Posts tagged 113/365
Meet Scarlet 113/365
Image by SashaW
This is Scarlet, my new netbook. These things are GREAT! They’re mini laptops and (forgive me) they’re oh so cute! This here is the Acer Aspire One. It’s got a 10 inch screen, 160GB and an 8 hour battery!
Image by wbaiv
Michael Collins (Apollo 11 Command Module Pilot) goes into some detail about using the DSKY and the CM’s computer to navigate, including checking where stars actually are versus where the computer and inertial platform expect them to be…
There are books about the guts of this system, which is, in part, to thank for the 0.1" lead spacing of the familiar "DIP" package with 14, 16, 18, 20, etc, pins, .3" wide; Then 24 pin X 0.6"… 40 X 0.6… etc.
Its worth noting that interface, where the tasks were manifold, but could all be imagined. "Noun" and "Verb" prefixes identified the numbers that followed, and were properties of the programs… oh yes, ALL the programs were in the 48K memory. It was like your first Basic class – Landing on the Moon used Program 65 or 66 depending on conditions. The crew memorized all this stuff as well as comitting it to checklists and manuals But when you’ve got 150 hours or 200 hours of activitiy, you can get away with "Noun 15", "Verb 0", "Program 66".
It was at the DSKY that the second to last drama of Apollo 13 happened… they’d coasted out to the moon and back, using the Lunar Module’s inertial navigation platform, and earth based radar/direction finding. But for re-entry into the Earth’s atmosphere, they’d have to say goodbye to the LM (and the mangled Service Module) and set up the Commaond Module’s navigation system so that they could hit the right angle into the atmosphere. Too steep and they’d burn up. Too shallow, and they’d skip out and die when the air ran out (hours, not days).
So as they came up on the Earth, the crew believed they still had enough battery power in the CM to run the reentry but they had to restart the navigation system, align it to the one in the LM, and then they could try to get home. One guy tracking how much power they’re using, one guy driving the spacecraft around and punching the apapropriate buttons here to get the 3 dimensional alignment correct… Whew.. It worked. Not gonna die this time.
And then, of course, they had to actually DO the reentry… which also worked, including parachutes and splash into the ocean.
Machines should work, people should think. :^)