[meteorite-list] Re: Credit Card-Sized Fragment Of Columbia Found In California?

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:25 2004
Message-ID: <200302052347.PAA14416_at_zagami.jpl.nasa.gov>

>"... in order for the debris to have any chance of traveling in
>the correct direction, it would have to have come off while
>Columbia was still over the western Pacific. But if a tile
>(or something else with a high drag coefficient) came off at
>this point, it would still have travelled ballistically along
>with the Shuttle since the altitude at this point was over
.50 miles. There's practically no atmosphere to speak of,
>and you're still well above the jet stream.

At an altitude of 50 miles over the Pacific, the shuttle tiles
have already heated up, and the shuttle is performing S-turns
to slow down. I think you also have to factor in the
tremendous speed the shuttle is traveling, which is Mach 25
over the Pacific, and being slowed down by the atmosphere.
Even though there atmosphere is very tenuous at these high
altitudes, there are enough air molecules to affect anything
traveling at hypervelocity speeds.

Here's a couple of items I've extracted from Columbia's
timeline.


- 8:44 am: The shuttle begins the "entry interface," its nose raised at a
40-degree angle so that the ceramic tiles comprising the shuttle's
underbelly heat shield are positioned to take the full force of
frictional heat as it enters thicker atmosphere. The tiles begin to heat up.

- 8:46 am: Columbia, now at an altitude of 61 miles (102 km), is set to land
in 30 minutes. It will cross over California, Nevada, New Mexico,
Arizona, Texas, the Gulf of Mexico off the Louisiana coast and, finally,
Florida.

- 8:49 am: Columbia begins a series of gentle side-to-side turns designed
to lower its speed. The first of these is to the right.

- 8:52 am: Columbia crosses the California coast. Houston control registers
a slight temperature variation in the left landing gear housing. Three
hydraulic thermal sensors are reading temperature gains of 40 to 60 degrees
Fahrenheit (eight to 15 degrees Celsius).

- 8:53 am: A fourth sensor in the left wing signals a rise in temperature.

- 8:54 am: A increase in temperature of 60 degrees F (15 degrees C) is
registered in the shuttle's fuselage over the left wing.

- 8:55 am: Columbia is over the southern Nevada desert.

- 8:56 am: Columbia is over northern Arizona.

- 8:57 am: Over New Mexico, the shuttle -- still on autopilot -- begins a
left turn to reduce its speed. Mission control in Houston loses
transmissions from the left wing temperature sensors.

- 8:58 am: An unexplained drag on its left flank puts Columbia into a
leftward roll, and a trim roll stabilizer automatically kicks in to try to
compensate.

- 8:59 am: The on-board computer attempts to compensate further by
activating two yaw jet thrusters. At an altitude of 38 miles (61 km) and a
speed of 13,000 miles (21,000 km) per hour, Columbia enters the skies over
Texas. The last recorded radio transmission from Houston: "Columbia, this
is Houston. We see your tire pressure messages and we did not copy your
last."

After a moment, Commander Rick Husband replies: "Roger, buh ..."

After a brief crackling noise, contact is lost.

- 9:00 am: With all radio contact lost, Houston tracks the shuttle on radar.
Witnesses on the ground report seeing the craft disintegrate into several
pieces, trailed by a long plume of white smoke.

- 9:16 am: At the shuttle's scheduled landing time, NASA activates its
contingency plan.


Ron Baalke
Received on Wed 05 Feb 2003 06:47:14 PM PST