we seven

is an excellent book by the seven mercury astronauts (isbn 978--4391-8103-4). As usual I'm going to quote from a few pages:

By working with the designers and engineers on a brand-new, complicated airplane you learn to ferret out the bugs and problems before they can be built into the system to worry other pilots who will use later production aircraft. [John Glenn]

Looking back on it now, it sounds a bit silly. But it takes little moments like that to build up a person's tolerance of fear and his ability to face the unknown. [Malcomn Scott Carpenter]

When I got back to the States, I served a hitch teaching some younger pilots how to fly. This kind of duty is probably even more dangerous than combat. At least you know what a MIG is going to do. [Virgil Grissom]

A test-pilot is fiercely proud of his profession. [Walter Schirra]

I could not take care of the polyp right away because part of the procedure before they could operate on it was to keep me absolutely quiet for four days and not let me speak… Later on the medics did put me on a week's silent treatment. I had to break it only once when a NASA official called me up from Langley to ask me how my polyp was coming along. I told him he had just interrupted the cure. [Walter Schirra]

In combat, for example, you are thinking about what goes on outside of your airplane… But in test flying you have an entirely different problem. You are concerned about what is going on inside the airplane, and what the aircraft itself is doing. [Deke Slayton]

If you are an amateur in this business, and you just think you are in trouble, you can really get yourself into trouble very fast by doing the wrong thing first. You might be a whole lot better off if you did nothing at all. [Deke Slayton]

In flying, navigation is generally defined as "continuously detecting and correcting infinitesimal errors in the flight path." [Deke Slayton]

The schedule was flexible. We knew that variable factors such as weather, over which we would have no control, could cause delays. [John Glenn]

This panel groups all of the warning lights in one convenient place so we can see at a glance if any problems have cropped up. [John Glenn]

Each part that goes into the capsule has had a prototype tested to destruction to make sure it can stand the rough ride and the temperature changes. The test procedures are extremely painstaking. First, one part is tested; then two parts are linked together and both of them are tested as a unit. The small units are joined into bigger units for further testing, and this process continues until finally the entire machine is ready for a master test. [Malcomn Scott Carpenter]

We adopted three basic principles. First, we would use any training device or method that had even a remote chance of being useful. Second, we would make the training as difficult as possible so that we would be overtrained, if anything, rather then undertrained. And third, except for some wise scheduling of time, we decided to conduct our training on an informal basis. Everyone assumed from the start that we were mature, well-motivated individuals. Everyone knew we were all eager to make good. [Deke Slayton]

The manual went out of date as fast as the capsule grew… In the meantime… we had to work with some early drawings of the spacecraft that had been included in the original specifications. This was a bit like learning how to cook from looking into some chef's garbage pail. [Deke Slayton]

We did not blame any of our problems on such things as gremlins. For one thing, these creatures belonged to another era. [John Glenn]

We also had daily scheduling meetings to keep everyone informed of our progress and up to date on any problems which cropped up. Here is where we reviewed the work being done on the various systems. [Virgil Grissom]

Even though the electronic machines were clever, we did not let them run the show. [Alan Shepard]