Author Topic: Launchpad lighting. Technology, considerations, tradeoffs, etc.  (Read 921 times)

Offline manoweb

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Extraordinary claim typically requires extraordinary evidence, of course I did a quick search and the term came up indeed - but it felt like who was writing was not a lightning tech. It would be cool to start a separate thread on this issue, but I am not sure there are enough people that care.

This is a thread to discuss lighting as it applies to spacecraft, especially launch pads, but other applications are fair game too, as long as it is clearly spacecraft related. We're a site that's all about the launchers, after all...

Edit/Lar: Manoweb, what do you want the header to say, PM me, or just edit it yourself. Headers are good places for links to external resources or other discussions where the topic was mentioned, etc...
« Last Edit: 03/16/2017 09:41 AM by Lar »

Offline Lee Jay

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Extraordinary claim typically requires extraordinary evidence, of course I did a quick search and the term came up indeed - but it felt like who was writing was not a lightning tech. It would be cool to start a separate thread on this issue, but I am not sure there are enough people that care.

They used Xenon because you can get crazy-bright Xenon lights (i.e. 15kW versus 1-2kW for metal halide).

https://www.alibaba.com/product-detail/event-attractions-Xenon-lamp-sky-searchlights_60173934395.html

Offline manoweb

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I stand corrected, apparently xenon lights are commonly used as search lights, and the bulb in the alibaba page is definitely a short arc xenon. I did not know this until now, thanks for the info!

Offline OnWithTheShow

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They used Xenon because you can get crazy-bright Xenon lights (i.e. 15kW versus 1-2kW for metal halide).

https://www.alibaba.com/product-detail/event-attractions-Xenon-lamp-sky-searchlights_60173934395.html

To clarify.... kW is not a measure of brightness.

Offline Lar

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They used Xenon because you can get crazy-bright Xenon lights (i.e. 15kW versus 1-2kW for metal halide).

https://www.alibaba.com/product-detail/event-attractions-Xenon-lamp-sky-searchlights_60173934395.html

To clarify.... kW is not a measure of brightness.
Lumens I think. so the more lumens per watt of energy, the better, (hence the drive to replace incandescent with fluoro and LED household lights)  but also absolute brightness is important which might be the Xenon reason?

Is the topic of lighting up launch pads sufficiently interesting to warrant a splinter thread? PM me or report to mod and it might happen.
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Offline Zach Swena

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LED are efficient at producing light for lumens/watt, but at the kw equivalent power levels they would be very expensive.  I would expect that spacex wouldn't consider upgrading them to LED unless they have to foot the bill for running them 24/7 for long periods of time.

Offline Jim

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LED are efficient at producing light for lumens/watt, but at the kw equivalent power levels they would be very expensive.  I would expect that spacex wouldn't consider upgrading them to LED unless they have to foot the bill for running them 24/7 for long periods of time.

They aren't Spacex's lights.  They are the range's.  And they are used by multiple groups.

Offline manoweb

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LED are efficient at producing light for lumens/watt

Compared to incandescent, but HID lights are much more efficient than LEDs when you consider the lumen/Watt; in fact even fluorescent is better than LED in this regard. LED fares better when you measure the luminous flux as they are inherently directional but I think in a search light the parabolic mirror is carefully engineered to create a very high lux/W ratio too.

Plus the spectrum of a Xenon light puts LEDs to shame, but this may not be important for a pad.

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Current home lights LED beats compact fluorescent and 4' tube fluorescent for efficiency. I thought they also beat discharge type which includes high pressure sodium, mercury and HID. Of course gas discharge come in greater total lumens.
« Last Edit: 03/09/2017 10:24 AM by rsdavis9 »
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Offline eweilow



They used Xenon because you can get crazy-bright Xenon lights (i.e. 15kW versus 1-2kW for metal halide).

https://www.alibaba.com/product-detail/event-attractions-Xenon-lamp-sky-searchlights_60173934395.html

To clarify.... kW is not a measure of brightness.
No, but you get a pretty good idea of the brightness when comparing a light that draws 15kW to one that draws 1-2kW. Assuming that we're not talking about a space heater lamp.
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Offline JamesH65

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They used Xenon because you can get crazy-bright Xenon lights (i.e. 15kW versus 1-2kW for metal halide).

https://www.alibaba.com/product-detail/event-attractions-Xenon-lamp-sky-searchlights_60173934395.html

To clarify.... kW is not a measure of brightness.
No, but you get a pretty good idea of the brightness when comparing a light that draws 15kW to one that draws 1-2kW. Assuming that we're not talking about a space heater lamp.

Not if you compare incandescent with LED or fluorescent.

Offline Lar

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Bump. This is now a separate topic, in the general section, so it's not SpaceX specific. I'd love to hear more about how other pads are lit, and other lighting topics...

for example, to give you ideas of what's on topic.... discussion about whether there are special lighting considerations inside payload cleanrooms, or maintenance areas for vehicles (UV damages ABS so we tend to avoid a lot of fluoros when lighting our LEGO models... any such considerations for satellites or launchers? The exterior has to stand direct sunlight which is full spectrum, but what about while working on the guts???)
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Offline Jim

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Bump. This is now a separate topic, in the general section, so it's not SpaceX specific. I'd love to hear more about how other pads are lit,

They are lit by the exact same lights.  They are a range resource and shared among all the users.


for example, to give you ideas of what's on topic.... discussion about whether there are special lighting considerations inside payload cleanrooms, or maintenance areas for vehicles (UV damages ABS so we tend to avoid a lot of fluoros when lighting our LEGO models... any such considerations for satellites or launchers? The exterior has to stand direct sunlight which is full spectrum, but what about while working on the guts???)

I believe this are sodium vapor but are going to be changed out.

There are no real requirements for cleanroom lights.  Just basic industrial standards.  Contractors bring their own lights for inspection, close in work and solar array checkout.
« Last Edit: 03/16/2017 01:23 PM by Jim »

Offline Jim

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But back in the day, there was the Solar Array Test Building.

https://environmental.ksc.nasa.gov/projects/documents/HABS-Solar.pdf

Offline manoweb

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I believe this are sodium vapor but are going to be changed out.

Is that you in the picture, Jim?

Offline manoweb

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Current home lights LED beats compact fluorescent and 4' tube fluorescent for efficiency. I thought they also beat discharge type which includes high pressure sodium, mercury and HID. Of course gas discharge come in greater total lumens.

Source for your claim? Are you referring for the lumens/W or the lux/W? There is a difference between the total amount of light and the amount of light measured on an area (LED lights are directive). A good domestic lighting uses both direct and indirect light.

Obviously here we are talking about directional lights but again, the ~parabolic mirrors used in a search light light these should be very efficient, so I would not be so sure that LED would fare a better lux/W than these Xenon lights, even if LED that powerful existed in the first place.

My sources: scroll down for relevant data that is lumens/W AND, perhaps more importantly for this thread, lumens per lamp:
https://www.eia.gov/todayinenergy/detail.php?id=9871


Offline Lar

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I believe this are sodium vapor but are going to be changed out.

Is that you in the picture, Jim?

Who else can stand on the ceiling without trying hard and look good doing it??? THAT's how powerful Jim is, and don't you all forget it. [1]

Bump. This is now a separate topic, in the general section, so it's not SpaceX specific. I'd love to hear more about how other pads are lit,
They are lit by the exact same lights.  They are a range resource and shared among all the users.

What about at Kourou? Pleznetsk? (sp?) Chinese launch sites? ... I kind of expect that the DPRK wouldn't light their pads well (electricity costing what it does, lol.... plus maybe harder for spies) .... but everyone else?  This is a topic for all launchpads everywhere... Not just the Cape or Vandy. (I would assume MARS, Vandy, Cape probably all use the same tech but maybe Kodiak is different?)


1 - I know, it's probably an upside down pic.
« Last Edit: 03/16/2017 06:20 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

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