting and stopping all the time would be an issue. Even if they did send liquid to a launch platform, they'd still be collecting a lot of gas during runup and need to deal with it somehow. Since they'd need chilling capacity in any case, and compressing it to liquid is easy once you have that, shipping it in gas form seems a lot simpler to me.
BFR can keep a small pipeline busy 24/7 if launched 1/day.
Follow up:

4000 tons over 80,000 seconds is 50 kg/second, ballpark.

Should split the two propellants since different densities...  LOX at 1, LNG at 0.5..

So need 40 kg/sec of LOX, and 10 of LNG.  Or 40 liters/sec LOX, and 20 of LNG.

15 cm (6") pipes, area is 0.018 m2, so for 0.1 m/sec flow we get 1.8 liters/second

So one OOM too small/slow

Go with 30 cm (1'), and we're there.

(Unless you make the O2 on the platform, in which case only the LNG pipe is necessary)
« Last Edit: 12/24/2017 02:48 PM by meekGee »
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Offline Austin Dave

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #591 on: 12/24/2017 03:01 PM »
How would SpaceX transport the BFR to a pad that's 5 miles out in the Gulf?  I know the scenario that Elon Musk presented is that it would be serviced and loaded at the pad, but that seems unrealistic.  It seems more realistic that it would be assembled on land, and then transported to the pad.  There are many things about the BFR that don't make sense, and I hope the future of Boca Chica doesn't depend on it.

If I had to guess how things will actually unfold I would think that the BFR will never happen as Musk presented it.  It's more likely that the F9 and FH, or something like them will be produced with the new Raptor engines.  It's hard to say whether a launch facility at Boca Chica will ever be built.  If SpaceX can do everything they want at Florida and Vandenburg why would they ever need to build a launch facility at Boca Chica.

Offline meekGee

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #592 on: 12/24/2017 03:26 PM »
How would SpaceX transport the BFR to a pad that's 5 miles out in the Gulf?  I know the scenario that Elon Musk presented is that it would be serviced and loaded at the pad, but that seems unrealistic.  It seems more realistic that it would be assembled on land, and then transported to the pad.  There are many things about the BFR that don't make sense, and I hope the future of Boca Chica doesn't depend on it.

If I had to guess how things will actually unfold I would think that the BFR will never happen as Musk presented it.  It's more likely that the F9 and FH, or something like them will be produced with the new Raptor engines.  It's hard to say whether a launch facility at Boca Chica will ever be built.  If SpaceX can do everything they want at Florida and Vandenburg why would they ever need to build a launch facility at Boca Chica.
Well...  Like many others on this forum, you're entitled to your opinion...

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Offline Lar

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #593 on: 12/24/2017 03:36 PM »
Can't colonize Mars with F9. Or even FH. So either BFR happens, or Musk is lying about his ambitions. 

Detailed debate of that is off-topic for here.

(NOTE: I was wearing my mod hat when I said that last part. .. some posts debating the point have been removed...)
« Last Edit: 12/24/2017 10:54 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 Nomadd

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #594 on: 12/24/2017 09:08 PM »
 Speaking of laying offshore pipeline, this guy has been working off the beach for a couple of weeks, I assume on the 42 inch Mexican network feeder. All SpaceX has to do is tune the engine to work with a little extra ethane and nitrogen and tap in.

 All the discussion of gas or liquid and what facilities the launch site will need to process the gas might also apply to the land site. With major gas/LNG facilities five miles away, a pipeline to a land pad might make more sense than hundreds of trucks going back and forth. The Annova facility they're building right now on the south side of the ship channel would be a pretty a pretty convenient supplier.
« Last Edit: 12/24/2017 09:15 PM by Nomadd »

Offline Lar

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #595 on: 12/24/2017 10:59 PM »
Speaking of laying offshore pipeline, this guy has been working off the beach for a couple of weeks, I assume on the 42 inch Mexican network feeder. All SpaceX has to do is tune the engine to work with a little extra ethane and nitrogen and tap in.
The removal of ethane and nitrogen is apparently quite easy during liquefaction which has to be done anyway.... I suspect that's probably a better approach than detuning the Raptor.  But yeah, it's natural to tap into one or more of the many different sources rather than trucking.
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"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline Avron

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #596 on: 12/24/2017 11:15 PM »
Removal of other gasses from the fuel is critical for engine combustion stability - you really don't want to deal with any pulsing on the injector .

Offline Austin Dave

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #597 on: 12/25/2017 12:47 AM »
It seems like most of the discussion on this thread has been about things other than the SpaceX Texas launch site.  Mostly because there hasn't been any direct activity on the launch site in over a year.  There has been work on Stargate, the tracking antennas and a warehouse for crane parts.  Also the highway has been widened and utility conduits have been laid along the road.  I'm just curious -- has there been any construction activity at all in 2017 on the control center, HIF or the launch pad?

Offline Nomadd

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #598 on: 12/25/2017 01:00 AM »
It seems like most of the discussion on this thread has been about things other than the SpaceX Texas launch site.  Mostly because there hasn't been any direct activity on the launch site in over a year.  There has been work on Stargate, the tracking antennas and a warehouse for crane parts.  Also the highway has been widened and utility conduits have been laid along the road.  I'm just curious -- has there been any construction activity at all in 2017 on the control center, HIF or the launch pad?
Nope. Not sure if they know what they're going to construct yet.

Offline Roy_H

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Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #599 on: 12/25/2017 02:06 AM »
It seems like most of the discussion on this thread has been about things other than the SpaceX Texas launch site.  Mostly because there hasn't been any direct activity on the launch site in over a year.  There has been work on Stargate, the tracking antennas and a warehouse for crane parts.  Also the highway has been widened and utility conduits have been laid along the road.  I'm just curious -- has there been any construction activity at all in 2017 on the control center, HIF or the launch pad?
Nope. Not sure if they know what they're going to construct yet.

Which is exactly why we talk about everything else.

So, I figure I will add my own speculation: For a long time I thought that the off-shore launch platform was a silly idea, but the more I think about it there are several advantages. First I believe the best form would be like an oil rig, standing on the ocean floor and high above the highest ocean waves. I believe you need a stable platform, not a floating one. Pipe fuel, power etc. on ocean floor. Dig a channel next to the hill they made for the HIF for a boat/barge to carry the rocket to the launch pad. Extend the HIF crane rails out over the channel so the rocket (and TEL?) can be lowered on to the barge. This would be far cheaper than even a short causeway. Doesn't require driving hundreds of piles or otherwise trying to stabilize the land for the launch pad and causeway to it as originally envisioned. Modify a used oil rig and I think this would be cheaper and quicker than the land version.
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