Author Topic: Pad 39A - SpaceX Modifications and Operations (Thread 4)  (Read 264877 times)

Offline AS_501

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #500 on: 05/07/2023 03:41 pm »
Given the 39A lightning hit the other day (FH/Viasat), I've never understood why 39A  was never equipped with three or four lightning towers like 39B, 40, 41, etc.  My limited understanding is that the cables strung between multiple towers create essentially a protective 'cage' (Faraday?) around the pad facilities and launch vehicle.  Of course, the SS/SH tower may affect these considerations.
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Offline EspenU

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #501 on: 05/07/2023 04:31 pm »
Given the 39A lightning hit the other day (FH/Viasat), I've never understood why 39A  was never equipped with three or four lightning towers like 39B, 40, 41, etc.  My limited understanding is that the cables strung between multiple towers create essentially a protective 'cage' (Faraday?) around the pad facilities and launch vehicle.  Of course, the SS/SH tower may affect these considerations.
I'm no expert in this field, but isn't the recent lightning strike "proof" that they don't need more towers than the one they have?
If the strike had affected the rocket and delayed the launch, I would have seen your point, but everything seemes to have been fine.

Offline phantomdj

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #502 on: 05/07/2023 05:55 pm »
Given the 39A lightning hit the other day (FH/Viasat), I've never understood why 39A was never equipped with three or four lightning towers like 39B, 40, 41, etc.  My limited understanding is that the cables strung between multiple towers create essentially a protective 'cage' (Faraday?) around the pad facilities and launch vehicle.  Of course, the SS/SH tower may affect these considerations.

The pad as been hit many times both in the shuttle era (at least a dozen times) and the SpaceX era. Never has a vehicle been hit (except Apollo 12 which had cleared the tower and created its own ionized path to ground). The lightning mast on top of the Pad 39a tower is as tall as an old redstone rocket (~70 ft) and has a Catenary Wire System on top that leads to ground anchor points located 1000 ft away, directing lightning currents away from the vehicle providing a cone of protection.
SpaceX has become what NASA used to be in the '60's, innovative and driven.

Offline AS_501

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #503 on: 05/07/2023 10:19 pm »
Given the 39A lightning hit the other day (FH/Viasat), I've never understood why 39A was never equipped with three or four lightning towers like 39B, 40, 41, etc.  My limited understanding is that the cables strung between multiple towers create essentially a protective 'cage' (Faraday?) around the pad facilities and launch vehicle.  Of course, the SS/SH tower may affect these considerations.

The pad as been hit many times both in the shuttle era (at least a dozen times) and the SpaceX era. Never has a vehicle been hit (except Apollo 12 which had cleared the tower and created its own ionized path to ground). The lightning mast on top of the Pad 39a tower is as tall as an old redstone rocket (~70 ft) and has a Catenary Wire System on top that leads to ground anchor points located 1000 ft away, directing lightning currents away from the vehicle providing a cone of protection.

Now that you mention it, I do remember seeing those catenary wires.  Thanks!
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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #504 on: 06/07/2023 06:51 am »
What did happen at pad few hours ago? Explosion of LOX tank?

Offline EspenU

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #505 on: 06/07/2023 07:02 am »
What did happen at pad few hours ago? Explosion of LOX tank?
Care to elaborate with any reports or stream screenshots? First I'm hearing of anything..

Offline catdlr

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #506 on: 06/07/2023 07:02 am »
What did happen at the pad a few hours ago? An explosion of LOX tank?

Could you go back to the live stream and provide the timestamp?
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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #507 on: 06/07/2023 07:10 am »
What did happen at pad few hours ago? Explosion of LOX tank?

Without timestamps, pictures, etc it's impossible to know what you're referring to. Looking back on the livestream there's really nothing out of the ordinary to be seen at 39A. You sure you were looking at the right thing?

Offline catdlr

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #508 on: 06/07/2023 07:12 am »
What did happen at pad few hours ago? Explosion of LOX tank?

Without timestamps, pictures, etc it's impossible to know what you're referring to. Looking back on the livestream there's really nothing out of the ordinary to be seen at 39A. Are you sure you were looking at the right thing?

I reviewed it myself, 4 hours backward, that's why I asked him for a timestamp.
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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #509 on: 06/07/2023 08:24 am »
What did happen at pad few hours ago? Explosion of LOX tank?
Care to elaborate with any reports or stream screenshots? First I'm hearing of anything..
This was told to me by a man who was there not far away. You could also hear the sirens of the fire trucks.

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #510 on: 07/30/2023 07:33 pm »
What's the current status of LH2 GSE at 39A? Hypothetically could 39A support propellant loading of a Centaur V?

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Offline russianhalo117

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #511 on: 07/30/2023 07:45 pm »
What's the current status of LH2 GSE at 39A? Hypothetically could 39A support propellant loading of a Centaur V?

Hashtags: #frankenrocket #speculation #alternate-history
LH2 GSE has already been converted to CH4 and lines to Apollo era LC-39A have already been cut and capped off as the retained GSE lines from the flare stack and tank farm now go towards the backside of tbe base of the new Starship pads' OLIT.
« Last Edit: 07/30/2023 07:45 pm by russianhalo117 »

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #512 on: 11/17/2023 08:13 am »
twitter.com/nasaspaceflight/status/1725345400192672049

Quote
Meanwhile, at KSC....fire department rolling down the crawlerway and 39A's FSS (Fixed Service Structure) is going rather bonkies with the LEDs. Never seen it acting like a Christmas tree before.

nsf.live/spacecoast

https://twitter.com/julia_bergeron/status/1725362021439316070

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Windy, wet weather and alarm strobes. Hopefully the alarm was triggered by weather and nothing too disruptive is going on.
« Last Edit: 11/17/2023 08:14 am by FutureSpaceTourist »

Offline ChrisC

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #513 on: 11/17/2023 02:13 pm »
For the record, I'll also capture the context that Julia was referencing.  ChrisB said:

Quote
Meanwhile, at KSC....fire department rolling down the crawlerway and 39A's FSS (Fixed Service Structure) is going rather bonkies with the LEDs. Never seen it acting like a Christmas tree before.
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Offline launchwatcher

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #514 on: 11/17/2023 04:16 pm »
For the record, I'll also capture the context that Julia was referencing.  ChrisB said:

Quote
Meanwhile, at KSC....fire department rolling down the crawlerway and 39A's FSS (Fixed Service Structure) is going rather bonkies with the LEDs. Never seen it acting like a Christmas tree before.
For those who may not be aware, fire alarm systems are now commonly required to include flashing strobe lights to attract the attention of those who either can't hear or are wearing hearing protection.   

Offline drnscr

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #515 on: 11/18/2023 03:43 am »
So, what’s the answer on what was happening at 39-A Thursday night?

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #516 on: 02/28/2024 01:05 pm »
https://twitter.com/julia_bergeron/status/1762840821483942389

Quote
The tower at 39A looks a bit different since the last time a Dragon was at the pad for AX-3. The work we've seen resulted in all of the cladding being removed, letting the sun shine through.

Live views of Crew-8 preps
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Offline ChrisC

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #517 on: 02/28/2024 09:02 pm »
Quote
The tower at 39A looks a bit different since the last time a Dragon was at the pad for AX-3. The work we've seen resulted in all of the cladding being removed, letting the sun shine through.

This post from Julia confused me at first because her photo still showed cladding on one side (so, definitely not "all" of the cladding removed), and the angle didn't show the lack of cladding on the second side, so seemed like none of the cladding had been removed.  (And recent Twitter dysfunction means I couldn't see the NASA CC tweet that she was quoting, which clearly does show the lack of cladding on the second side.)

So, to clarify, SpaceX appears to have removed all of the cladding on one of the two sides that were previously clad.  Although, I'm still confused by the angles here, so I'm looking forward to someone ELI5-ing me :)
« Last Edit: 02/28/2024 09:08 pm by ChrisC »
PSA #1: EST does NOT mean "Eastern Time".  Use "Eastern" or "ET" instead, all year round, and avoid this common error.  Google "EST vs EDT".
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Online edzieba

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Re: Pad 39A - SpaceX Modifications and Operations (Thread 4)
« Reply #518 on: 02/29/2024 09:43 am »
Quote
The tower at 39A looks a bit different since the last time a Dragon was at the pad for AX-3. The work we've seen resulted in all of the cladding being removed, letting the sun shine through.

This post from Julia confused me at first because her photo still showed cladding on one side (so, definitely not "all" of the cladding removed), and the angle didn't show the lack of cladding on the second side, so seemed like none of the cladding had been removed.  (And recent Twitter dysfunction means I couldn't see the NASA CC tweet that she was quoting, which clearly does show the lack of cladding on the second side.)

So, to clarify, SpaceX appears to have removed all of the cladding on one of the two sides that were previously clad.  Although, I'm still confused by the angles here, so I'm looking forward to someone ELI5-ing me :)
The two images are before-and-after. One has cladding all down the rocket-facing side of the tower, the other does not.

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