Posted on 02/02/2003 6:35:58 PM PST by TLBSHOW
Astronauts doomed from the start
THE seven astronauts on space shuttle Columbia may have been doomed in the first moments after they were shot into space 16 days ago.
NASA officials are investigating whether loose foam from an external tank that struck Columbia's left wing during takeoff contributed to its disintegration under the stress of re-entering the Earth's atmosphere one of the most dangerous parts of any shuttle mission. The last words between mission control at Houston and shuttle commander Rick Husband gave no clue of impending disaster:
Mission control: "Columbia, Houston, we see your tyre pressure messages and we did not copy your last."
Cdr Husband: "Roger, but . . ." No more was heard.
The homeward-bound space shuttle broke up in flames and trails of smoke and vapour over Texas yesterday, killing all seven astronauts aboard.
The disaster struck 16 minutes before Columbia, the oldest in the shuttle fleet at 22 years, was due to land at Cape Canaveral in Florida. Echoing the tragedy of space shuttle Challenger, which stunned the world 17 years last week, Columbia exploded at an altitude of about 63km as it was travelling 18 times the speed of sound.
The explosion scattered debris and human remains across hundreds of square kilometres in Texas and Louisiana and shook houses in the area around Nacogdoches, Texas.
Police in Hemphill, eastern Texas, said human remains believed to be from the crew of Columbia had been recovered.
"I can confirm human remains from the space shuttle Columbia have been found in the debris," Hemphill police spokeswoman Karen Steele said, declining to elaborate.
A burnt torso and thigh bone were found on a Texan country road while elsewhere a scorched helmet and arm patch from one of the space suits were discovered.
In a televised address to the nation, an emotional President George W. Bush paid homage to the astronauts, saying, "The crew of the shuttle Columbia did not return safely to earth but we can pray that they are safely home".
The sparse information NASA had yesterday seemed to point to failures on the craft's left side.
Sensors on the shuttle's left wing and in the left wheel gear detected a sudden temperature increase or failure minutes before the vehicle exploded 63km over Texas as it flew at more than 20,000km/h.
NASA had concluded only two days ago there was no serious damage to the tiles, but was uncertain last night.
"As we look at that now in hindsight we cannot discount that there might be a connection," stunned shuttle manager Ron Dittemore said.
Investigators have all but ruled out terrorism as a cause because the shuttle's high altitude and extreme speed effectively put it out of range of an attack from the ground.
Officials are focusing on the extent of damage sustained during take-off.
Experts said many other malfunctions could have destroyed the shuttle during re-entry, when a cocoon of hot plasma envelops the spacecraft.
Columbia's underside and the leading edges of its wings would have been subjected to some of the highest temperatures during re-entry up to 1650C as friction from air rushing by heated its surface, experts said.
During this critical period, computers control the shuttle's angle of descent as it flies with its nose pointed about 40 degrees upward; the slightest deviation from the ideal orientation can expose underprotected parts of the vessel, causing it to burn up.
The shuttle's chief defences against an inferno are about 28,000 heat-resistant tiles attached to its vulnerable aluminium exterior. Experts have worried about the tiles' tendency to break off during flights since the earliest days of experimental test flights.
Relatives of the astronauts six Americans and an Israeli watched in horror while waiting at Cape Canaveral's VIP area to welcome their loved ones.
Residents in Texas, Louisiana and Alabama reported hearing the explosion as the shuttle fell apart at more than 18 times the speed of sound.
Bob Molter from Palestine, Texas, said he had seen the shuttle break up in the sky.
"There was a big boom that shook the house for more than a minute, and I went outside because I thought there had been a train accident," he said.
"I looked up and saw the trails of smoke zig-zagging, going across the sky."
Thousand of pieces of debris landed over vast areas of Texas and Louisiana which experts said may take years to find. People were warned not to touch any wreckage because it might be contaminated with toxic propellants.
President George W. Bush rushed to the White House from where he described the disaster in a televised address as a national tragedy.
"The Columbia is lost. There are no survivors," he said, before later ordering all flags be flown at half-mast.
The crew, six of whom were married and five of whom had children, were relatively inexperienced. Only three had flown in space before.
NASA has ruled out human error.
Well that is one way of saying it. But that is not a very correct anology. Here, this trip is made not so frequently, but the times it is in the ground, tests, re-painr, upgrades keep happening. They want it to look like new everytime it takes off.
If I recall the news, the crew was in communication with Houston until 9:00 EST, at which time, I believe they were over North (maybe northeast) Texas, you are claiming that the shuttle was suffering catasthropic events at re-entry without the crew, or ground control noticing it?
Or could it be that the people who reported seeing this in Vegas are caught up in the moment?
"The fact that the left wing was damaged at lift off."
No Todd, that's an assumption. The fact is than on film, something appears to have struck the left wing, then disintegrate. No one knows exactly what that object may have been, and at this point, what damage that may have caused has not been ascertained. We'll have to wait until the results of the investigation to find out.
"The fact someone in Utah saw things breaking off it there and the fact NASA says it heated up in 60 seconds."
Todd, I can have sworn testimony delivered to you from thousands of people from Miami who claim that they saw the face of Jesus in an avocado pit.
Someone in Utah Todd?
I think the largest bit of debris from the shuttle found so far is less than twelve feet long, and not quite as wide. What you offer up as "proof" is that someone in Utah saw details on an object that size, roughly two hundred plus thousand feet above his or her head, traveling in a cloud of smoke at 18 times the speed of sound?
Have you ever seen a vehicle at re-entry? Would you know the difference hbetween a normal re-entry, and a catastropic one if you saw it?
"The fact that a person in California says he saw problems there as it went over."
It was going even faster and higher here, but you have another Hawkeye up for proof.
The shuttle enters the atmosphere surrounded by a fireball, that's why the tiles are in place, to protect the shuttle from the fire.
A big, red ball of fire in the sky to some.
"That is how I base my opinion as a fact as to what happend to this space shuttle.
Do you have any idea of just how incredibly ridiculous that statement is?
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FIELD JOURNAL FIELD JOURNAL FIELD JOURNAL FIELD JOURNAL
STS-87 rolled to a stop; the mission was complete! That statement would be true for the flight of the Columbia, however a new mission began when the wheels of the Columbia came to a stop -- the post flight inspections. My division is responsible for the overall analysis of these inspections and we insure that all changes made, due to these inspections, do not affect other areas that may jeopardize the flight-worthiness of the shuttle. This division does not focus on one specific area, but analyzes all information and ensures that all aspects are kept in balance.
Immediately after the Columbia rolled to a stop, the inspection crews began the process of the post flight inspection. As soon as the orbiter was approached, light spots in the tiles were observed indicating that there had been significant damage to the tiles. The tiles do a fantastic job of repelling heat, however they are very fragile and susceptible to impact damage. Damage numbering up to forty tiles is considered normal on each mission due to ice dropping off of the external tank (ET) and plume re-circulation causing this debris to impact with the tiles. But the extent of damage at the conclusion of this mission was not "normal."
The pattern of hits did not follow aerodynamic expectations, and the number, size and severity of hits were abnormal. Three hundred and eight hits were counted during the inspection, one-hundred and thirty two (132) were greater than one inch. Some of the hits measured fifteen (15) inches long with depths measuring up to one and one-half (1 1/2) inches. Considering that the depth of the tile is two (2) inches, a 75% penetration depth had been reached. Over one hundred (100) tiles have been removed from the Columbia because they were irreparable. The inspection revealed the damage, now the "detective process" began.
During the STS-87 mission, there was a change made on the external tank. Because of NASA's goal to use environmentally friendly products, a new method of "foaming" the external tank had been used for this mission and the STS-86 mission. It is suspected that large amounts of foam separated from the external tank and impacted the orbiter. This caused significant damage to the protective tiles of the orbiter. Foam cause damage to a ceramic tile?! That seems unlikely, however when that foam is combined with a flight velocity between speeds of MACH two to MACH four, it becomes a projectile with incredible damage potential. The big question? At what phase of the flight did it happen and what changes need to be made to correct this for future missions? I will explain the entire process.
The questions that needed to be answered were:
At this point, virtually every inch of the orbiter was inspected and all hits were documented and mapped to aid in visualizing the damage. Maps were constructed of the lower surface, the left and right surfaces and the top surface of the orbiter. At this point, a "fault tree" was created. The fault tree provides a systematic approach in considering all possibilities of what may have happened. Everything that is on the fault tree is considered to be legitimate until it is totally ruled out. Some of the considerations were where the damage occurred -- in the OPF, in the VAB, or on the pad before launch. These were quickly eliminated because an inspection at T-3 ("t minus three") hours takes place on each mission and everything was normal.
After these and many other considerations were eliminated, the focus was placed on the ascent, orbit and re-entry phase of the mission. Because of the fore and aft flow characteristics of the damage sites, and the angle of penetration, the ascent phase seemed most likely. The orbit phase of flight was eliminated because the characteristics of these types of hits (most likely meteorites or space debris) occur in a random pattern and direction. Re-entry was eliminated because the "glazing and re-glassifying" of the tiles due to heat upon re-entry (a normal process) indicated that the damage had occurred prior to this phase. The fault-tree was now pointing to the ascent phase.
The pictures that were taken by cameras mounted in the orbiter umbilical began to give the first clues. These cameras are designed to turn on during the solid rocket booster (SRB) separation, and turn off after the separation is complete, thereby recording the event. This process occurs once again when the external tank separates from the orbiter. The initial review of these photographs did not reveal any obvious damage to the external tank. No foam missing, no "divots" (holes) and no material loss. Everything appeared normal.
The SRBs were then focused on for the answers. After inspection of the SRBs, no clues were found. In fact, the solid rocket boosters looked to be in great condition. Where to now? The external tank photographs were magnified and reviewed once again. This time some material loss was noted, but not in a significant degree. The attention was now focused on the crew cabin cameras. These cameras gave more of a side view of the external tank as it tumbled back to Earth. These photographs revealed massive material loss on a side of the external tank that could not be viewed by the umbilical cameras!
Where are we now? One of the questions had now been answered. The ascent phase of flight was when the damage occurred. With the information provided by the photography and the mapped flow of damage, a logical reason could be established as to "what" happened. It was determined that during the ascent, the foam separation from the external tank was carried by the aerodynamic flow and pelted the nose of the orbiter and cascaded aft from that point. Once again, this foam was carried in a relative air-stream between MACH two and MACH 4!
Now the big question -- why? The evidence of this conclusion has now been forwarded to Marshall Space Flight Center (MSFC) because this is the design center for the external tank. MSFC will pursue the cause of damage. Here are some descriptions of some of the considerations:
As this investigation continues, I am very comfortable that the questions will be answered and the solutions applied. In fact, some of the solutions are already in progress. At present the foam on the sides of the tank is being sanded down to the nominal minimum thickness. This removes the outer surface, which is tougher than the foam core, and lessens the amount of foam that can separate and hit the orbiter.
It looks BIG and RED. I've seen one.
That statement means nothing.
Shuttle launches and re-entry are strenuous situations for the vehicle. "Wear and tear" (including some loss of tiles) has occurred on each and every launch and is expected.
Jael's post DOES refer to "wear and tear" on flight STS-87 (December 23, l997) that was greater than previously experienced. (It also makes passing mention of similar, albeit lesser, damage that occurred on the previous flight, STS-86.)
In comparison, the tragedy we experienced with Columbia was flight STS-107.
Rather than becoming frantic over a single report of "wear and tear" suffered 20 flights ago, I'd be more interested in seeing a tabulation of the comparable inspections that occurred with the intervening 20 flights. It would have been with the benefit of that additional experience that the experts would have been basing their judgement whether any potential damage caused by the foam at liftoff was within "normally" acceptable wear & tear parameters.
First, the orbiter must be maneuvered into the proper position. This is crucial to a safe landing.
When a mission is finished and the shuttle is halfway around the world from the landing site (Kennedy Space Center, Edwards Air Force Base), mission control gives the command to come home, which prompts the crew to:
Photo courtesy NASA Artist's concept of a shuttle re-entry |
Because it is moving at about 17,000 mph (28,000 km/h), the orbiter will hit air molecules and build up heat from friction (approximately 3000 degrees F, or 1650 degrees C). The orbiter is covered with ceramic insulating materials designed to protect it from this heat. The materials include:
To TLBSHOW: Oops! You're right. I don't know how I got thought you made the comment I was answering. Sorry.
To TheDon: Please see #185.
To ALL: Sorry about the double post (185 & 186). I've been in the hospital with my daughter for the last week and am very tired and don't remember doing it.
Vile. Absolutely vile.
You are a bigot.
Did you think I wasn't still here, Todd? You are disgusting.
"Wear and tear" is one thing and yes, a certain amount of tile loss is normal but I was under the impression that this chunk of insulation colliding with the wing at Mach2+ was an unusual event.
We will just have to agree to disagree on this. I say it was something that should have been checked out to the greatest extent possible rather than subjected to speculative risk analysis. The stakes were too high.
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