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cvanc

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Hi troops-

We all remember NASA Facts, right? (At least the older amongst us...) This was a years-long series of short publications NASA issued to the general public. I remember sending away for them when I was a kid and waiting impatiently for a big envelope full of them to arrive.

I have been searching the Net for info on these or an archive where they can be viewed. I find nothing. Have these really disappeared without a trace? Some of them were so cool (wall posters and everything).

Maybe we should try to gather our collections and get them scanned and online somewhere?
 

georgegassaway

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That's one of the annoyances of the wide public use of the internet. Things and news that happened before it became popular often does not exist, or is incredibly hard to find.

I'd suggest you ask this on the "NASA Space Flight Forum" , probably the General section.

https://forum.nasaspaceflight.com/

UPDATE - On later recollection, the publications I speak about below were not NASA Facts. They were NASA Tech Briefs. But I'll leave my post as originally written, other than this paragraph and the name correction.

I have (or had) a few dozen of those from the mid to late 1980's. Do not recall if I got some of them in the mail of if someone gave them to me (maybe both. Someone definitely gave me some and then I may have signed up, not sure).

One issue that I was given involved an incredibly simple design for a sun-tracker sensor, to be used by a controller drive system to aim solar panels directly at the sun. It involved two photoresistors in series, facing upwards. With a vertical "wall" between them, and a "T" sun shield at the top of the wall so that if the sun faced the sensors directly, that half of both photoresistors would be shaded. Now actually it may have bene different , the photoresistors may have been inside of a short tube with a ring on top with a square opeing in it, providing the same sort of shading effect on half of each photoresistor. I might be thinking of the wall and "T" sun shield as something I considered at first for my own project, or possibly that was an illustration to show the basic idea.

At the time (1988), I was working on Sunguidance, but was using photo-transistors and comparators for a very crude set-up to command a servo to move a canard 15 degrees left or 15 degrees right. Very crude control and over-complex circuitry. Taking a cue from that solar tracker in NASA Facts, I tried out photoresistors. I used a different approach than the "T" shade method, had the photoresistors angled outwards some, with some styrene plastic to reduce the overall sunlight (direct sunlight oversaturated them for my needs). By having them wired in series, then a voltage tap between them produced a variable voltage, which was exactly 50% of the input voltage when pointed straight at the sun. So I was able to delete the comparator circuits completely, and just hook up the voltage output to a simple servo-driving circuit that could use voltage input, adjusting so when the model was pointed at the sun, the servo for that axis was adjusted by a trimpot in the servo circuit to point the control surface straight. As the model was pointed away from the sun, the sensor voltages changed which then caused the control surfaces to move to bring the model pointing back towards the sun.

So, that NASA Tech Briefs issue made a huge difference in my sunguidance project, it was far simpler to use photoresistors in series. And it was NAR Board member, and NASA employee at MSFC Huntsville, Vince Huegele, who gave it to me (as well as at least some other issues).

I think I still have them in storage (after a few moves) but I can't access them.
 
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XolveJohn

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If you use IR phototransistors, you could home in on a jet engine. But get rid of the analog stuff, try

a PICAXE chip. I used one on an industrial project, worked great. Easy to program, built in A/D. I hate C, could never learn it, although pretty comfortable with assembly code for PICs.

Oh, and don't violate the safety code!
 
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