kollektief

An intrepid photographer named Thierry Legault has captured the shuttle Endeavor and the space station crossing the sun:

also check this out, a certain NYC band gets a fleeting public reference:

the rest of the AGC discussion may be slightly delayed, I’m struggling with a lack of time in the evening and the need to better understand the Executive function in order to describe it succinctly. there will hopefully be some fun machine code discussion.

dan

_ _ _ _ _ _ _

Here’re a few interesting tidbits you won’t easily find elsewhere – the following are cribbed from a transcription of a 1982 lecture by David Scott (’62, SM, EAA, Aero Astro) about the user’s view of the AGC.

***** Space rendezvous – unbelief and the learning curve:
“In Apollo 9, we did the first Apollo rendezvous. Rusty and Jim got in the lunar module and separated from myself in the command module. They went out about 60 miles and then came back in a rendezvous. Today, after all the Apollo work and everything, nobody thinks that is a big deal because we’ve done it so much…

As a matter of fact, I then got to fly Apollo 15, and we had done the rendezvous so many times that by my last flight, you could actually use a watch, and a rate of angle change, and a piece of paper, and do a rendezvous. It becomes very straight forward as long as you don’t have too many uncertainties or a failure of some sort. It took me back to the early sixties when people wondered if we could even do one, and twelve years later we could do it on the back on an envelope.
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The two equipment alarms that Armstrong and Aldrin had while trying to land the Lunar Module were Alarm 1201 and 1202. These alarms resulted in about a half minute in which neither of them knew whether they needed to abort the landing while they were 6 miles up, falling towards the ground, burning fuel, rebooting their computer, and waiting for Mission Control to give feedback.

It turns out the landing had a lot of interesting issues going on all revolving around the Apollo Guidance Computer.
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1. experimenting with stencils and screens

I’ve been working on some printing lately. I started out with spraypaint stencils, but then wanted to try for more detail, so i bought myself a nice nortech 18×20 inch screen and a photo emulsion kit. I really like the nortech, but i’m worried that it may be difficult to properly stretch my own fabric onto later. They have a strong solid frame, but they glue the screen on instead of having one of those things like the speedball with the mitred groove.

here’s my first experiment (salvaged from a bigger print that wasn’t very perfect):

2. quantum tic tac toe

http://en.wikipedia.org/wiki/Quantum_tic_tac_toe

This is a pretty cool game which is a lot like normal tic tac toe, except that whenever it’s your turn you choose two spots instead of one, which you then label X1 and X1, for example. You have not yet actually occupied those squares, but you have quantumly entangled them. Each square can be entangled with as many other squares as the players want.

When three squares become entangled in a loop (one square connects to the next, which in turn connects with the next, which then connects back to the first square) the squares in question all collapse to classical tic tac toe spaces and are evaluated as normal. It sounds like fun!

3. Apollo 11 code

NASA has released the original Apollo 11 Command Module and Lunar Module code as open source. This code, which was developed at (what was then MIT’s) Draper Labs, can be run on the Apollo Guidance Computer emulator yaAGC.

source files for the Command Module: Comanche055
source files for the Lunar Module: Luminary099

The Master Ignition Routine has some cool comments, i especially liked the use of latin religious phrases:

#	Assemble revision 001 of AGC program LMY99 by NASA 2021112-61
#	16:27 JULY 14, 1969
...
# Page 731
# BURN, BABY, BURN -- MASTER IGNITION ROUTINE
...
# THE MASTER IGNITION ROUTINE WAS CONCEIVED AND EXECUTED, AND (NOTA BENE) IS MAINTAINED BY ADLER AND EYLES.
#
# 		   HONI SOIT QUI MAL Y PENSE
#
#	***********************************************
#		TABLES FOR THE IGNITION ROUTINE
#	***********************************************
#
#                       NOLI SE TANGERE

P12TABLE	VN	0674		# (0)
		TCF	ULLGNOT		# (1)
		TCF	COMFAIL3	# (2)

et cetera et cetera
and at the end:

...
  		TCF	GOTOP00H	# V34E TERMINATE
  		TCF	P40A/P		# RECYCLE
GOBACK		CA	TEMPR60
  		TC	BANKJUMP	# GOODBYE.  COME AGAIN SOON.

4. astronaut spoor

and just in case any of you missed it, the lunar orbiter caught this picture of the Apollo 14 leftovers: