NASA: Foam Probably Not Cause of Shuttle Disaster

Reuters ^ | 2/05/03

[kattracks]

Wed February 5, 2003 05:45 PM ET
CAPE CANAVERAL, Fla. (Reuters) - NASA said on Wednesday a piece of debris that broke loose from the fuel tank shortly after the launch of space shuttle Columbia was likely not the cause of the shuttle's loss and the death of its crew.

The foam debris, about the size of a small suitcase, was captured on video breaking away from the shuttle's external fuel tank shortly after liftoff from Florida. The foam was seen vaporizing after it hit the underside of the orbiter.

NASA shuttle program manager Ron Dittemore, casting doubt on one of the leading theories on the cause of the shuttle's disintegration on Saturday over Texas, said the foam simply was not heavy enough or traveling fast enough to damage the shuttle's heat resistant tiles.

"We're focusing our attention on what we didn't see. We believe there was something else ... there's got to be another reason," Dittemore said during a briefing at the Johnson Space Center in Houston.

Dittemore also said the shuttle's management team did not believe there was any ice under the foam that might have contributed to damage, another theory that had been offered as the root cause of the destruction of NASA's oldest space shuttle and the deaths of the seven astronauts as they returned from a 16-day science mission in space.

[TLBSHOW]

I new you would like it. What are your thoughts since....

After a series of telephone conversations Tuesday afternoon, the photographer had a veteran shuttle mission specialist knocking at his door by dinnertime. Within hours, he was left with a receipt, and his camera was on its way to Houston.

http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2003/02/05/MN192153.DTL

[RS]

I agree, after the fact it's easy to make the call -
besides jumping to conclusions, he bases his accusations on facts unknown at the time.

I wonder what he would have said if the controllers made a call to send up a second "rescue" shuttle and the insulation ripped off that one also ?

[gitmo]

The foam theory is only one of many. There's been an ongoing problem with the left wheel wells, and there have been many examples of significant damage to the tiles from micrometeor impacts.

Why are we so quick to claim a cover-up. Even if there is one, the claims of cover-up are premature.

[X-FID]

2 - that seems like a peculiarly small amount of temp change. I would think that the orbiter as a whole would exhibit much much larger increases in temp, even on surfaces not directly facing the reentry path.

If they used thermocouple's for sensors for example, a "K" type is good for a couple thousand degrees F or more, they are relatively fast in response time, however after those recorded temperatures increased, those thermocouples may have just been vaporized giving the "off scale low" readings.

The sensors also have insulated wires running from them, I don't know of any insulation that can handle those temps.

Off scale low indicates the sensor was gone!

[TLBSHOW]

oh and

Act of God or Terrorist? Which will they choose?

[justshe]

As I've said from the first, I shall wait and see. Too many theories and too many fingerpointers are already forming a parade. NOT a parade I wish to be associated with.

[DugwayDuke]

Wouldn't an impact with an faster moving object (the wing) increase the speed of the impacting object (the foam)?

[dickmc]

Speed of shuttle was 770 feet per second at that point. The foam was going at 770 feet per second up at the point where it fell off. At that point its drag would have slowed it down. The foam did not hit the shuttle wing, the shuttle wing hit the foam.

The NASA analysis assummed a relative speed between the foam and the shuttle wing of 1500 feet per second (if I heard him correctly) according tho the press conference today, and at that speed predicted no damage.

BTW: This all sounds good. But, if this predicted no damage how come the popcorning of the foam from earlier flights did damage the foam??????

Maybe some reporterette will ask tomorrow, but I doubt it.

[TLBSHOW]

What does NASA do act of God which plays into the enemies hands, or Terrorist attack by China as USABLUE says........

or NASA screwed up really bad as I think.

Some really good choices huh?

[Amelia]

Having been several times in situations (with others) where we were reasonably certain our expected lives could be measured in minutes, it's better to know...At least they would have had the chance to say "good-bye" properly, in their own way... To have NOT allowed this... Is beyond cruel.

For all you know, they did, and for all you know, everyone concerned really did think the damage was minimal and they'd return safely - or perhaps that the danger was no more than a normal weekend drive on the freeway.

None of us can guarantee we'll make it home tomorrow, can we?

[SteveH]

One reason I don't think it's ice, is that a core mass did not totally pulverize. This leads me to think it was the shell/surface of the foam. In the video you can see a mass leaving the wing midst the pulverized debris. Ice would have shattered on impact, IMO.

It could be a combination of both, ice formed on foam.

On the object hit hypothesis, the problem developed on the left wing. If the wing is hit in outer space, there would be an impact event. Although rather small, I wonder if it would be noticeable enough to cause a roll and pitch of the shuttle. (A roll goes around the longitudinal axis.) Rolling and pitching is something that is monitored on a constant basis, and any change would be noticed. At some point in time, a corrective thruster activation would have needed to be done, for any object carrying with it some appreciable energy.

I recall NASA being concerned about space junk and micrometeorite hits a few years back. I got the generic impression that someone in NASA was studying it or was assigned to study it and countermeasures (if any). Wonder what NASA has on the detection of object hits. Another thing I recall is that a very small object hitting the shuttle in orbit-- say, the size of a .22 bullet or less-- could cause almost catastrophic damage depending on where it hit. So how small would the object need to be to escape detection and not cause damage but still cause heat shield failure?

I would like to see NASA get asked some specific questions about object impact in orbit detection if they are going to claim this as a possible reason behind the crash.

Also, I think the president has in a sense already given the marching orders that shuttle flights are to resume as quickly as practical. Perhaps the quickest way to do that, cynically, is to claim a possible unknown object hit, and fix the real problem out of the spotlight where hard questions don't need to be asked and answered. In this scenario, the NASA managers are just turning the crank and not really forging ahead on a forthright investigation.

We've seen the drill before, so I guess it would not be the first time or particularly out of the ordinary.

[Light Speed]

Guidance, Navigation and Control Overview GNC software commands effect vehicle control and provide sensor data needed to compute these commands. Flight Control System Hardware Hard-wired to one of eight flight-critical MDMs. Navigational Aids Include IMUS, tacan units, air data probe assemblies, and more. Inertial Measurement Units Consist of an all-attitude, four-gimbal, inertially stabilized platform. Star Trackers Two star tracker units are part of the navigation system. Crewman Optical Alignment Sight Used if IMU alignment is in error more than 1.4 degrees. TACAN Determine slant range and magnetic bearing to ground station. Air Data System Provides information on the movement of the orbiter in the air mass. Microwave Scan Beam Landing System Used during landing phase to determine slant range, azimuth and elevation to landing runway. Radar Altimeter Measure absolute altitude from the orbiter to nearest terrain within beamwidth of orbiter's antennas. Accelerometer Assemblies Sense vehicle acceleration along lateral and vertical axes. Orbiter Rate Gyro Assemblies Used by flight control system to sense roll, pitch and yaw rates during ascent and entry. Solid Rocket Booster Rate Gyro Assemblies Used as feedback to find rate errors from liftoff to SRB separation. Rotational Hand Controller Used by flight crew to gimbal engines and OMS/RCS systems. Translational Hand Controller Used for manual control of translation along the longitudinal, lateral, and vertical axes to control RCS. Control Stick Steering Push Button Light Indicators Indicate control stick mode. Rudder Pedals Command orbiter rotation about the yaw axis by positioning the rudder during atmospheric flight. Speed Brake/Thrust Controller Used during ascent to vary thrust level of main engines; used during entry to control aerodynamic drag. Body Flap Switch Provide manual control for positioning body flap during entry. RHC/Panel Enable/Inhibit Provide signals to GPCs, prohibiting execution of related software commands while RHC is active. Trim Switches Used to move the aerosurfaces in roll, pitch and yaw. Aerosurface Servoamplifiers Receive commands during atmospheric flight, causing aerosurface deflections. Digital Autopilot Composed of several software modules that interpret maneuver commands and generate commands for the appropriate effectors. Rendezvous Thrusting Maneuvers OMS/RCS thrusting periods can be used to correct or modify the orbit as required. Component Locations Black boxes are situated in several locations around the orbiter. -------------------------------------------------------------------------------- Curator: Kim Dismukes | Responsible NASA Official: Catherine Watson | Updated: 04/07/2002

Columbia returned to service, fresh from a year and a half of maintenance and upgrades that have made it better than ever. More than 100 modifications and improvements have been made to make Columbia ready for flight on STS-107. Highlights include a “glass cockpit” with nine full-color, flat-panel displays, reduced power needs, old wire removal, and a user-friendly interface.

STS 109 March 2002....Columbia suffers a systems failure during pre-test cycling prior to de-orbit burn.
Failure occurs in 4 port RCS thruster pack [pitch/yaw/roll]

[bvw]

Ach, I am tired. You're right. And the shuttle itself was accelerating.

[Rockitz]

Good questions! You must be some kinda rocket scientist.

[DugwayDuke]

"NO. Everything depends on the uncompromised integrity of the tiles."

NO. Not really. I had the opportunity to read a Risk Assessment of these tiles today. According to this report a tile burn through, in and of itself, doesn't necessarily doom the shuttle. It depends upon what happens next. A burn through only means that equipment behind that tile will be exposed to the heat load. If there is no critical equipment behind that tile then the effects may not result in a shuttle loss. A burn through could also result in a loss of adjacent tiles which might lead to a widening problem. But, a burn through may or may not cause a catastrophic event.

I fully intended to email this report home but I forgot. I'll do that tomorrow so I can provide a source.

[SteveH]

I am trying to make sense of that. 770 fps shuttle speed at which time the 2.5 lb piece breaks off. Then it hits at 1500 fps? Bullets fly at between 600 and 5000 fps. That would be a big hit and doesn't sound quite right. Also the friction drag would effect speed as the cube of the velocity and I think it would slow down relative to the shuttle but not hit at such a speed...

[barker]

Has it occurred to NASA to simply scratch January off of the launch calendar?

Scrap all January launches and DON'T name any new space vehicles anything that starts with a 'C'.

[ARCADIA]

Act of God or Terrorist? Which will they choose?

Pilot Error

[DugwayDuke]

Whether the 60 degree rise is critical may depend upon the mechanism for heat transport. If the rise is due to conduction, then it may not be critical since that may indicate the temperature of the source of the heat was small, ie, close to the measured temperature. But if the heat transfer mechanism was radiant, then the source temperature might be large.

[DugwayDuke]

Or then again, it might have only picked up a rotational velocity....