Posted on 02/06/2003 9:45:33 AM PST by 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.
The problem with software is that if you have code to deal with unusual situations (like unusual drag on one wing), that code might not ever get exercised in real life until something goes somewhat wrong.
And if there's a bug in that section of code, it may turn a "somewhat wrong" situation into a "catastrophicly wrong" situation. I would take a good hard look at the possibility that unusual drag (or loss/corruption of sensor input) may have caused the computer to overcorrect at Mach 20 (with disasterous results).
That one video didn't show the shuttle sideways, as many assumed, it showed the shape of the camera aperture during an out-of-focus period. Your other points are good, though.
Yes, EEprom and PROM,s were used. However, a basic computer that was off the shelf at the time could do the same. It was much too expensive compared to the 500 dollar price of a PLC.
I wonder if this means the jets overcompensated which could have caused the orbiter to travel left wing first as some of us saw in a disputed video capture.
.....banging my head trying to teach end users.....
.....used to using gang-clocks, relays, and the such.....
.....how to do the same thing.....
.....with "puters", logic statements and veri-speed drives.....
It turned out to be a mostly insurmountable task.
The company subsequently went belly up when the bills caught up with them, but I was making progress before I told them to shove it!
It may be an optical illusion, or a trick of the camera in seeing an apparent yawing movement perpendicular to the line of flight, I don't know. But that coupled with the initial speculation (just that) of a control system problem makes me think he got out of alignment in yaw, then went into a spin. Once the less-protected portions of the fuselage were exposed to the friction, it'd be done for. They did see that thermal anomoly along the one side. Again, does that reflect the root cause or a further symptom of an earlier problem...?
Your code setpoints should not allow for an overcorrection.
Interesting, some people here on FR have been rather emotional and at times rude in his defense.
Do you know if he was on the bubble before the Columbia tragedy?
And if there's a bug in that section of code, it may turn a "somewhat wrong" situation into a "catastrophicly wrong" situation. I would take a good hard look at the possibility that unusual drag (or loss/corruption of sensor input) may have caused the computer to overcorrect at Mach 20 (with disasterous results).
Very well said. I'm a programmer, and we've had applications out in the field which suddenly turned up nasty bugs after over a DECADE of proper operation, due to what we jokingly call "the moon is full and it's a tuesday on a leap year" bugs.
These are the ones that only manifest themselves when a rare set of circumstances combine.
I can easily see something like that happening in the Columbia disaster -- a bug or poor design decision in an ancient piece of code which never rose itself from slumber until the very first time a high-drag-on-the-left situation ever occurred.
I don't know. I didn't get that impression. I'll ask.
I was told that there was damage to one of the SRB's by falling "foam/ice" two shuttle missions back. That after it was recovered one of the SRB's was dented at the spot where the material hit. Someone emailed me privately and told me I was wrong and I asked them if it was another mission. They did not respond.
I understand (secondhand again) that there were people calling for the shuttle's to be grounded after this other "foam/ice?" event. That did not happen so it's Dittemore's backside if that's the case and this turns out to be true.
Unfortunately in the real world, there's sometimes a disasterous difference between "should not" and "does not"
Especially if you had some “help.”
My husband B and I have been speculating about the cause of the disaster every night since it happened. Early on, both of us tended to discount the foam-hitting-the-tiles theory. B has two pet hypotheses: (1) the shuttle was impacted by space debris; (2) the foam hit the structure that mates the shuttle to the main booster rocket in such a way that, when the time came for the shuttle to be released, one or more of its four point contacts did not timely release, and the resultant stresses on the body of the craft may have propagated to the hatch door that is close by; and the hatch door later failed, springing open on re-entry.
B doesn’t even want to hear my pet hypothesis – it’s so “wacky” he doesn’t even want to go there! And he’s probably right about that. But – I can’t stop thinking about it. It’s a result of a process of “connecting dots” and perceiving the pattern that emerges; then asking the question, cui bono? – who would benefit from this?
I hope you won’t mind if I share this, Zavien Doombringer. I just want to get it off my chest, then I’ll shut up. And folks can call me just plain nutz if they want to.
Plunging in: A whole lot of the “dots” I’ve been connecting lately have little PRC flags sprouting on them. Just let me describe the dots, in no particular time order nor ranked by relative importance:
(1) There have been stories circulating lately that are being credited in the Third World to the effect that the American Moon landings were elaborate hoaxes. The source seems to be coming from inside PRC. Now PRC recently announced that it’s got a space program going, first stop, Moon. To call the Americans “liars,” and then to show them “inept” (e.g., the loss of Columbia), is to discredit us as the preeminent leader of space technology and exploration in the world.
Plus, there may be a more immediate side benefit – the loss of Columbia and her crew could be expected to injure American morale at a particularly critical time, as President Bush tries to lead a coalition to disarm Saddam.
(2) PRC sits on the U.N. Security Council, where they have been openly opposing the Bush Administration’s position on Iraq. The interesting thing is that Iraqi defectors have stated that Chinese engineers helped Saddam construct the secret bunkers where Saddam is said to be hiding his stuff. If true, there is no way the PRC government can be unaware of this. Yet, have they stepped forward with information about these bunkers – to share this critical information to aid UNSCOM, whose further activities PRC is on record as saying they would like to see extended indefinitely? (Then why not strengthen their ability to succeed by naming known inspection targets?)
(3) Iraq is a client state of the PRC, and so for that matter is North Korea (DPRK). DPRK has apparently been a technology-transfer conduit to Saddam, with particular regard to missile technology and (perhaps) its nuclear program.
(4) DPRK is going “whoopy” on us at a very critical juncture – making nuclear threats against us just when we’re preparing to go to war with another PRC client state. This wouldn’t be the first time that DPRK has acted as a “proxy” for Red China. (Remember Harry Truman’s “police action.”)
(5) The Peoples Liberation Army of the PRC has formally doctrinalized the concept of “assymetrical warfare” – which happens to be international terrorism’s very playbook. Two of its most senior generals published a major work on this doctrine about two years ago.
(6) PRC treated America with open contempt after the force-down of our spy plane on Hunan almost two years ago. The message seemed to be: We are unafraid of you, and can abuse you with impunity.
(7) It has been alleged that the Clinton Administration transferred top-secret missile guidance technology to PRC, and God only knows what else. Under the Clinton Administration, a consortium of companies, mainly PRC-domiciled (and thus companies that are, in effect, fronts for the PLA), purchased what was reported to be the last rare-earth magnet manufacturer in the U.S. These devices as essential to certain of our advanced military programs, such as JDAMs. If the Bush Administration doesn’t act soon, the entire factory will be relocated to China (if it isn’t already there yet), and America will no longer have a domestic supplier for these critical military parts.
(8) PRC is not “our friend,” it is not “our ally.” And “competitor” may not be strong enough to denote their posture toward the U.S. As the remaining “superpower,” we are all that stands in the way of the achievement of PRC ambitions in the world. I believe that China intends to be the global hegemon. It has already declared that the twenty-first century is "the Chinese century."
(9) I recently read that Jiang Zemin has stepped down as chairman of the Chinese Communist Party. He remains president, the official head of state. But the real power in China is the CCP, and only the CCP. What does this rather unusual circumstance portend?
(10) As noted, the cyberattack on BoA. Per chance was this an “asymmetrical warfare” attack against a U.S. economic target? Perhaps a “test” of a new kind of “weapon?”
You wrote: “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).…” Well, maybe somebody’s got the code; I.e., PLA intelligence, which I imagine is awfully good, and which perhaps has been aided in recent times by “Friends of Bill.” Would the frequency issue be a problem, if you could insert your bug into the ground operational system, and let it upload the bug to the shuttle for you?
I’m no expert for sure when it comes to these issues. I do wonder – how complicated does a worm have to be to execute its mission? My understanding is that it’s not necessary to actually code an instruction designed to execute a particular task – say, “blow hatch door,” etc. You just need something nasty that can get into the code and run amok. Sooner or later, something bad will happen. You don’t even have to specify exactly what that is in advance.
Well, how’s that for a nutsy scenario! Somebody please – give me a “reality check!!!”
Thanks so much, Zavien Doombringer, for hearing me out (letting me rant).
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