Posted on 02/04/2003 1:34:19 AM PST by bonesmccoy
In recent days the popular media has been focusing their attention on an impact event during the launch of STS-107. The impact of External Tank insulation and/or ice with the Orbiter during ascent was initially judged by NASA to be unlikely to cause loss of the vehicle. Obviously, loss of the integrity of the orbiter Thermal Protection System occured in some manner. When Freepers posted the reports of these impacts on the site, I initially discounted the hypothesis. Orbiters had sustained multiple impacts in the past. However, the size of the plume in the last photo gives me pause.
I'd like to offer to FR a few observations on the photos.
1. In this image an object approximately 2-3 feet appears to be between the orbiter and the ET.
2. In this image the object appears to have rotated relative to both the camera and the orbiter. The change in image luminosity could also be due to a change in reflected light from the object. Nevertheless, it suggests that the object is tumbling and nearing the orbiter's leading edge.
It occurs to me that one may be able to estimate the size of the object and make an educated guess regarding the possible mass of the object. Using the data in the video, one can calculate the relative velocity of the object to the orbiter wing. Creating a test scenario is then possible. One can manufacture a test article and fire ET insulation at the right velocity to evaluate impact damage on the test article.
OV-101's port wing could be used as a test stand with RCC and tile attached to mimic the OV-102 design.
The color of the object seems inconsistent with ET insulation. One can judge the ET color by looking at the ET in the still frame. The color of the object seems more consistent with ice or ice covered ET insulation. Even when accounting for variant color hue/saturation in the video, the object clearly has a different color characteristic from ET insulation. If it is ice laden insulation, the mass of the object would be significantly different from ET insulation alone. Since the velocity of the object is constant in a comparison equation, estimating the mass of the object becomes paramount to understanding the kinetic energy involved in the impact with the TPS.
3. In this image the debris impact creates a plume. My observation is that if the plume was composed primarily of ET insulation, the plume should have the color characteristics of ET insulation. This plume has a white color.
Unfortunately, ET insulation is orange/brown in color.
In addition, if the relative density of the ET insulation is known, one can quantify the colorimetric properties of the plume to disintegrating ET insulation upon impact.
Using the test article experiment model, engineers should fire at the same velocity an estimated mass of ET insulation (similar to the object seen in the still frame) at the test article. The plume should be measured colorimetrically. By comparing this experimental plume to the photographic evidence from the launch, one may be able to quantify the amount of ET insulation in the photograph above.
4. In this photo, the plume spreads from the aft of the orbiter's port wing. This plume does not appear to be the color of ET insulation. It appears to be white.
This white color could be the color of ice particles at high altitude.
On the other hand, the composition of TPS tiles under the orbiter wings is primarily a low-density silica.
In the photo above, you can see a cross section of orbiter TPS tile. The black color of the tile is merely a coating. The interior of the tile is a white, low-density, silica ceramic.
Been thinking about the glove theory.
I have a hypothesis.......Could it be that the portion of the glove adjacent to the Gear Well is burned out due to the tile strike, and the rest is still intact but collapsing a few inches like a domino line.
The Gear door theory could still be correct. The two latches are right there.
Tile damage, tile loss, door damage and subsequent hole burned into surface in front of door and involving the door as it spread back. Then the undermining of the glove supports in front of it causing RCC to come off. Tire failure, pyros go off, gear drops, craft yaws out of control.
Back later!
Been thinking about the glove theory.
I have a hypothesis.......Could it be that the portion of the glove adjacent to the Gear Well is burned out due to the tile strike, and the rest is still intact but collapsing a few inches like a domino line.
The Gear door theory could still be correct. The two latches are right there.
Tile damage, tile loss, door damage and subsequent hole burned into surface in front of door and involving the door as it spread back. Then the undermining of the glove supports in front of it causing RCC to come off. Tire failure, pyros go off, gear drops, craft yaws out of control.
Back later!
WASHINGTON -- A NASA engineer weighed the possibility of a "catastrophic" failure resulting from extreme heat on the shuttle Columbia's tires despite assurances days earlier that possible damage to insulating tiles near the landing gear wouldn't imperil the crew.
In internal e-mails released by NASA on Wednesday, one safety engineer, Robert H. Daugherty, warned that extreme temperatures during a fiery descent could cause the wheel to fail and the tire to burst inside Columbia's wheel well.
"It seems to me that with that much carnage in the wheel well, something could get screwed up enough to prevent deployment and then you are in a world of hurt," Daugherty wrote to officials at Johnson Space Center. He added that such an internal blast "would almost certainly blow the door off the hinges or at least send it out into the slip stream -- catastrophic."
WASHINGTON -- A NASA engineer weighed the possibility of a "catastrophic" failure resulting from extreme heat on the shuttle Columbia's tires despite assurances days earlier that possible damage to insulating tiles near the landing gear wouldn't imperil the crew.
In internal e-mails released by NASA on Wednesday, one safety engineer, Robert H. Daugherty, warned that extreme temperatures during a fiery descent could cause the wheel to fail and the tire to burst inside Columbia's wheel well.
"It seems to me that with that much carnage in the wheel well, something could get screwed up enough to prevent deployment and then you are in a world of hurt," Daugherty wrote to officials at Johnson Space Center. He added that such an internal blast "would almost certainly blow the door off the hinges or at least send it out into the slip stream -- catastrophic."
WASHINGTON -- A NASA engineer weighed the possibility of a "catastrophic" failure resulting from extreme heat on the shuttle Columbia's tires despite assurances days earlier that possible damage to insulating tiles near the landing gear wouldn't imperil the crew.
In internal e-mails released by NASA on Wednesday, one safety engineer, Robert H. Daugherty, warned that extreme temperatures during a fiery descent could cause the wheel to fail and the tire to burst inside Columbia's wheel well.
"It seems to me that with that much carnage in the wheel well, something could get screwed up enough to prevent deployment and then you are in a world of hurt," Daugherty wrote to officials at Johnson Space Center. He added that such an internal blast "would almost certainly blow the door off the hinges or at least send it out into the slip stream -- catastrophic."
Trio Took Shuttle Photo With Equipment
By LESLIE HOFFMAN
ASSOCIATED PRESS
ALBUQUERQUE, N.M. (AP) -
The shadowy, closely-analyzed photo of space shuttle Columbia's underside was not snapped with cutting-edge military equipment, but by three researchers playing around with an old computer and an ordinary telescope in their free time, officials said Wednesday.
The grainy photo was made Feb. 1 at the Starfire Optical Range at Kirtland Air Force Base and released Friday by NASA. It shows what appears to be a suspicious bulge on the shuttle's wing shortly before it broke apart.
But contrary to reports last week, the photo was not snapped by one of Starfire's extraordinarily powerful telescopes, which are designed to spy on enemy satellites and detect incoming missiles.
Instead, it was taken by Starfire Optical Range engineers who, in their free time, had rigged up a device using a commercially available 3 1/2-inch telescope and an 11-year-old Macintosh computer, the researchers said. The telescope was surplus laboratory equipment, kept in a cabinet at the Starfire range.
"We were not asked by NASA to do this," said Robert Fugate, the optical range's technical director. "There was no official project or tasking to do this. The people who work here are geeks. This was an opportunity to look at a rapidly moving object and try to take a picture of it. That's really all it was."
The researchers, Maj. Robert Johnson, Rick Cleis, and Roger Petty, said Wednesday they wanted to set the record straight about the image, since its grainy quality had raised questions among those familiar with the Starfire range's capabilities. They said they used none of the technology the Starfire range is famous for.
"This is the blurriest picture we've ever taken of anything, and this is the one that makes the front page of the newspapers," Johnson said.
The men said they realized their photo's significance about 10 minutes after it was taken, after a family member called them to say the shuttle had been lost.
The shuttle's breakup also was captured on video by two Dutch air force pilots training near Fort Hood in central Texas. The Apache helicopter was about 100 feet from the ground when the aircraft's video camera filmed the shuttle.
"This camera is more powerful than others" that have captured footage of the shuttle, said Maj. Matt Garner, a public affairs officer at Fort Hood. "It has the exact time, down to the second, along with the direction the camera is looking."
ABC aired the black and white video on its evening news show Wednesday night. It shows the shuttle broken into several pieces streaking across the sky.
The video has been turned over to NASA and will be analyzed, said Johnson Space Center spokesman Alan Buis.
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