Shuttle Tried to Right Itself Near the End, Tapes Reveal

OUSTON, Feb. 16 — The scrambled data from the final moments of the shuttle Columbia's flight showed that two thrusters fired briefly in a last-ditch effort to regain control.

These scraps of flight information, gleaned from data received in the 32 seconds after mission control lost radio contact, suggest that the Columbia astronauts might have had time to develop a sense of the shuttle's plight. But NASA spokesmen would not speculate on the meaning of the data, which were released on Saturday by the accident investigation board led by retired Adm. Harold W. Gehman Jr.

Investigators have been searching for clues in the "mostly ragged, mostly unintelligible data" from the final 32 seconds of the flight, said Rob Navius, a NASA spokesman.

The shuttle had been fighting drag on its left wing before losing control on Feb. 1 over Texas, and NASA previously announced that two of the shuttle's jets had fired before communication was lost. Ron D. Dittemore, the shuttle program manager, said in a Feb. 5 briefing that the data from that point showed that "more and more flight control muscle is being added to keep the vehicle pointed straight ahead and eventually that flight control muscle is going to run out; you only have so much."

"And when it does, you eventually will lose control," Mr. Dittemore said. The reason for the drag is still unexplained, but the new information shows that the craft was putting still more muscle into its effort to correct its course.

The shuttle's jets are part of its reaction-control system, which is made up of 44 jets fueled by blending two chemicals that ignite upon contact with each other, nitrogen tetroxide and monomethyl hydrazine. During the shuttle's entry into the atmosphere, the craft is guided by its onboard computers, and the pilot takes over for landing.

The extra data was retrieved from a little-known form of communication on space shuttles. In addition to having communication gear that sends its signals earthward, shuttles have an antenna that points up. These signals are received by Tracking Data and Relay System Satellites, which relay signals from lower orbiting satellites, and from space shuttles, back to the Earth.

Such information comes through even when other transmissions are disrupted by re-entry.

The shuttle investigation board also said the workers sorting debris at the Kennedy Space Center had also discovered one of five general-purpose computers from Columbia. An earlier announcement of the discovery of one of the same computers, which are used to control the shuttle's functions, proved to be mistaken. The computers are not like the black box used in general aviation, and do not even have hard drives to store information. In its status report, the board said that the recovered computer had lost its battery, which keeps data alive in some chips, so "investigators held out little hope of extracting additional information."

Alan Buis, a NASA spokesman, said, "Without the battery attached, the RAM, the random access memory, would be immediately erased." Each of the computers, which are made by IBM, is 7.62 inches high, 10.2 inches wide and 19.55 inches long. Each weighs 57 pounds.

The search for other pieces of debris and the clues that they might hold is continuing. Attempts to find debris in New Mexico have been unsuccessful. The shuttle board has said that the westernmost piece of confirmed shuttle debris recovered is a tile found about 20 miles west of Fort Worth.

A main engine turbo pump was recovered near Fort Polk, La. The 800-pound pump hit the ground with such force that it was found 14 feet below the surface.

NASA said that the mission management team did not meet today and would not meet on Monday and that the Gehman commission had no formal meetings scheduled during that time. Members of the board have returned to Houston after visiting the Kennedy Space Center in Florida, the Marshall Space Flight Center in Huntsville, Ala., and the Michoud Assembly Facility near New Orleans last week.

... Columbia's flight showed that two thrusters fired briefly in a last-ditch effort to regain control.These scraps of flight information, gleaned from data received in the 32 seconds after mission control lost radio contact, ...

Any help for the analysis?

2 posted on 02/17/2003 1:15:59 PM PST by brityank (The more I learn about the Constitution, the more I realise this Government is UNconstitutional.)

Not much, I believe they are referring to the aft thrusters. It happened as the craft was losing control.

Another report I read over the weekend says that the right rear two thrusters fired a few seconds prior to loss of contact and that the left front thrusters were actually the ones firing after the loss of contact. I believe that this report must be referring to the left front thrusters.

4 posted on 02/17/2003 1:27:58 PM PST by PatriotGames (AOOHGA! AOOHGA! CLEAR THE BRIDGE! DIVE! DIVE! WHOOSH!)

I'll try to find it, but I thought that the front thrusters had also fired trying to correct the yaw from the left-wing drag. I do remember that both of the Right rear thrusters fired, but I don't quite understand how they would swing the left side forward and mitigate the excess drag.

5 posted on 02/17/2003 1:28:11 PM PST by brityank (The more I learn about the Constitution, the more I realise this Government is UNconstitutional.)

> Any help for the analysis?

Well, if the NYT were in the news business, instead of
the propaganda biz, they might have reported a couple
of simple things like:
* which thrusters
* commanded by computer or by crew

If NASA got this much out of the 32 seconds, they might
yet get more.

The primary FR thread on the disaster is:
http://www.freerepublic.com/focus/news/835531

Yes, the front left thrusters were firing like crazy. The right rears came online near the end to assist in correcting the yaw.

There are a number of video shots which showed that the ship (over Arizona) had already slewed almost 90-degrees sidewise, and was descending with its left-most wing first. This is odd, since the drag was the greatest on this wing. You would think it would have caused the shuttle to rotate around the other way, and lead with its right wing. At any rate, at Mach 18.5 the ship's vertical stabilizer could not withstand such pressures (taking the full blast against it's side) long before snapping off.

8 posted on 02/17/2003 1:32:37 PM PST by Paul Ross (From the State Looking Forward to Global Warming! Let's Drown France!)

A main engine turbo pump was recovered near Fort Polk, La. The 800-pound pump hit the ground with such force that it was found 14 feet below the surface.

With as much debris that fell with no one hit or major damage to property, it gives lie to the overcrowding claims of the looney environMENTALists!

9 posted on 02/17/2003 1:32:45 PM PST by brityank (The more I learn about the Constitution, the more I realise this Government is UNconstitutional.)

The thrusters referred to are the thrusters that are used to manuever the shuttle while on orbit. There are several on the the orbiter. I believe there are twenty four on the aft and twelve on the forward portion of the orbiter. I also don't understand why the right side thrusters would fire to counteract drag on the left side of the orbiter..... Any help?

If NASA got this much out of the 32 seconds, they might yet get more.

Nothing that tells them something that they do not already know. It just shows broken up data on the last moments of structural integrity as it broke up.

Right rear tail thrusters were used in combination with the left front nose thrusters to turn the axis back to where it was supposed to be. When they failed to correct the axis, the side of the shuttle was exposed to 3000 degree heat and aero forces that it was not meant to handle.

Ooops! Right side thrusters would counter a drag on the left side of the orbiter if it were the right hand outboard thrusters that fired..... These thrusters are positoned on each side of the orbiter to allow for thrust in three directions... Up, OUTBOARD and down... My bet is the outboard thrusters that fired to counter the left hand wing drag.....

BTW, for some further clarification, the rudder of a airplane normally does this task, however, the rudder is not helpfull at over 200,000 feet. That is why the thrusters are used.

... outboard thrusters that fired ...

Thanks; that makes sense now.

15 posted on 02/17/2003 1:51:00 PM PST by brityank (The more I learn about the Constitution, the more I realise this Government is UNconstitutional.)

Those angles were done through the normal course of landing. They are called roll reversals.

Yes, the left wing was damaged and when second turn was initiated, the wing got worse.

I donot know what AZ pics you refer to that show the shuttle skewed. The data tranmitted by the shuttle at that time showed everthing normal as to the flight path.

90-degrees orientation of the shuttle athwart its flight vector is not a normal roll reversal. The S-Curves programmed into the flight computers don't call for anything approach such a radical yaw.

17 posted on 02/17/2003 2:11:25 PM PST by Paul Ross (From the State Looking Forward to Global Warming! Let's Drown France!)

The first roll occured as they were approaching California. It was 80 degrees. The roll reversal occured at 13:56.15 GMT and initiated over Utah/NM. The craft never got into a 90 degree attitude until destruction.

There's been a lot of talk here on FR about that video clip, and we've determined that what appears to be the shuttle hurtling sideways across the sky is actually an image distortion that is common in certain camcorders when the object is out of focus.

Some folks who really knew their stuff about video cameras helped clear that one up.

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.