Slashdot Mirror
Apollo 12 at 35
neutron_p writes "Thirty-five years ago this week, the sedentary, fine-grained powder began to rise, billow and race off toward the horizon. Soon after - at 1:54:35 a.m. EST on Nov. 19, 1969 - the lunar module Intrepid landed, bringing two more humans to the surface of another world. Apollo 12 commander Pete Conrad and lunar module pilot Alan Bean would be on the Moon for more than 31 hours, with crewmate Dick Gordon orbiting above in the command module Yankee Clipper."
Its amazing that those guys had 256k of memory (I think, maybe that was the space shuttle), and they managed to write the flight control programs without any bugs. Programmers today have trouble with 256 megs of memory
"brxref
Just think, this Apollo 12 in all its glory had less computing power than a Furby.
... and in the DRM, bind them.
for those who where not around here's some links to the AGC, DSKY and more:
*Apollo Guidance Computer (AGC)
*slash article with source code listing
*Simulation of Apollo Guidance Computer
*DSKY
peterrenshaw ~ Another Scrappy Startup
Space exploration is cool. I support it. Please allow me to be a devil's advocate:
It seems to me that first world countries are having trouble keeping people procreating. The more advanced the society, the more rights the women, the better things the women have to do than sit at home and rear a half dozen to a dozen kids. Countries like Canada only grow because of immigration. Is it Taiwan that is trying to encourage procreation with subsidies?
NASA is, by every account, a grossly large organization with bureaucracy the likes of which no other entity in the world can hope to measure up to. They're too bureaucratic to save the Challenger. Why not invest incredible amounts of money in some targetted industries (A mach 10 aircraft has little real world application today) and in some "emerging" industries with higher financial risks / humanitarian rewards?
Most of the world ending scenarios seem to have other, potentially more beneficial solutions. Sure, leaving the world to go to the moon or someplace else may be a good way to spread the risk. It would be quite some time to set up the infrastructure to support a self sustaining populace that would not suffer from inbreeding. We may get to the point where this is possible, but NASA is not heading down a path to enable this. If there's a scenario that leads to a (nuclear or CO2) winter, why aren't we making subterrainian cities 10+ feet underground? I would expect one could even justify this by pointing out that such a city would be a prototype for an offworld city. Not that it should necessarily be a self contained monstrosity / joke, but something that starts to set up the infrastructure and maybe includes some geothermal carnot generators (what better way to take advantage of the perpetual winter outside than to make self-sustaining power by harnessing the power of the earth?
The inherant scientific value is irrefutable, but there is little real world application to this.
The dark ages were brought about because innovation stagnated. Everyone ran out of ideas and got so concerned with today that they stopped worrying about tomorrow. These days, we're perhaps on the brink of a newly perceived stagnation. We're masters of the air (airplanes), sea (gigantic boats and submarines) and land (earth destroying cranes, cars, trucks, trains, etc.). Microelectronics are banging against the Laws of Physics, with only nanotechnology seemingly a solution. In our daily lives, few people can think of a way to continue to innovate that makes a difference. Heck, most people don't want to upgrade their life centers (TVs) because the upgrades (HDTV) are too expensive despite how much better they are. Life changing innovation, the kinds of which impact "human happiness" are those leaps and bounds we've been hitting in the past century or two. You can't predict them, an
I keep reading different accounts of that Apollo 11 landing problem.
The account I read was that because the gravitational center of the moon is a bit off-center from the physical shape, there was not enough margin of extra fuel and Neil spotted a bunch of sharp boulders below that he wanted to avoid. So, he took a detour and because of that the craft was almost out of landing fuel and thus fuel warning lights were beeping like crazy.
Neil later said that he kept fairly close to the surface during the detour so that if the fuel did run out, the worse that would happen would be a slightly hard landing. The moon's gravity is low enough that a fall from 50 feet is just jarring rather than fatal.
If Neil was a bit more by-the-book, he would have aborted and launched back into orbit without landing. The control room was turning pale, witnesses said, due to the stress of that landing. If something did go wrong due to that decision, Neil probably would have a boatload of blame on him.
The lopsoded nature of the moon is part of the reason why only one side always faces Earth. I don't know if scientists didn't know it was lopsided back then, or if technicians simply forgot to include that info in their calculations. From what I gather it was a new fact whose magnitude was still under investigation, and thus they had no official numbers for calculations.
For some reason weight constraints on the first few missions were pretty tight and that is why they had so little fuel margin, but later relaxed/expanded the constraints such that moon rovers and other doodads could be included. I don't know why later missions had more payload weight. On the first mission they were so anal about weight that they almost excluded a TV camera. They used the same basic rockets as later missions. Anybody else know the reason for the difference?
Table-ized A.I.
The guy in the control room that made the "go" call to the flight director was named Steve Bales at the GUIDO position. IIRC he was about 26 years old. In his back room was Jack Garman, who was the expert on the computer (most of the "front room" guys have several "back room" support engineers).
Here's a link to the flight loop audio of the decision.
They were prepared to make the call. In the last few weeks before Apollo 11, the "evil" engineers that ran the training simulators really hammered the flight control team on these program alarms. Bales and Garman were very well prepared to respond to those alarms because of this.
The parent is right about being "gutsy". I happen to be a NASA flight controller - and when you are in Mission Control, you are "it". Sometimes, you must make a decision that is time critical, and there is no asking your boss, waiting until Monday, etc. - only you (and your backroom), your knowledge, and your training. While everyone that works there is used to the pressure, many times after a difficult shift you can almost be shaking from realizing what could happen if you made a bad call.
Worst...sig...ever!
The problem that is usually quoted occurred somewhat earlier than that, during the beginning of the descent. Specifically, it was what is known as a "1202 alarm", which was a warning from the real-time part of the computer that it had more tasks to do than it had time for. The reason for this was that the astronauts had forgotten to turn off the rendezvous radar that was going to be used when docking with Columbia, so that the radar interrupts were overloading the task queue. Fortunately, the software was robust enough that the more high-prioritised tasks were still running, so they could land despite this problem.
The landing procedure wasn't quite that critical; sure, the estimate was only 20 seconds of fuel remaining (later revised to 45), but he had after all done 100-odd test landings before. However, he was focused enough on the landing that he didn't turn notice the contact probes touching the ground, and only turned off the landing engine when they were down. The idea was to turn it off as soon as the contact light lit to avoid engine backblast damaging the lander. No harm done though.
The missions were actually of three types. Apollo 11 was a "G" type mission, with a more limited lander, and may be considered the last of the test flights. Apollo 12-14 were "H" missions, which was basically the same as "G", but included the full instrument package which had been removed due to concerns about fuel margines, while 15-17 were "J" type missions which had an improved lander with twice the payload capacity, an LLRV (rover), better moon suits, a bay of science equipment for the command module and so forth.
An intriguing incident with Apollo 12 was that they launched despite fairly threatening clouds in the vicinity, and the rocket was hit twice by lightning during the ascent. Needless to say, this spooked the astronauts a fair bit.
http://www.hq.nasa.gov/alsj/frame.html
Paranoia is simply reality on a finer scale.