Author Topic: SpaceX Texas launch site Discussion and Updates - Thread 6  (Read 507449 times)

Online meekGee

  • Senior Member
  • *****
  • Posts: 8765
  • N. California
  • Liked: 4959
  • Likes Given: 904
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #560 on: 12/20/2017 03:38 AM »
1812 overture finale...  Timed just right...  krakawoooosh!
ABCD - Always Be Counting Down

Offline Dave G

  • Senior Member
  • *****
  • Posts: 2243
  • Liked: 996
  • Likes Given: 1194
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #561 on: 12/20/2017 10:45 AM »
I am quite sure it is for concerts as well and only additional for launch watching.

And general partying.  It looks like there's a dance floor right next to the shoreline.

Offline SPITexas

  • Full Member
  • ***
  • Posts: 331
  • Liked: 84
  • Likes Given: 2
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #562 on: 12/20/2017 02:17 PM »
Not related to this thread but wanted to show you what SpaceX most powerful rocket will look like. Note: this is real for real.

Offline Nomadd

  • Senior Member
  • *****
  • Posts: 3353
  • Boca Chica, Texas
  • Liked: 5985
  • Likes Given: 360
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #563 on: 12/20/2017 03:49 PM »


For a solar array, I believe the low voltage DC wires are larger, i.e. higher amperage. Also I imagine there would be more low voltage DC wires than high voltage AC wires.

They could be using micro-inverters, but with the potential for hurricanes and flooding, I'm guessing traditional inverters located on the concrete slabs.
It will probably be high voltage DC. I'm mostly wild guessing 6 arrays per rack, which would be 216 volts if they were in series. I wouldn't be surprised if they went to the 400 volt range for DC, since that would keep wiring size down and be the same range the Model S uses. (Not sure what the model 3 is) It looks like the CS6U array can handle up to 1500 volts to ground.
 The details of how or if they're tying into the grid should be interesting. With a transfer switch just west of the STARGATE building they could possibly take over the whole grid east of there with public juice for backup or times you don't see the sun for a week.

 It turns out they're going to run the solar DC at 1,000 volts.

 The crane garage is almost there. It has half a roof now.
« Last Edit: 12/20/2017 04:00 PM by Nomadd »

Offline Dave G

  • Senior Member
  • *****
  • Posts: 2243
  • Liked: 996
  • Likes Given: 1194
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #564 on: 12/20/2017 06:27 PM »
It turns out they're going to run the solar DC at 1,000 volts.

Wow.  I'm guessing that's around 28 panels in series.  So if any of these fail, the whole string goes out, yes?

Offline Nomadd

  • Senior Member
  • *****
  • Posts: 3353
  • Boca Chica, Texas
  • Liked: 5985
  • Likes Given: 360
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #565 on: 12/20/2017 06:43 PM »
It turns out they're going to run the solar DC at 1,000 volts.

Wow.  I'm guessing that's around 28 panels in series.  So if any of these fail, the whole string goes out, yes?
There are several ways they could do it. The setup in that big a string might be that a 35 volt drop doesn't hurt much and they could bypass individual panels. Even the number of panels in series is a little fuzzy since voltage per panel is anywhere from 35 to 46 volts depending on the load. I don't know how they're going to feed the strings into the charger/inverter/whatever, but I wouldn't think it would just be tying them all straight together.

Offline John Alan

  • Full Member
  • ****
  • Posts: 781
  • Central IL - USA - Earth
  • Liked: 473
  • Likes Given: 1906
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #566 on: 12/20/2017 07:18 PM »
Typically if your doing high voltage PV (600 or 1000v)...
You do one series string till open circuit voltage on the coldest day is just under limit and feed it to one inverter...
So say 20 panels with 48v open circuit volts on the coldest day of the year... just under 1000v
The invertors are MPPT type and load it down to well under that... say 800-900v range in bright sun...
850v and say 12 amps... 10kw inverter on each string...
Reality is PV's are solid state and either fail on infant mortality or from damage (storm, vandals, etc)
SO... big systems they go ahead and run series/parallel... and go with much bigger inverters...
And, there is usually some sort of monitor on the combiner box... that isolates and flags out of service strings needing inspection/repair...

Nice thing about Texas...
You don't have -30 below F days with open circuit voltage out the roof to deal with like we have here sometimes to remember to plan for...
That said... PV likes the cold... they work better the colder it is...  ;)
« Last Edit: 12/20/2017 07:26 PM by John Alan »

Offline Nomadd

  • Senior Member
  • *****
  • Posts: 3353
  • Boca Chica, Texas
  • Liked: 5985
  • Likes Given: 360
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #567 on: 12/20/2017 09:20 PM »
 I haven't worked with the newer stuff, but with older panels, it only took a tiny load to bring the open circuit voltage way down.

Offline cscott

  • Senior Member
  • *****
  • Posts: 2949
  • Liked: 2056
  • Likes Given: 664
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #568 on: 12/21/2017 12:20 AM »
Yeah the MPPT circuits make a huge difference in solar panel efficiency.  Getting the I/V in the sweet spot is a big deal. MPPT becoming cheaper with the general cheaper-electronics trend is one of the ways solar has gotten better faster than raw solar panel efficiency has improved.

At One Laptop per Child my coworker integrated MPPT directly into our battery-charging electronics to make cheap solar panels charge our laptops really well.

Offline Lar

  • Fan boy at large
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 10795
  • Saw Gemini live on TV
  • A large LEGO storage facility ... in Michigan
  • Liked: 7717
  • Likes Given: 5556
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #569 on: 12/21/2017 12:41 AM »
Yeah the MPPT circuits make a huge difference in solar panel efficiency.  Getting the I/V in the sweet spot is a big deal. MPPT becoming cheaper with the general cheaper-electronics trend is one of the ways solar has gotten better faster than raw solar panel efficiency has improved.

At One Laptop per Child my coworker integrated MPPT directly into our battery-charging electronics to make cheap solar panels charge our laptops really well.
You were involved in OLPC? I salute you sir. I had some wikimedian friends involved in that. One has to wonder how much better OLPC would be now.
"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

Online vaporcobra

  • Full Member
  • ****
  • Posts: 1179
  • Tacoma, WA
  • Liked: 2208
  • Likes Given: 2481
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #570 on: 12/21/2017 06:55 AM »
Sunset on the eve of winter solstice in Texas :) Courtesy of an Instagram user, username withheld for privacy.

Offline Nomadd

  • Senior Member
  • *****
  • Posts: 3353
  • Boca Chica, Texas
  • Liked: 5985
  • Likes Given: 360
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #571 on: 12/23/2017 12:52 AM »
 Large, gray metal things are making themselves known. I hope they realize it's going to rain tonight.
« Last Edit: 12/23/2017 04:45 AM by Nomadd »

Offline UKobserver

  • Member
  • Posts: 28
  • Liked: 73
  • Likes Given: 20
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #572 on: 12/23/2017 03:24 AM »
Whatever the original plan may have been, I think SpaceX is now going to use BC as their prototype BFR/BFS launch pad, where they can experiment, iterate and learn lessons before modifying/building pads elsewhere. Here is the basis for my rationale;

Firstly I agree that SpaceX will want to keep their pad crew construction busy, and will move them onto their next project as soon as they finish preparing 39A for FH. However I think they have several other priorities before they can tackle Boca Chica. The Crew Access Arm at 39A is one, to enable Commercial Crew, vertical integration hardware at 39A is another, to secure those contracts (not sure if they have a deadline for when this is needed), and I think upgrading SLC-4E for faster pad turnaround between launches (throwback etc) is likely to be another. They seem to have more Vandenberg payloads than they can launch at the moment, and I can imagine they would want to remove that constraint, particularly with Starlink coming up. So my first thought is that they may not be ready to work on BC for quite a while (6-18mths). That might explain the shed around the crane.

I also agree that they now have a surplus of capacity on the east coast. With both LC-39A and SLC-40 now capable of 2 week turnarounds (and SpaceX seem to be working on reducing that further), each of those pads is theoretically capable of 24 launches per year, or in reality more like 20 when the range maintenance period, weather etc are factored in. Given their stated aim of increasing launch cadence 50% in 2018 (27-33 planned launches?), and with Vandenberg currently capable of 8-10 of those, they could very nearly achieve that objective even if they lost one of their east coast pads. It wouldn't be great for them, as they would then be struggling to fit all their contracted launches in, but it's just about doable, and not too many would slip to the right in the near term. In the mid-term that could become an issue though, as I don't think one pad would be enough on the east coast once they are ready to start launching Starlink in earnest. So the window of opportunity where they can get away with one east coast pad isn't very long, and it's risky, as AMOS-6 proved. But for now the limiting factor seems to be production and refurbishment of boosters. So the need for BC from a near-term F9 launch pad availability perspective has diminished significantly.

However we do know that they want to make rapid progress on BFR/BFS, and that means they are going to want to start conducting static fires, sub-orbital and full orbital launches as soon as they have vehicle hardware ready, which means they need a pad/facility in place to do so. I don't know how long people envisage them taking to build the first spaceship or booster but to make their stated 2022 Mars window they have to be aiming for 2020 I would think to start testing. So the question is; where will that first pad be?

The consensus seems to be that LC-39A will become a BFR/BFS pad, and I agree that is likely long-term, but I don't believe it will be the first. More knowledgeable commentators may like to weigh in here, but the amount of construction/modification that I envisage would be needed at LC-39A makes me think that they would have to take it off-line in order to do the work. I think it would be too dangerous/complicated/disruptive to try to slot all that work in-between launches. But if they were to take LC-39A offline before BC was constructed then they are back to being constrained by east coast pad slots, and in danger of having no east coast launch pad at all if LC-40 were to suffer another accident during construction at LC-39A, which is a big risk to their cashflow. They could solve that problem by building BC as a Falcon 9 pad first, before then rebuilding 39A for BFR, but that would massively delay testing of BFR, so I don't think they will do that.

So the most logical solution for me is; leave LC-39A and SLC-40 alone, now that they are both operating efficiently and effectively. Let those pads work through the east coast manifest and earn the revenue SpaceX needs to fund everything else. Meanwhile, once the pad crews have finished their other tasks, they can then move down to Boca Chica and with a blank canvas to work with, build a first prototype of a BFR pad. It wont be perfect to start with, but they'll learn lessons as they test the first few BFR/BFS vehicles, they'll implement pad upgrades based on those lessons and iterate as they have done with their other pads.

I can see them starting to trial launching their own Starlink satellites from BC as soon as BFR/BFS has proven itself capable of reaching orbit; if you're making experimental test launches then you might as well send a few each time, especially if they hit their cost targets for Starlink. They will need BFS to make a second burn as it crosses the equator, increasing the inclination of the orbit to reach that desired for each Starlink orbital plane, but I don't see that being any more difficult than reducing inclination over the equator, which they do every time they launch a GTO satellite. And with BFR they have an absolutely enormous payload capability to play with, so they can afford to trade some of that payload for the fuel needed to increase inclination. And fuel is cheap, as Elon has pointed out. At the same time they are testing boostback and landing, and inspecting boosters and learning what needs refurbishing on them.

Once they have proven their capability to launch high-inclination east coast satellites from Boca Chica, and assuming they are by that point able to get multiple reflights out of each BFR/BFS (thus amortizing the high unit cost of each over many flights), then they can switch half of their east coast launches from LC-39A down to BC and then take 39A offline in order to convert it to a BFR/BFS pad (or dual-use if they wish). By that point they should be far enough down the learning curve that LC-39A can be built to a more robust (version 2) design.

At some point they will also need to build a BFR/BFS pad at Vandenberg. Thinking about it; they might choose to do that after BC and before LC-39A, because they would want a west coast pad for Starlink as soon as possible, and there's no point them having massive capacity on the east coast (BFR from both BC + 39A, plus F9 from 40) while they're struggling to manage with F9/FH from one pad at Vandenberg. So possibly the pad crew will move to the west coast next and then LC-39A after that. Or by then they may have trained up a second pad crew and be able to do both at the same time, a capability they will need to have sooner or later if they genuinely want to build enough pads to realise their plans of flying point to point to multiple locations around the world.

So that's the order I think things will happen. Short of abandoning BC altogether and building a completely new pad for BFR/BFS at Cape Canaveral (LC-39C or D were considered by NASA at one time I believe?) I don't think they have much option, without either delaying BFR or constraining themselves on the east coast. They could possibly get away with just using LC-40 for a couple of years if they could further reduce the turn-around time between launches, but that would be at the risk of being without an east coast pad altogether if something goes wrong, and might also leave them short of capacity once they wish to be deploying Starlink in earnest.

I guess ultimately we'll have to wait and see. Hope some of you managed to wade through that!

Offline Dave G

  • Senior Member
  • *****
  • Posts: 2243
  • Liked: 996
  • Likes Given: 1194
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #573 on: 12/23/2017 03:39 AM »
Large, gray metal things are making themselves know. I hope they realize it's going to rain tonight.

I suspect those enclosures will be used for inverters and other electronics.

If they're going to add batteries to this solar array, which hasn't yet been confirmed, these would presumably be Tesla PowerPacks, which are white, and look quite different.

Offline Zed_Noir

  • Senior Member
  • *****
  • Posts: 2559
  • Canada
  • Liked: 401
  • Likes Given: 598
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #574 on: 12/23/2017 03:46 AM »
<snip>
At some point they will also need to build a BFR/BFS pad at Vandenberg. Thinking about it; they might choose to do that after BC and before LC-39A, because they would want a west coast pad for Starlink as soon as possible, and there's no point them having massive capacity on the east coast (BFR from both BC + 39A, plus F9 from 40) while they're struggling to manage with F9/FH from one pad at Vandenberg. So possibly the pad crew will move to the west coast next and then LC-39A after that. Or by then they may have trained up a second pad crew and be able to do both at the same time, a capability they will need to have sooner or later if they genuinely want to build enough pads to realise their plans of flying point to point to multiple locations around the world.
<snip>

Or SpaceX can build a fleet of BFR sized ASDS floating platforms after where ever they chose as the first BFR pad. Especially if they start the P2P (point to point) service with the BFR.

Offline Dave G

  • Senior Member
  • *****
  • Posts: 2243
  • Liked: 996
  • Likes Given: 1194
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #575 on: 12/23/2017 04:02 AM »
Or SpaceX can build a fleet of BFR sized ASDS floating platforms after where ever they chose as the first BFR pad.
I think a floating platform to launch and land BFR/BFS is highly unlikely.  Way more issues here.  For a rocket that big, a floating platform would probably need to be huge, which would be really expensive.

Fixed launch pads several miles offshore seem much more likely.  These would have legs that physically connect with the ocean floor, with cables and pipelines connecting back to land.  This arrangement is very typical in the oil and gas industry, so it would probably be relatively economical.

Especially if they start the P2P (point to point) service with the BFR.
For this, Elon's presentation showed a small launch platform several miles offshore.  This implies a fixed launch platform that's physically connected to the ocean floor.  A floating platform for a BFR size rocket would probably need to be an order of magnitude larger.
« Last Edit: 12/23/2017 05:08 AM by Dave G »

Offline Dave G

  • Senior Member
  • *****
  • Posts: 2243
  • Liked: 996
  • Likes Given: 1194
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #576 on: 12/23/2017 05:02 AM »
So my first thought is that they may not be ready to work on BC for quite a while (6-18mths). That might explain the shed around the crane.
I've thought the same, but as others have mentioned upthread, delaying that long could be a public relations issue for SpaceX in South Texas. So I'm unsure whether F9 will launch from BC or not.

But for now the limiting factor seems to be production and refurbishment of boosters.
Why do you say this?

However we do know that they want to make rapid progress on BFR/BFS, and that means they are going to want to start conducting static fires, sub-orbital and full orbital launches as soon as they have vehicle hardware ready, which means they need a pad/facility in place to do so. I don't know how long people envisage them taking to build the first spaceship or booster but to make their stated 2022 Mars window they have to be aiming for 2020 I would think to start testing. So the question is; where will that first pad be?
Note that there's a separate thread titled "Where will BFR launch from first? and When will that be?":
http://forum.nasaspaceflight.com/index.php?topic=44168.0;all

So the most logical solution for me is; leave LC-39A and SLC-40 alone, now that they are both operating efficiently and effectively...
Note that many have speculated about the possibility of a fixed pad several miles offshore, both for Boca Chica and Florida.

Once they have proven their capability to launch high-inclination east coast satellites from Boca Chica, and assuming they are by that point able to get multiple reflights out of each BFR/BFS (thus amortizing the high unit cost of each over many flights), then they can switch half of their east coast launches from LC-39A down to BC and then take 39A offline in order to convert it to a BFR/BFS pad (or dual-use if they wish)...
For test flights of BFR and/or BFS from Boca Chica, SpaceX would need to seek approval from the Federal Avaition Administraion. As part of this approval process, the FAA is required to have a public comment period. A public comment period means we'd know if/when SpaceX is seeking additional approvals for BC.  So far, it appears they have not.

To clarify, Boca Chica is currently limited to:
• a mamimum of 12 total launches per year
• a mamimum of 2 Falcon Heavy launches per year
• no test flights of any launch vehicle larger than Falcon 9
• no launches on summer weekends or holidays, due to Texas public beach closure laws

Also, the current EIS notes that the noise level for Falcon Heavy is actually 2dB over the legal limit in Boca Chica Village, but the FAA let this slide because:
• There are not many people living in Boca Chica Village
• SpaceX offered to hand out earplugs to all local residents before every FH launch
• They're only allowed 2 Falcon Heavy launches per year

In addition, the whole area surrounding the launch site is environmentally protected wetlands.  For example, the phrase "sea turtle" is mentioned 96 times in the EIS. Since sea turtles are an endangered species, this could also cause limitations.  For example, a BFR sized flame trench may not be allowed.

Note that a fixed BFR pad several miles offshore would presumably solve all of these potential issues.

Offline SPITexas

  • Full Member
  • ***
  • Posts: 331
  • Liked: 84
  • Likes Given: 2
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #577 on: 12/23/2017 02:19 PM »
We have not heard any news of SpaceX abondoning or delaying the site Contruction.  I wouldn’t guess its being delayed Becuase of a crane, that’s for the BFR. It is still planned after LC-40 is active and after they launch a possible successful launch of the Falcon Heavy in January your right they’ll come over to Boca Chica. We’ve barely seen anything happen some of us are pretty confident they’ll be activity. They still want this launch site to happen and yes it could be a back up launch site if anything happens to the other ones so Boca Chica isn’t forgotten.

Offline RDMM2081

  • Full Member
  • *
  • Posts: 139
  • Liked: 75
  • Likes Given: 126
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #578 on: 12/23/2017 06:32 PM »
In regards to floating or otherwise offshore launch pads, I am curious what the "TRL" of maritime delivery of LOX/LNG is?  I assume a fixed pad offshore could be plumbed in some way to pipeline the LOX/LNG directly to staging tanks, or directly to the booster?  But if the case were in fact a floating pad, would it be possible to use flexible pipelines? Would they have necessary insulation to deliver densified LOX?  Since I assume this is not feasible to use flexible temporary pipelines, is ship-based delivery of these propellants a reasonable option?

Offline Lar

  • Fan boy at large
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 10795
  • Saw Gemini live on TV
  • A large LEGO storage facility ... in Michigan
  • Liked: 7717
  • Likes Given: 5556
Re: SpaceX Texas launch site Discussion and Updates - Thread 6
« Reply #579 on: 12/23/2017 08:54 PM »
Depending on how and where the platform is constrained, it is possible to have piping deliver to a floating platform. But it needs to be pretty tightly constrained. Free in the vertical direction only is probably the easiest to design for.
"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

Tags: