CM Computer display

[voyager3]

IHi everyone, I've a question about the DSKY display in the Apollo CM. Watching Apollo 13 and From the Earth to the Moon, I've noticed that in the top right hand corner of the screen were the words "NOUN" and "VERB" with a number beneath. What did these mean?

[JayUtah]

The commands given to the computer were conceptualized as VERBS (commands) and NOUNS (things to be worked on) to help simplify the interactions. These were assigned two-digit numbers, and the astronauts memorized the important ones. This lets you do everything using a numerical keyboard. Everything the computer could do (e.g., fire the motor, display memory contents) was assigned a verb. You ordered the computer to do something by pressing the VERB key, then the number of the operation you wanted to perform. If the verb you entered needed a noun (i.e., something to work on) then you pressed NOUN and the noun number. Then you pressed ENTER and the computer processed your request.

Verb 35, for example, is the command to light up all the indicators on the DSKY to check for burned out lights. So you press VERB 3 5 ENTER.

The displays on the DSKY tell you which verb and noun were last entered. That can tell you what the other displays mean, especially the three lines of numerical data.

Verb 16 means "display the data item specified by the noun, in decimal, and update the display at one-second intervals." Noun 65 is the internal system clock. So if you say VERB 1 6 NOUN 6 5 ENTER, the numerical display will show you the mission clock and update it every second. Other nouns might refer, for example, to the gimbal angles from the guidance system or the upload/download speed. But if the display says 16 and 65 for verb and noun, then you know that the rest of the display is showing you the clock.

There's another sequence to run a program, but I can't remember what it was. The noun is the program number to run, which will then appear on the DSKY as well. The program might take over the display, ask the operator questions, and so forth.

[voyager3]

Thank you Jay!

[papageno]

jayutah said:

The commands given to the computer were conceptualized as VERBS (commands) and NOUNS (things to be worked on) to help simplify the interactions.

This reminds me of the Zork text-adventure... ;D

[linuxboatr]

The CM computer didn't have enough power to run Zork! Zork is advanced stuff compared to the CM user interface. But the CM computer had to fit in a small space and be straightforward to use. It isn't pretty or glitzy but I can appreciate the simple elegance of the design.

Matt

[JayUtah]

The AGC "user interface" included many of the switches and controls on the panel. A general-purpose computer has to have a general-purpose interface. An embedded system can use special-purpose controls.

For example, the digital autopilot program was usually running. It has no DSKY outputs. Its "outputs" are the RCS jets. It has no DSKY inputs. Its inputs include the state vector maintained in memory and the deadband selector switch on the pilot's console. That controls how far off the CSM can be from its desired heading before the computer decides to correct it.

The AGC had no representation for text. To many that's a curious and crippling omission. To the engineer its the judicious deletion of a feature that was not necessary and would have needlessly complicated the design.

[Count Zero]

That reminds me of the movie Red Planet, where Val Kilmer finds an unmanned Russian probe on Mars, and unscrews a side panel to access a computer monitor and keyboard. I can just see the Hollywood writer justifying that: "Well, like, y'know, duuuhhh! It's a computerrrr! Of course it'll have a keyboard & monitorrr! Y'know my friend Barry? He's got this computer that is like, sooo radical... Hey, y'wanna go to Starbucks?"

Somewhat more subtly, would a probe need an access pannel that could be removed and replaced?

I seem to recall an Apollo mission where they needed a screwdriver, but didn't have one. I forget the details. I'm drifting...

[Data Cable]

Forget the keyboard... what about that stupid bear graphic? Are the writers implying that Russian engineers design their equipment to be operated by three-year-olds? Or is it a fraction of a molecule deeper than that, implying that the Russian government/space program is so strapped for cash that it needs to scavenge children's educational/entertainment products to run their probes, with only a minimum of code alteration?

(Öy, don't get me started on the problems with that flick...)

[dwight]

What about that stupid robot that makes scary sounds while hunting its former masters? I often think if you took the good parts from Red Planet and mixed them with the good parts of Mission to Mars, you'd have a top notch film.

[Data Cable]

dwight said:

I often think if you took the good parts from Red Planet and mixed them with the good parts of Mission to Mars, you'd have a top notch film.

But then, one could say the same about, for example, Showgirls and Dude, Where's My Car?

[PhantomWolf]

Well one can say it, but that doesn't make it right.

[thestargazer]

linuxboatr said:

The CM computer didn't have enough power to run Zork! Zork is advanced stuff compared to the CM user interface. But the CM computer had to fit in a small space and be straightforward to use. It isn't pretty or glitzy but I can appreciate the simple elegance of the design.

Matt

Now hey, I take umbrage at that: Zork 1 would comfortably run on a 16k Apple computer and - issues of processing speed and storage aside, I believe the ... was it 14k-words?... of command storage the CM computer had would handle that quite nicely.

Of course the question of getting the thing playable, that's another matter.

Eagle 1: "Houston, we are go for next room, over."
Houston: "Roger that, Eagle 1. Be advised it is pitch black and you are likely to be eaten by a grue. Advise you go for torch burn on mark."
Eagle 1: "Ah, roger that Houston. Go for torch burn in five-four-three-two-one-mark and LIGHT LAMP, over."
Houston: "Copy your LIGHT LAMP, Eagle you are in a small room, there is a table here with a paper sack and a sword inside a jeweled scabbard. What next, over."
Eagle 1: "Copy room description, houston, say SCORE."
Houston: "Eagle one we make score at ten out of a possible one thousand ranking you as Novice Adventurer. Advise you collect items to put in living room display case to raise score, over."

[gr814u69]

Somewhat more subtly, would a probe need an access pannel that could be removed and replaced?

Wasn't that on Apollo 14 when they had the problem with the "ABORT" button? Something about they had to take a panel off. They found a loose ball of solder.

[ktesibios]

I found two descriptions of the ABORT switch problem. This:

An abort command was set in the lunar module guidance computer and the indication was observed by Flight Control during lunar module activation, about 4 hours prior to scheduled powered descent initiation. A procedure was uplinked to the crew which reset the abort command and led to the- conclusion that the abort switch had malfunctioned. Subsequently, the abort command reappeared three times and, each time, the command was reset by tapping on the panel near the abort switch. A procedure to inhibit the primary guidance system from going into an abort program was developed in the interval prior to powered descent, and was uplinked to the crew for manual entry into the computer. The first part of the fourpart procedure was entered just prior to powered descent initiation and the other parts after throttle-up of the descent engine. Had an abort been required, it would have been accomplished using the abort guidance system and would have allowed reestablishment of the primary guidance system by keyboard entry after the abort.

from www.hq.nasa.gov/office/pao/History/alsj/a14/a14mr11.htm

and this:

On the way down, the LM "Antares" had two problems. First, the LM computer began getting an ABORT signal from the ABORT switch. NASA believed that the computer might be getting erroneous readings like this if a tiny ball of soldering material had shaken loose and was floating between the switch and the contact, closing the circuit. The immediate solution - tapping on the panel next to the switch - did work, but if the problem recurred after the descent engine fired, the computer would think the signal was real and would initiate the sequence to blow the Ascent Stage back into orbit. NASA and the software teams at MIT scrambled to find a more permanent solution - reprogramming the computer to ignore the signal - and Shepard and Mitchell were able to accomplish this just in time.

from en.wikipedia.org/wiki/Apollo_14

Nothing about the crew taking anything apart. Since the LM wasn't returned to Earth, obviously no post-mission inspection of the switch was possible. NASA deduced that the most likely cause of the problem was a conductive particle from the way the problem behaved.