Reviews for Digital Apollo: Human and Machine in Space Flight

1. How man and machine reached a working relationship in Apollo

   Rated 4 out of 5 stars, March 12th, 2010

   When NASA set out to recruit astronauts for the Mercury, Gemini and Apollo programmes they limited their selection to test pilots (mainly military), with the consequence that astronauts were pilots who wanted to "fly" their spacecraft. However piloting in space is governed by Newtonian mechanics rather than aerodynamics, and humans simply don't have the ability to navigate a spacecraft in deep space without considerable assistance from auto-pilots, radars, gyroscopes, accelerometers ... and, inevitably, computers to tie all this information together.
   
   This book considers the technical development of the digital computer used in the Apollo Guidance and Navigation Computer, how the astronauts responded and adapted to this new method of flying, and how they in turn influenced the development of the computer and navigation system to suit their needs. So, unusually, the book covers both the development of the technology and the psychology of the human response to this.
   
   The author traces the development of automated guidance systems in a logical progression from the early ballistic missiles, through the early experimental supersonic flights (X15 etc) to the NASA spacecraft of the 1960s. There is a wealth of detail about how MIT (who got the Apollo guidance contract without any competition, which raised a few hackles) developed the guidance computer from scratch. This in itself is fascinating, for example the "programs" were wound into "ropes" of magnetic cores by ladies with knitting needles! Apollo was also the first example of "fly by wire": the astronauts had hand controllers for the attitude thrusters, but their input had to be modified by the computer so that they got the response they expected.
   
   In parallel with this the author describes the inevitable tensions between the "stick and rudder" test pilots who wanted to fly the craft, and the automated guidance gurus who saw the astronauts as superfluous to piloting in space. It is here that I feel the book falls down a little since the author is clearly biased in favour of the computer and against the human pilot when it comes to space-flight. His approach, especially in the early chapters, is almost patronising in this respect and nearly caused me to give up on the book in irritation. However I am glad that I persevered because the later chapters are both more interesting and also give a more balanced account of how both men and machines adapted and learned to work with each other.
   
   To give an example the astronauts insisted upon having an "8 ball" artificial horizon built into both command and lunar modules to give them a sense of their current orientation. This added weight and complexity, and was considered unnecessary by some, so there was a tussle between management and astronauts leading to its repeated insertion and deletion from the spacecraft. The astronauts won, and it is just as well that they did because a novel use of the "8 ball" was required to orient Apollo 13 during its manually controlled burn on the way back to the earth.
   
   Another example is the final landing on the moon: the lunar model had the ability to land itself, but *every* lunar module commander took over manual control for the last few hundred feet - this was true piloting, and entirely justified in the case of Apollo 11 which would otherwise have landed in a field of boulders. However every simulation in which the astronauts tried to "fly" the lunar module by hand all the way from lunar orbit to surface resulted in a crash - both sides of the argument had to recognise their limitations.
   
   In reality it took both men and machines working together to perform a manned moon landing, neither could have done it reliably on their own, and had the author accepted that and written the book in a more objective and unbiased fashion I would have rated it 5 stars.