NASA seeks clues to onboard computer actions

Computerworld | FEBRUARY 05, 2003 | DAN VERTON

[Zavien Doombringer]

NASA investigators want to know if adjustments made to the position of the space shuttle Columbia during its last minutes by the vehicle's onboard control computers could have played a role in its breakup during re-entry Feb. 1. In a revised timeline of events released Feb. 3, Ron Dittemore, NASA's space shuttle program manager, said that at 8:59 a.m. EST, Columbia's five onboard computer systems began to detect a significant increase in drag on the vehicle's left wing and ordered two of the shuttle's four yaw jets to fire for 1.5 seconds to compensate for the change.

Investigators aren't sure yet whether the adjustments ordered by the computer played a role in the shuttle's breakup. "It was well within the flight control system's capability to handle the [maneuver]," said Dittemore. "But what is becoming interesting to us now is the rate of change."

While Dittemore acknowledged that NASA may never be able to determine the exact root cause of the crash, he said investigators are now studying all of the data from the launch process as well as the shuttle's flight control systems.

The focus on Columbia's flight control systems could be significant. On Feb. 3, Computerworld reported that Columbia and other space shuttles have a history of computer glitches that have been linked to control systems, including left-wing steering controls (see story).

Although officials said it's too early in the investigation to pin the blame for the crash on the control computers, William Readdy, deputy administrator of NASA, said officials are actively searching for any of the shuttle's five onboard computer systems. Although it's unlikely they survived the crash, he said, the computers have "memory resident in them" that could shed light on the status of the shuttle after communications were lost with ground control.

Each computer's memory stores "telemetry of thousands of parameters that affect the flight of the shuttle," Readdy said.

Columbia and other space shuttles have experienced a series of control computer failures during the past two decades, including one that had a direct link to the spacecraft's left-wing control systems. During a March 1996 return flight, NASA officials discovered a computer circuit problem that controlled steering hardware on Columbia's left wing. The computer circuit was responsible for controlling the spacecraft's left rudder, flaps and other critical landing functions.

Speaking at a news conference prior to Columbia's landing in March 1996, NASA spokesman Rob Navius downplayed the seriousness of the computer problem.

"There are three additional paths of data that are up and running in perfect shape, and there's multiple redundancy that would permit a safe landing," he said. Although Columbia landed without incident that time, NASA officials said the failure was significant enough that had it happened earlier in the flight, the agency would likely have ordered the shuttle home early.

The General Accounting Office, the investigative arm of Congress, has also criticized NASA in the past for relying on the same commercial contractors to develop, test and validate the space shuttle software (see story).

However, Donna Shirley, the former manager of NASA's Mars Exploration Program and the team that built the Sojourner Microrover, said there is no evidence yet that flaws in NASA's software-validation program had anything to do with the disaster.

[Zavien Doombringer]

That's a powerful NERF missle there, I wouldn't want to be hit by that! 500 - 1500mph, it wouldn't matter, something felt it!

[Ditto]

Gemini 8 had to be brought down early because of a stuck-open thruster. In May of 1968, LLRV no. 1 (LLRV was the predecessor to the more advanced LLTV) crashed while being piloted by Neil Armstrong.

If I recall correctly, Armstrong was also the pilot on Gemini 8 who pulled the capsule out of a rapid roll from the stuck thruster only seconds before he would have lost consciousness. He was one hell of a pilot.

[CCWoody]

I am sure the new stuff is much better than the old days. ~ wirestripper

While the technology for controlling systems has moved up an exponential curve, the logic for the systems has not changed much. Consider that Henry Ford, in designing a way to pump coolant around the cylinders of his engine used a type of a feedback control loop to open the thermostat and close it again based upon temperature feedback from the fluid. Of course, I speak only in a gross sense compared to the computer control systems and sensors that the software uses on the shuttle. It really is a marvel that we don't have a continually breaking down Bill Gates variant of an OS software causing all kinds of mischief on the shuttle.

I often find myself in a terminology pit as somebody is always inventing something new and adding some new and fancy name to it.

Woody.

[RightWhale]

Gemini 8 had to be brought down early because of a stuck-open thruster.

They nearly lost that one. The pilots were close to blacking out as the capsule spun up to one revolution per second.

[FReepaholic]

I wonder if they had that camera active for the STS-107 mission? I haven't heard mention of it.

[BraveMan]

The thing I keep tripping on is how thoroughly the chunk of foam disintegrated after the impact with the orbiter.

The chunk of foam appears to jump into a 500+ MPH (Delta V)airstream and, for the most part, remain one piece. That appears to be some pretty tough foam insulation. Only after the strike with the orbiter wing does the chunk turn to dust. There had to be some serious kinetic energy stored in that chunk of foam.

Imagine swinging a baseball bat made out of the stuff, as hard as you can. The speed at the tip of the bat is going to be in the neighborhood of 80-120 MPH, depending on the strength of your arm. Now imagine whacking a piece of Grandma's china during the swing . . .

Now imagine swinging the bat at least four times faster and smacking a tile known to crack from the impact of a quarter dropped from two feet.

Knowing how fragile the tiles are, I am puzzled by NASA's spokespersons wanting to take that event off the table . . .

[cyberaxe]

.....you wouldn't happen to know.....

.....the name of the OS the Shuttle uses.....

.....would you?.....

[Zavien Doombringer]

Windows NT4.0 sp6

JJ :)

[Cold Heat]

I have been fortunate to have done the work that I have, in the area of control systems. My days of writing ladder logic programs are over, but I am still interested in the field.

If I could eventally get my health situation fixed, I might get back into it. I really love the science.

[CCWoody]

I believe it is an in house software custom designed for the space shuttle. But, I can't say with any certainty. I don't think there is any need to fear that moments before the shuttle came apart the blue screen of death was seen on the computer consoles.

[Rain-maker]

Like Landing a ‘Flying Brick’ http://abcnews.go.com/sections/science/DailyNews/shuttle001024.html
It may seem surprising that clouds, wind and rain can prevent an advanced vehicle like the space shuttle from touching down, but Laura Rochon, a NASA spokesperson explains the shuttle has less flexibility when it comes to landing conditions.
     “This vehicle is like a flying brick — once you make the de-orbit burn, the shuttle is committed to land,” she says. “It can’t circle around an airport and wait for better conditions.”

 

Tons of references to the shuttle being a flying brick:

http://www.google.com/search?num=100&hl=en&lr=&ie=UTF-8&oe=UTF-8&as_qdr=all&q=+shuttle+%22flying+brick%22

 

 

NASA doesn't coin terms for AF jets btw.

[Cold Heat]

Now we also must remember that this foam has a hard resin like coating applied, so the falling piece may resemble a cheap biker's helmet instead of a brittle chunk of styrene.

No coating is applied. The stuff forms a skin(microns thin) when it dries.

It is basically the same stuff you buy in a can at the Home Depot for home projects.

[Imnidiot]

Imagine dropping a piece of styrofoam or poly foam out of your car window as you travel 70 mph down the freeway...does the foam fly along side you for awhile or does the wind tear that sucker out of your hands before you get it half out of the window?
I may be an idiot, but I can easily imagine supersonic airpressure slowing that chunk of foam tremendously.
Try this experiment: have a buddy hold up a chunk of foam...drive by at 70 and stick out your arm and let it hit your hand.
When you come out of surgery to repair your arm socket, we'll talk.

[Cold Heat]

Unfortunately it is not that simple. The area where the foam traveled to was in the turbulence and high/low pressure zones between the tank and orbiter.

NASA has studied this before and they seem a bit puzzeled by it as well.

[cyberaxe]

.....thanks guys.....

.....I was afraid it might be.....

.....the same one that a controller manufact. that i rep.....

.....used to advertise as being used by NASA.....

.....on the Space Shuttle!.....

[Zavien Doombringer]

I understand the reasoning, it was a joke. The F-4 was always called the "flying brick" by us mechanics, it wasn't with out saying "goes to prove if you strap powerful enough engines (j-79s) to a brick, it will fly"

[clamboat]

Imagine dropping a piece of styrofoam or poly foam out of your car window as you travel 70 mph down the freeway...does the foam fly along side you for awhile or does the wind tear that sucker out of your hands before you get it half out of the window?

I allowed for that in my posting. I said explicitly that the debris would decellerate, and the shuttle itself was still accellerating, but none of that implies that in the, say, <.5 seconds between the breakoff and impact in the wing that they accumulated a relative velocity of 1500 mph! 150mph, I can easily believe, even 500 mph, perhaps. but no way was the piece of foam moving at 1500 mph relative to the wing when it impacted.

[betty boop]

The word is that Dittemore is on his way out. That's what I hear from people at JSC.

I hope that's not true. I don't see what purpose would be served by making Dittemore a sacrificial goat. (Politics can be that cheap, though, and often is.) He has impressed me with his forthrightness and extraordinary professionalism throughout what must be, for him, a devastating trial at a time of great personal grief. My sense is he's a man of character and integrity.

I've been wondering whether there's any possible way this catastophe could have been the result of a cyberattack. About two weeks ago, the Bank of America national ATM network was taken down by a "worm" whose source, quite interestingly, appears to be untraceable. Could this attack have been a "dress rehearsal" in the lead up to "the main event?"

Thoughts, anyone?

[Zavien Doombringer]

Being in the computer industry now, that thought did cross my mind. However, the shuttle had proprietary software, you would have to write a bug in that code for it to work. then you would have to send on the same radio frequency, which is coded (crypted)...It would be very difficult, but not impossible.