I recently ran across a few quotes that I feel worth mentioning here. The first 3 relate to technology, and are noteworthy. The remaining ones deal with stupidity. They may seen overly negative to some, but they are intended to be read with an bit of humor.
Arthur C. Clark’s three “laws” of prediction:
- When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
- The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
- Any sufficiently advanced technology is indistinguishable from magic.
The 3rd law was rephrased by NASA’s J. Porter Clark into one of my favorite quotes:
“Sufficiently advanced incompetence is indistinguishable from malice.”
A corollary to this is called Hanlon’s razor:
“Never attribute to malice that which can be adequately explained by stupidity.”
And while I’m on the subject, here’s a great quote from Albert Einstein:
“Only two things are infinite, the universe and human stupidity, and I’m not sure about the universe.”
Finally, German General Kurt von Hammerstein-Equord (what a name) shared these observations about the risks of human stupidity:
“I divide my officers into four classes; the clever, the lazy, the industrious, and the stupid. Each officer possesses at least two of these qualities. Those who are clever and industrious are fitted for the highest staff appointments. Use can be made of those who are stupid and lazy. The man who is clever and lazy however is for the very highest command; he has the temperament and nerves to deal with all situations. But whoever is stupid and industrious is a menace and must be removed immediately!”
O’Reilly has a great interview up with NASA’s Peter Gluck, project software engineer for the Mars Phoenix Lander. I always find the design and implementation of mission-critical systems interesting. In short, they’re running a radiation-hardened system (the RAD 6000 board) with a 33MHz CPU, 128 megabytes of RAM, and a PCI peripheral interface… pretty advanced stuff for space. This usually surprises people when they first hear about these systems, but the circumstances require proven technology that is hardened against the perils of outer space (for example, the Hubble Space Telescope was recently upgraded to an Intel 486 processor… the Space Shuttle still runs on hardened PDP-11s).
The software is written in C and running on the VxWorks real-time OS… Lockheed Martin (who wrote the control systems) switched from ADA to C a few years back. There are plenty more interesting details in the article. Here are a few teasers:
The RAD 6000 has built in error detection and corrections. So the hardware does RAM scrubbing. There is a RAM scrubbing that occurs on a continuous basis. And beyond that, we have internal fault protection that monitors the health and safety of the software. And if a software task, for example, fails to respond to a ping, we have pings in the system, then the fault protection task will declare that a fault has occurred and will safe the spacecraft. And what that means, by “safeing”, we mean that the spacecraft will enter into a power and communications safe mode where it will just sit and wait for the ground to respond. It’ll basically phone home and say, I’ve got a problem; somebody tell me what to do.
So if it were to completely lock-up, the hardware has to be stroked every 64 seconds. There’s a watch-stop timer. And so if that 64 second period expires, then the hardware resets and the software is rebooted, and hopefully that clears whatever error occurred. Now in the event that that doesn’t work, we have a whole second set of avionics onboard. So the hardware will try to boot to the same side, and if the same side doesn’t come up and start stroking the watch-stop timer, then it will swap to the other side and boot the first side.
Interviewer: Am I right in assuming that there’s very little process separation in the older RAD 6000 boards?
Peter: Exactly… We have strict coding guidelines that we use. We don’t allow dynamic memory allocation, for example.
These are true fail-safe systems… not the stuff we mortal engineers play with. Click HERE to read the rest of the interview.
So, there was a lot of hoopla today over the discovery that Mars’ soil may be similar to that found on Earth and thus conducive to supporting life. The Phoenix Mars Lander previously found water in the soil, which was exciting enough. Now, it has shown that the soil has a pH between 8 and 9, and contains magnesium, sodium, and potassium. This has got a lot of people excited about the possibility of finding life (alive or exstinct) on Mars. They are also excited about the possibility of growing food for extended missions there.
You can read about it HERE on the New York Times website.
I’m wondering how long until NASA applies for farm subsides?
I saw this video about 6 months back and I was really impressed. The most interesting part to me is after the rocket clears the base… very surreal. As a side note, the Discovery channel is beginning a special this Sunday about the US space program called “When We Left The Earth”. I expect this video to be a part of it.
A few facts about this video:
- The stuff falling from the rocket is ice. The Saturn engines burned liquid hydrogen and oxygen, which is VERY cold.
- The engines generate a strong vacuum, which is why the ice and smoke are initially sucked down into the opening in the launch pad base.
- The short section of dark exhaust coming out of the nozzles (right before the exhaust fire gets bright) is due to the cool liquid hydrogen that is used to cool the nozzles.