Could the Shuttle have been by Lightning during re-entry?

[SiriMurthy]

On 2003-02-04 19:42, Donnie B. wrote:
Hale, I think the question was referring to the possibility of the shuttle being struck by space junk on orbit or during reentry - not the public being struck by shuttle debris.

Thanks, Donnie. Yes, that was my question: the Space Shuttle being struck by space debris, not the public on ground.

Sorry, I didn't make that clear earlier.

[SiriMurthy]

On 2003-02-04 19:41, Donnie B. wrote:
Another observer (an astronomer) saw several glowing objects break off the shuttle over California.

Over California? That would be before the reentry, correct?

Geographically, at what point (over which geographic location) does the shuttle would be entering the thinnest layers of out atmosphere?

[Donnie B.]

It would have been relatively early in the reentry.

In fact, the shuttles normally fly within the upper reaches of the atmosphere while on orbit. On the nightside, a faint glow is often seen around the tail and OMS pods, due to collisions with oxygen atoms.

Naturally, as the orbiter descends, it encounters increasing atmospheric density. It would certainly be experiencing significant heating over California on the way to a Florida landing. The peak heating would have been over Texas, just where the main breakup occurred.

[SpacedOut]

On 2003-02-04 19:33, nebularain wrote:
Do the shuttles normally leave a vapor trail behind on re-entry?

In watching one of the videos, it looked like there might have been an explosion before some pieces broke off. Was that mere appearance, or would the breaking apart of the shuttle created some things to explode?

Answer to #1 – yes-it is a plasma vapor trail caused by the superheated atmosphere. IRRC it’s the same thing you see behind a meteor. (Its been a while since I’ve read BA’s book)

Can’t really help you with question 2 – I just thought that when Columbia broke up there was a bloom in the plasma trail. Don’t know if the forces involved would have caused an explosion.

[fixed some formatting]


<font size=-1>[ This Message was edited by: SpacedOut on 2003-02-04 21:45 ]</font>

[SiriMurthy]

Thanks for the response. Now, a couple of questions:

>>...around the tail and OMS pods, due
1. What is OMS? (pardon my ignorance)

>>...collisions with oxygen atoms.
2. How would these Oxygen atoms "stay" there? I main, why don't they "fly" away into the depths of space - vacuum?

[ToSeek]

On 2003-02-05 13:48, SiriMurthy wrote:
Thanks for the response. Now, a couple of questions:

>>...around the tail and OMS pods, due
1. What is OMS? (pardon my ignorance)

Orbital Maneuvering System. Small(er) rockets at the back of the shuttle, above the main engines. Used to adjust the orbit as needed.

[John Kierein]

http://elf.gi.alaska.edu/
This site says that sprites are visible to at least 95 kilometers height. That's about 300,000 ft. They may extend higher but there may not be enough air for them be visible above that.

[Donnie B.]

On 2003-02-05 13:48, SiriMurthy wrote:
Thanks for the response. Now, a couple of questions:

>>...around the tail and OMS pods, due
1. What is OMS? (pardon my ignorance)

>>...collisions with oxygen atoms.
2. How would these Oxygen atoms "stay" there? I main, why don't they "fly" away into the depths of space - vacuum?

1) Orbital Maneuvering System. (ToSeek is exactly right.) Those are the smaller rocket motors that sit "above" the main engines; the two big bulges at the tail are there to house the OMS engines. You often see those bulges in pictures of the cargo bay taken from inside the crew compartment.

2) The same reason the rest of the atmosphere stays put: gravity. To escape completely, a particle has to reach escape velocity (something around 25000 mi/hr). Some O2 atoms may occasionally do so at those altitudes through collisions with particles of the solar wind or cosmic rays, but most don't. So there they stay.

The atmosphere doesn't have a "top"... it just gets thinner and thinner the farther out you go. In practical terms, it's a near-perfect vacuum at the altitude where the shuttle operates, but go twice as high and it's an even better vacuum. And at some point, it becomes as tenuous as the solar wind, and then I suppose you can say you're out of the Earth's atmosphere and into the Sun's.

[SiriMurthy]

...the two big bulges at the tail are there to house the OMS engines.

Of course! [img]/phpBB/images/smiles/icon_biggrin.gif[/img] I always wondered what those "bulges" were, even though I was aware of the rocket nozzles sticking out of those areas, it never occurred that these "bulges" house the engines.

OK, now I know what OMS stands for. Thanks.

2) The same reason the rest of the atmosphere stays put: gravity. To escape completely, a particle has to reach escape velocity (something around 25000 mi/hr). Some O2 atoms may occasionally do so at those altitudes through collisions with particles of the solar wind or cosmic rays, but most don't. So there they stay.

Excellent! Thanks for the education. I guess that's the reason why atmosphere didn't stay on Mars - it doesn't have enough mass to have the gravity that is enough to keep the "air" (I mean atmosphere) on its surface.

The atmosphere doesn't have a "top"... it just gets thinner and thinner the farther out you go. In practical terms, it's a near-perfect vacuum at the altitude where the shuttle operates, but go twice as high and it's an even better vacuum. And at some point, it becomes as tenuous as the solar wind, and then I suppose you can say you're out of the Earth's atmosphere and into the Sun's.

What would you say the level of vacuum is at the height the Shuttle operates - how many times is this better then the best vacuum we can produce on Earth?

Thanks.

[Donnie B.]

Oh, you would have to go and get technical on me... [img]/phpBB/images/smiles/icon_smile.gif[/img]

I don't have numbers for you, but if memory serves, the vacuum at typical shuttle altitudes is better than a laboratory vacuum, but not astoundingly so. We can make a pretty good vacuum on a small scale, but not in "large quantity" [img]/phpBB/images/smiles/icon_smile.gif[/img]

Still, at 100 miles up, it's practically a pressure cooker compared to the really hard vacuum out between the galaxies - one atom per cubic meter or so out there, on average.

[SiriMurthy]

Oh, you would have to go and get technical on me... [img]/phpBB/images/smiles/icon_smile.gif[/img]
Hey, you are the Bad Master. I am just a Bad Apprentice [img]/phpBB/images/smiles/icon_biggrin.gif[/img]

We can make a pretty good vacuum on a small scale, but not in "large quantity"
I like the way you put it. We "make" good vacuum. What do you make again - oh it is nothing. We make pretty good nothing. [img]/phpBB/images/smiles/icon_smile.gif[/img]

one atom per cubic meter or so out there, on average.
Yup, that's what I was looking for.

Thanks a bunch.

[DaveOlden]

On 2003-02-03 13:46, nebularain wrote:
From article posted above

...And a San Francisco amateur astronomer has shown The Chronicle -- but not released publicly -- a photograph of a vivid, lightning-like discharge apparently crossing through the contrail's left side. The image is one of five snapped in sequence at 5:53 a.m., when the shuttle's sensors began to fail.

So, what are the speculations on what this man(?) saw?

This is from the SF Chronicle February 2

Early in the article:

... taken with a Nikon-880 digital camera on a tripod, reveal what..

The Nikon 880 is indeed a digital camera.
Now, toward the end of the article...

"... but it showed up clear and bright on the film when I developed it," the photographer said.

It struck me as very odd that a photographer, especially an amateur astronomer who would be very familiar with his own camera, would make this mistake.

[Kizarvexis]

On 2003-02-06 03:49, DaveOlden wrote:
"... but it showed up clear and bright on the film when I developed it," the photographer said.

It struck me as very odd that a photographer, especially an amateur astronomer who would be very familiar with his own camera, would make this mistake.

I'm betting that he used 'developed' for the lack of a better term. Or he had a brain lock on 'download' and went with 'developed' as it is close in a general sense, i.e. got the pics out of the camera.

Kizarvexis

[DaveOlden]

On 2003-02-06 05:06, Kizarvexis wrote:

On 2003-02-06 03:49, DaveOlden wrote:
"... but it showed up clear and bright on the film when I developed it," the photographer said.

It struck me as very odd that a photographer, especially an amateur astronomer who would be very familiar with his own camera, would make this mistake.

I'm betting that he used 'developed' for the lack of a better term. Or he had a brain lock on 'download' and went with 'developed' as it is close in a general sense, i.e. got the pics out of the camera.

Kizarvexis

I might have been a little too reactive there, since I do say "filmmaking" while I'm editing digital video. Some terminology is pretty stubborn. You have a good point there.

I certainly did not mean to discount his claim; how could I? I haven't even seen the image, and I have no reason to doubt him.

I am eager to see what it is that caused that light.

[John Kierein]

Here's an update.
http://www.sfgate.com/cgi-bin/articl...06/MN22145.DTL
They still haven't connected to the storms to the west of Hawaii. The plasma trail went right over these. The plasma trail persists and makes a good path to the orbiter even over that distance. Ignorasphere.

[SiriMurthy]

On 2003-02-06 10:07, John Kierein wrote:
Here's an update.
http://www.sfgate.com/cgi-bin/articl...06/MN22145.DTL
They still haven't connected to the storms to the west of Hawaii. The plasma trail went right over these. The plasma trail persists and makes a good path to the orbiter even over that distance. Ignorasphere.

Wow! I thought you were just making up the term "Ignorasphere" until I followed the link. Pretty deep stuff. John, you may be right about lightning all along [img]/phpBB/images/smiles/icon_confused.gif[/img]

[John Kierein]

There are explosive charges in the wheel well in case the door gets stuck. The temperatures recorded were not sufficient to set them off, according to the program manager. But could a lightning strike have done it?

[DALeffler]

I dunno Mr. Kierein...

Apollo 13 got hit directly by lightning at least twice in stage 1 ascent and had all kinds of explosive charges on board...

On the other hand, Gus Grissom always said (I think), "It just blew..."

Might be interesting to compare the track of MR-4 to Columbia. Hmm.

Doug.

(Corrected sp...)

<font size=-1>[ This Message was edited by: DALeffler on 2003-02-06 20:34 ]</font>

[ToSeek]

On 2003-02-06 20:33, DALeffler wrote:
I dunno Mr. Kierein...

Apollo 13 got hit directly by lightning at least twice in stage 1 ascent and had all kinds of explosive charges on board...

Apollo 12, actually, though that doesn't affect your point.

[Hale_Bopp]

Actually, I mentioned the Apollo 12 lightning strike a bit back [img]/phpBB/images/smiles/icon_smile.gif[/img]

Actually, unknown at the time, a rocket can spawn lightning strikes. The University of Florida studies lightning by lauching small rockets in an attempt to stimulate strikes in predictable places. After all, you can't study them if you don't know where they will be.

I don't think Columbia would have stimulate a lightning strike. After all, the external skin of Columbia is cermic tile, not a metal conductor like a Saturn V or the small rockets used in research.

The U of Florida Lightning Laboratory page is at http://www.lightning.ece.ufl.edu/

Rob

[Squink]

I don't think Columbia would have stimulate a lightning strike.

That nice trail of conductive plasma stretching out behind it might.

[John Kierein]

I think red sprites are much stronger than ground lightning. I think the really strong red sprite lightning initiated the NASA Standard Initiators. They are only spec'd to survive around 50,000 volts or so. And these were near the surface in the wheel wells.
I am somewhat familiar with the NSI's. We used them a lot on CRRES which was originally planned for a Shuttle launch. NASA should do a test in the configuration of these. Somebody tell 'em if they haven't already figured this out.

[John Kierein]

They're looking. Infrasonics.
http://www.sfgate.com/cgi-bin/articl...7/MN200326.DTL

[David Hall]

I believe the "lightning catcher" rockets used to study lightning always have ground wires attached to them, to create an easy path to the ground and force the lightning strikes to follow the wire instead.

Now, as for the idea that electrical discharge "followed" the shuttle along it's plasma trail, I think it's a very highly speculative idea. Not exactly impossible, but I think it's one that I'd put way down on the list of possible causes, only to be looked at if absolutely nothing else makes sense.

Sprites, elfs, and such do deserve study of course, but it's premature to assign behaviors to them when we know so little about their true natures yet.

[Thumper]

On 2003-02-07 13:04, David Hall wrote:
I believe the "lightning catcher" rockets used to study lightning always have ground wires attached to them, to create an easy path to the ground and force the lightning strikes to follow the wire instead.

You are correct. I saw a show on this some time back. The rockets were fired during a thunderstorm and had ground wires attached.

To avoid the chance that the lightning strike could follow the path of the wiring of the igniter clear into the control room, launch was initiated pneumatically with non-conductive material. I remember hearing the countdown and then the guy grabbed a rubber tube and blew in it.

(spelling)

<font size=-1>[ This Message was edited by: Thumper on 2003-02-07 13:45 ]</font>

[John Kierein]

Just like the wires on the rocket, the lightning follows the plasma trail. A friend of mine thinks that the reason lightning takes a jagged path is because it may be partially following the ionization trails of cosmic rays.

[DStahl]

But I don't understand: if lightning-catcher rockets are connected to an earth ground and therefore attract lightning, where's the earth ground connection to the shuttle's plasma trail? Mind you, my father was an electrician and part of my adolescent rebellion consisted of mentally blocking all understanding of things electric, so I'm probably missing something obvious.

[SpacedOut]

On 2003-02-08 17:56, DStahl wrote:
But I don't understand: if lightning-catcher rockets are connected to an earth ground and therefore attract lightning, where's the earth ground connection to the shuttle's plasma trail? Mind you, my father was an electrician and part of my adolescent rebellion consisted of mentally blocking all understanding of things electric, so I'm probably missing something obvious.

Electricity is essentially the flow of electrons. When lightning bolt strikes the Earth, it is essentially seeking a source of electrons. However, the Earth isn’t the only source of electrons – in cloud to cloud lighting (IIRC - the most common form of lightning) one of the clouds acts as the “ground” or pool of electrons. The way to look at the plasma trail is that it could act as a conductor to a “ground” source just as the wire trailing from lighting catcher rockets connect the rocket to the Earth.

[DStahl]

It still needs a ground, though, doesn't it; or more properly perhaps, an electric potential gradient like that which develops between different regions of thunderclouds? As El Sordo said, "Faltan caballos"--it lacks horses.

OK, I think I see what you are saying: suppose the Shuttle passed through a region of negative potential and into one of positive potential; the conductive plasma trail could then act as a path from one region to the other, and the Shuttle would potentially [<font size=-1>Ha! Get it?</font>] be in the circuit. I might have thought that in the rarified upper extremes of the atsmosphere such charged areas would much less likely than lower down, where things like moving water droplets can build up immense electrostatic charges. But then again, red sprites have been observed up there, so SOMETHING is going on.

Though, as someone noted, since we don't understand red sprites very well all this is possibly quite irrelevant.

<font size=-1>[ This Message was edited by: DStahl on 2003-02-09 00:02 ]</font>

<font size=-1>[ This Message was edited by: DStahl on 2003-02-09 04:11 ]</font>

[DStahl]

carolyn posted an article from the SF Chronical about the possiblility of an atomospheric discharge causing or contributing to the Columbia disaster. Here's a link to the Feb 7 article she mentions, and here's another link to an article of Feb 8 that casts some doubt as to whether this could be a cause after all. Finally, here's yet another Chronicle story, datelined Feb 7, giving some background on sprites, blue jets, and elves.

Thanks to carolyn for bringing these up in her post in the Against the Mainstream section.