Posted on 02/01/2003 4:25:45 PM PST by Sub-Driver
Columbia's Problems Began on Left Wing By THE ASSOCIATED PRESS
Filed at 6:56 p.m. ET
CAPE CANAVERAL, Fla. (AP) -- Investigators trying to figure out what destroyed space shuttle Columbia immediately focused on the left wing and the possibility that its thermal tiles were damaged far more seriously than NASA realized by a piece of debris during liftoff.
Just a little over a minute into Columbia's launch Jan. 16, a chunk of insulating foam peeled away from the external fuel tank and smacked into the ship's left wing.
On Saturday, that same wing started exhibiting sensor failures and other problems 23 minutes before Columbia was scheduled to touch down. With just 16 minutes remaining before landing, the shuttle disintegrated over Texas.
Just a day earlier, on Friday, NASA's lead flight director, Leroy Cain, had declared the launch-day incident to be absolutely no reason for concern. An extensive engineering analysis had concluded that any damage to Columbia's thermal tiles would be minor.
``As we look at that now in hindsight ... we can't discount that there might be a connection,'' shuttle manager Ron Dittemore said on Saturday, hours after the tragedy. ``But we have to caution you and ourselves that we can't rush to judgment on it because there are a lot of things in this business that look like the smoking gun but turn out not even to be close.''
The shuttle has more than 20,000 thermal tiles to protect it from the extreme heat of re-entry into the atmosphere. The black, white or gray tiles are made of a carbon composite or silica-glass fibers and are attached to the shuttle with silicone adhesive.
If a spaceship has loose, damaged or missing tiles, that can change the aerodynamics of the ship and warp or melt the underlying aluminum airframe, causing nearby tiles to peel off in a chain reaction.
If the tiles start stripping off in large numbers or in crucial spots, a spacecraft can overheat, break up and plunge to Earth in a shower of hot metal, much like Russia's Mir space station did in 2001.
Dittemore said that the disaster could have been caused instead by a structural failure of some sort. He did not elaborate.
As for other possibilities, however, NASA said that until the problems with the wing were noticed, everything else appeared to be performing fine.
NASA officials said, for example, that the shuttle was in the proper position when it re-entered the atmosphere on autopilot. Re-entry at too steep an angle can cause a spaceship to burn up.
Law enforcement authorities said was no indication of terrorism; at an altitude of 39 miles, the shuttle was out of range of any surface-to-air missile, one senior government official said.
If the liftoff damage was to blame, the shuttle and its crew of seven may well have been doomed from the very start of the mission.
Dittemore said there was nothing that the astronauts could have done in orbit to fix damaged thermal tiles and nothing that flight controllers could have done to safely bring home a severely scarred shuttle, given the extreme temperatures of re-entry.
The shuttle broke apart while being exposed to the peak temperature of 3,000 degrees on the leading edge of the wings, while traveling at 12,500 mph, or 18 times the speed of sound.
A California Institute of Technology astronomer Anthony Beasley, reported seeing a trail of fiery debris behind the shuttle over California, with one piece clearly backing away and giving off its own light before slowly fading and falling. Dittemore was unaware of the sighting and did not want to speculate on it.
If thermal tiles were being ripped off the wing, that would have created drag and the shuttle would have started tilting from the ideal angle of attack. That could have caused the ship to overheat and disintegrate.
Dittemore said that even if the astronauts had gone out on an emergency spacewalk, there was no way a spacewalker could have safely checked under the wings, which bear the brunt of heat re-entry and have reinforced protection.
Even if they did find damage, there was nothing the crew could have done to fix it, he said.
``There's nothing that we can do about tile damage once we get to orbit,'' Dittemore said. ``We can't minimize the heating to the point that it would somehow not require a tile. So once you get to orbit, you're there and you have your tile insulation and that's all you have for protection on the way home from the extreme thermal heating during re-entry.''
The shuttle was not equipped with its 50-foot robot arm because it was not needed during this laboratory research mission, and so the astronauts did not have the option of using the arm's cameras to get a look at the damage.
NASA did not request help in trying to observe the damaged area with ground telescopes or satellites, in part because it did not believe the pictures would be useful, Dittemore.
Long-distance pictures did not help flight controllers when they wanted to see the tail of space shuttle Discovery during John Glenn's flight in 1998; the door for the drag-chute compartment had fallen off seconds after liftoff.
It was the second time in just four months that a piece of fuel-tank foam came off during a shuttle liftoff. In October, Atlantis lost a piece of foam that ended up striking the aft skirt of one of its solid-fuel booster rockets. At the time, the damage was thought to be superficial.
Dittemore said this second occurrence ``is certainly a signal to our team that something has changed.''
Nothing is impossible! Have you ever seen a lineman up a pole in a cocoon on a cold day? There are ultrastrong adherents that can be prepared in a warm ready-box.
I assume that this warm ready box or cocoon you are describing has air inside it. Air can be heated. The astronaut would be working in a vacuum.
”A little neglect may breed great mischief. For want of a nail the shoe was lost; for want of a shoe the horse was lost; and for want of a horse the rider was lost.”
Plus, I find it hard to believe that a lab would not have lots of parts that could be jettisoned without damaging the spaceworthiness of the shuttle.
Sometimes, yeah: there's nothing that can be done. But I'm gonna look hard for something to do before I make that fatalistic conclusion. It's pretty clear that this scenario was written off.
In the absence of definitive proof at this point, I'm gonna call it a night.
Yep. I've also seen them under a tent for three days reparing a phone line that I dug up with a backhoe. It was pretty (the phone line); every color wire you've ever imagined - it looked like a tree root when it came up.
Meanwhile, it was in an area that the telco had "posted" (no flags in the area) as having no lines... accidents do happen.
From This Thread
A review of the records of the STS-86 records revealed that a change to the type of foam was used on the external tank. This event is significant because the pattern of damage on this flight was similar to STS-87 but to a much lesser degree. The reason for the change in the type of foam is due to the desire of NASA to use "environmentally friendly" materials in the space program. Freon was used in the production of the previous foam. This method was eliminated in favor of foam that did not require freon for its production. MSFC is investigating the consideration that some characteristics of the new foam may not be known for the ascent environment."
at post 54.
Actually, the dynamic load is only about 1.5g. Engineers actually have a pretty good handle on aircraft structures under such modest loads. Also the initial sensor troubles happened 7 minutes before breakup.
Tiles are the great unknown. I'd suspect them first. Secondly, not knowing the systems, I'd wonder if there were any internal systems that could self-destruct with catastrophic results.
On the record.
No, OReilly, they could not inspect the tiles.
And, no, they could not lighten the load.
Furthermore, OReilly, had they BEEN able to inspect the tiles and discovered a gaping hole in the tiles down to the aluminum skin sufficiently large to guaranty burn up on re-entry, NOTHING could have been done to save their lives.
The Delta V (their ability to change velocity and/or vector) on board the Columbia is severely limited. They literally did NOT HAVE ENOUGH to change the shape of their orbit so that it would reach the additional 115 miles altitude of the orbit of the ISS... much less change the pitch of its orbit to match. The laws of physics are unbreakable.
As for waiting around for a 'resecue mission', that also is not possible. The Shuttle carries supplies, especially oxygen, in excess of the planned mission paramaters... but not that much, several days at best. Supply problems exist for systems other than O2: CO2 scrubbers, water supplies, etc., all have a limited operation time. It takes WEEKS and most likely MONTHS, to prepare another launch. The astronauts would be dead long before a rescue expedition could be mounted.
If they have discovered tile damage by your hypothetical inspection EVA, they are presented with these choices:
1: They cross their fingers and try to come home. If the tiles are OK or the re-entry heat does not break through, they are home, safe. If the tiles are not OK, they are dead, quickly.
2: They wait for rescue. In about five days, the oxygen in the shuttle runs out. They are dead... guaranteed... but it will be a long lingering death.
At least by trying re-entry they had a chance.
The load was the Space Habitat/Laboratory that FILLS the cargo bay.
Assuming there are "lots of parts that could be jettisoned", getting them OUT is a major problem. The Lab is not designed for space access... and each cycling of the air-lock wastes air.
Another problem is that "jettisoning" things in space is not as easy as it sounds. Tossing them outside the shuttle only puts them in orbit WITH THE SHUTTLE. The Space jetsam may collide with the shuttle as it burns for re-entry, further damaging the tiles. In addition, everything left up there becomes dangerous to future missions ... think space garbage moving at many times faster than bullets hitting a future shuttle in a similar orbits.
Another problem. The dynamic balance of the shuttle would be adversely affected by removing objects of unknown mass and ejecting them. The calculations ... the PRECISE CALCULATIONS... needed to accurately plan your orbital changes require specific knowledge of the mass being accellerated or decellerated. You may reach the vicinity of the ISS but be several miles short... or several MPH too fast or slow... and no longer have the Delta V to change anything.
As I said before... It IS Rocket Science.
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