[AP SCOOP] Space Shuttle Columbia Will Be Visible In San Francisco Area (6AM Pacific)

nasa

[leadpenny]

Space Shuttle Columbia is in a decent for the Kennedy Space Center in Florida and will pass over the San Francisco Area around 6:00 AM Pacific Time. Route will take the Shuttle over Las Vegas, Flagstaff, etc. NASA has still not decided which runway will be used. Landing will be at 9:16 AM Eastern.

[Jael]

Just wanted to say welcome.

[Dr. Eckleburg]

On one of these threads I read that both military land cameras and space satellites routinely photograph the Shuttle's entire journey.

Certainly makes sense. NASA knows much more than it's telling.

It's odd to listen to every TV talking-head and newspaper say the problem most likely was due to the take-off tile damage, while every NASA employee from Dittemore on down maintains that's not realistic, and something else caused the problem.

IMO, regardless of the truth, NASA will publicly lay the blame on the errant tiles, and move on.

[Timesink]

Welcome to FR, Mike!

[MikeFromBelgium]

Thank-you.

It's interesting to read how you react to this event out there.

[MikeFromBelgium]

Here are 4 pictures of the debris that have been published by CNN :

We also know that this piece of foam measures 20 by 16 by 6 inches and weighed 2.67 pounds. What we see on the 4th picture is that the debris blew up completely. Thus, we can assume that, whatever the angle it came, its total kinetic energy has been transmitted to the wing tiles. Does anyone knows what is the speed of the camera who took the pictures above ? With this additional information, we could easily calculate the velocity of the debris and its kinetic energy when it hits the wing. This would help guessing wether it was damaging or not (and see if NASA was right in their assumptions...) To me, those things are not so complicated to calculate. If someone here can tell me what was this camera speed (Nbr of images / sec), I will provide the detailed engineering calculation.

[Ispy4u]

Another thread sourced this camera's speed in excess of 100 frames per second.

That would explain exactly why no one could see this damage occur during launch.

[Tax-chick]

Cute! Time will tell ...

[DoughtyOne]

Along the same lines, I've been amazed that no terrorist state claimed responsibility. Hezballah, al Qaeda, the Talliban, Saddam Hussein, you name it, you'd think one of them would have found this an impossible situation not to claim credit for.

[leadpenny]

This morning I heard Don Imus, on his radio show from New York, (MFB, the Don Imus Program is the best radio show in America) repeat a shuttle speed of 1500 MPH when the foam or foam/ice hit the wing. By my calculations that would be 2200 f.p.s. There could have been considerable damage.

BTW, my comment about the Don Imus Program could ignite some "Flames." In case you are not familiar with "Flaming," it is a friendly tradition here on FreeRepublic.

[Dr. Eckleburg]

Thanks for your info. Please ping me when/if you get some stats.

[McGruff]

Looks like IMUS was a little low:

Investigators searching for clues to Columbia's loss are focusing on a 2 1/2-pound, 20-inch chunk of foam insulation that fell from the shuttle's external tank moments after liftoff and stuck the underside of the wing, possibly damaging the tiles. The shuttle was traveling at 2 1/2 times the speed of sound at the time, or just over 1,900 mph.

from this article here.

[leadpenny]

That puts it at approx. 2800 fps. As I remember that is about the muzzle velocity of the average high powered rifle. Anything solid in that foam and it could do some real damage.

[MikeFromBelgium]

Thank-you for your data.

post 309 : A shuttle velocity of 1500 mph after 80 seconds seems logical. If we take a constant acceleration of 3g, which is the maximum they take, we get exactly 1463 mph. On the other hand 1900 mph (post 311) seems too high.

But the absolute velocity of the spacecraft does not matter much. What is important, to assess the magnitude of the shock is the relative velocity with the foam piece. This is why, I find it more interesting to calculate from the camera speed.

Regarding that, 100 frames per seconds (post 306) seems reasonable. I would have guessed they use a faster camera but Ok, let’s take it so.

If they used a faster camera, this would lead to a higher relative debris velocity. But on the other hand, if we assume 100 frames/sec, we are on the safe side.

Ok, let’s go :

First of all, please allow me to convert everything in metric units :

Foam piece weight : 2.67 pounds = 1.2 Kg
Foam piece dimension : 20x10x6 inches = 50x25.4x15.2 cm
Foam piece volume : 1200 cubic inches = 19.7 dm3
Foam piece density : 0.07 Kg/dm3
Shuttle length : 37.23 meters
Wingspan : 23.79 meters
Shuttle velocity : 2400 km/h = 666 m/s
Camera speed : 100 frames/sec
Time between each frame : 10 ms

If we look at the pictures, we wee that :

Picture 1 : The debris is just crossing past the shuttle nose
Picture 2 : The debris is somewhere between the nose and the middle of the wing
Picture 3 : The debris has hit the wing and is blown already.

With the small sketch below, we see that the debris travelled approximately 19 meters during the time of 2 frames, that is 20 ms.

Thus, the debris velocity relative to the shuttle was approximately 950 m/s.

Now, there is something wrong here : We have seen above that the shuttle speed after 80 seconds in the flight should be around 666 m/s. We cannot have the foam piece running faster toward the shuttle than the shuttle velocity itself !

Are we sure of the camera speed ? Isn't it 50 frames/sec instead ?

In any case, this would mean that, when the debris hit the wing it was already completely decelerated on its way from the top of the tank. And it was a still object in the sky. Which is indeed the worse case assumption, we can hardly believe that the debris was already falling down to earth.

Thus, let assume the debris velocity equal to 666 m/s.

Please allow me to have already some though about this figure. You certainly remember the painful events late last year in Virginia with this sniper killing innocents. He made it with a .223 Remington caliber (know in Europe as 5.56 NATO, which is the same). 666 m/s is roughly 2/3 of the velocity of a .223 Rem bullet at muzzle exit !

Whould you like to receive a 2.66 pound piece of foam on the head at that speed ? Whoops !

Now, let’s figure out what it means in terms of energy.

The kinetic energy in joule is obtained by multiplying the weight by the square of the velocity divided by two.

That is, the kinetic energy of the debris is around 266,133 joule.

Now let’s compare it to the height we should launch this debris to obtain the same energy :

The potential energy is obtained by multiplying the weight by the earth acceleration by the height.

Thus, we get 22,607 meters (266,133 / 9.81 / 1.2).

In other units, it means that, without air friction, we would have to launch this debris from 22.6 km or 74,000 feet ! This is just CRAZY.

Now, frankly, as an engineer, if I had to sit in the meeting room with NASA people to discuss this, I would certainly have said that there is a chance for the damage being significant…

Of course, I would be pleased if anyone reading me criticize or correct me if I am wrong.

[creativetoo]

Does anyone remember a similar incident with the shuttle Endeavor? If I remember correctly it was the launch prior to the Columbia one. A piece of insulation, from the external fuel tank, came off and hit the shuttle during the launch. It hit one of the main engine casings and left a dent in it.
Now...if it could leave a dent in a metal engine casing it could surely have damaged some of the shuttle tiles enough to cause its breakup on re-entry.
I've been trying to find confirmation of this online but haven't been able to find anything about damage that was found after any of the shuttles returned.
Does anyone else remember hearing or reading about this?

[MikeFromBelgium]

What you mention about this dent on the main engine casing is interesting indeed. I haven't read anything about other damages with insulation.

Today in the news, Nasa seems to say that they just cannot believe this debris is the (unique) cause of the accident. They say that the debris velocity was around 750 feet/s which is less than what I have calculated with very little data (an maybe inacurate).

Yet, 750 feet/s is still very fast (the velocity of shotshell ammunition). What is worrying me is that the piece of foam has turned completely into dust after the collision. This must have produced a huge vibration on the wing to achieve that.

[bvw]

What I've seen posted on FR is the following: 96 frames per second, but the photos you are looking at are imaging averages of 17 frames.

Analysis has been done on other threads too ...

• http://www.freerepublic.com/focus/news/836736/posts, NASA: Foam Probably Not Cause of Shuttle Disaster
• http://www.freerepublic.com/focus/news/835531/posts, Observation on TPS damage on Orbiter

[MikeFromBelgium]

Thank-you for the info. I'll have a look at it.

I just found an article in Mercury news that is also discusses on another thread title FOAM HAS PLAGUED NASA FOR 5 YEARS. the article can be found at http://www.bayarea.com/mld/mercurynews/news/5100794.htm).

Selected extracts :

"...Engineers typically find some damage to the orbiter's 24,000 ceramic tiles after missions, averaging about 40 ``hits.''"

"...NASA engineers who examined Columbia after a 1997 flight found 308 hits"

"...An investigation traced much of the damage to a ``massive material loss on the side of the external tank"

"...132 hits were larger than an inch in diameter, and some slashes were as long as 15 inches. More critically, some penetrated three- quarters of the way into the two-inch deep tiles, close to the orbiter's aluminum skin"

"...when that foam is combined with a flight velocity between speeds of Mach 2 to Mach 4, it becomes a projectile with incredible damage potential"

"...the 1997 mission, STS-87, was the first to use a new method of ``foaming'' the tanks, one designed to address NASA's goal of using environmentally friendly products"

"...the hits to Columbia on that 1997 mission ... forced NASA to replace nearly 11 times more damaged tiles than it had after a previous mission that had used Freon-based foam"

"...In 1999, the Southwest Research Institute ... fired insulating foam fragments from a compressed-gas gun into thermal tiles and recorded the results with digital cameras. After the Columbia crash, NASA asked the institute not to release those results."

[bvw]

A few other goodies to look into too. That big fat External Tank, which the foam is sprayed onto. These resuable tanks are different -- there seem to be three models, and maybe six tanks. Recent shuttles have used a lightweight model -- possible that the lighter weight, means a more flexible skin and thus that the foam would have better mechanical affinity -- the foam flexes, the skin flexes. However this last flight used an older heavier tank, foam flexes, skin doesn't -- seperation.

Freeper John Jamieson and others are tracking down shuttle weights. John believes this shuttle, with the space hab, would be the heaviest shuttle ever. He suggests that it might have a 30% higher heat load to shed on reentry. (That weight also impacts descent angle, and thus may affect control response.)

Another: This was a January launch, air is denser -- more reentry heating. Ice more likely to form at launch.

Another: Freeper _Jim notes that Columbia's wing leading edge construction differs from other shuttles. Perhaps that is why Columbia seems to have a higher rate of tile damage on prior flights. Also may be more fragile.

Another: Air-flow, mechanical surface vibrations during launch may have had significantly different and new characteristics, due to heaver tank, rebuilt shuttle, heavy shuttle.

[McGruff]

I copied some of your recollections of that day from another thread to here. I hope you don't mind.

"It looked like a big fireball. I assumed this was normal because of heating from reentry.. I have no idea if the shuttle itself was actually "on fire".

Something strange happened when the Columbia was about 3/4 of the way across the horizon.
What I saw looked exactly like what the fella from St. George UT. taped.(I think the UT tape was from St George.)

Some have described it as a flash or a puff. It looked to me like someone turned the "lights" off for split second. The "fireball" seemed to dim, then brighten back up immediately.

The Columbia left a large white contrail. I did not notice if it became enlarged when the "flash" occurred as some eyewitness's in Vegas have said."

[McGruff]

I copied these recollections of yours from another thread since you were one of the original posters to this thread. Hope you don't mind.

We had just come in from watching the shuttle pass overhead, and I realize now that what we saw was the craft breaking up. About 30-45 seconds after we came in into the house we heard one or two loud booms. My first thought was that a transformer in one of the neighborhood's electrical boxes had blown up... that's happened before and it will rattle the garage door a bit. I've seen the shuttle's approach before over North Texas and have never heard a sonic boom - it's just too high... it couldn't have been the shuttle. But at 8:15, when NASA TV was long overdue to show the landing approach, we just knew that something was wrong.

As Columbia passed overhead, we saw it get shredded by unimaginable forces. It was falling like a rock, out of control. Yesterday was a tough day.