Okay, so I wrapped up Digital Apollo recently (MIT Press, David Mindell) and I thought it was overall pretty good. The part I enjoyed the most was at the end when he talks you through the landing process and then talks about the landing experienced by each crew. They were all a little different.
You also get a good explanation of the genesis of the Apollo Hardware. Provided I remember some earlier late night reading sessions, the hardware has heritage in a computer intended for a Mars mission. The packing techniques were from guided missiles (makes sense). I'd heard that before. And the software (which was considered something of an afterthought at first) did a lot of simulating analog solutions to problems. This section of the book is something I want to go back over in greater detail sometime. Most other versions of this story concentrate on the word width, memory size, clock speeds, so on and so forth, but not what needed to be done.
Also inside, some good discussion on the X-15 and how much intervention the astronauts wanted. Should the astronauts literally fly the ship or just supervise systems ? Some folks thought you'd use stick and rudder and fly the rocket off the pad, literally. Another camp was for fully automatic (Ranger, Surveyor) operation. What happened was a mix of the two, a sort of semi-automatic mode. Really, I think the Apollo flight software would have been smaller / simpler if the pilot didn't have so much control over the trajectory. Why? Because a lot of points had to be coded into the software where you gave the operator (oops, astronaut) the chance to change control, or edit a setting, so on and so forth. Maybe two separate programs (each on a computer) with a big toggle switch (auto, manual) would have been worth looking at ?
Anyway, it's a fun book if you're into technical history.
No comments:
Post a Comment