One of the most startling experiences that I have ever had was one day when we were navigating space about half way between the earth and Mars. I had stepped outside the car with Lord Kelvin, both of us, of course, wearing our air-tight suits. We were perfectly well aware what would be the consequence of detaching ourselves from the car as we moved along. We should still retain the forward motion of the car, and of course accompany it in its flight. There would be no falling one way or the other. The car would have a tendency to draw us back again by its attraction, but this tendency would be very slight, and practically inappreciable at a distance.

Stepping Into Space.

"I am going to step off," I suddenly said to Lord Kelvin. "Of course I shall keep right along with the car, and step aboard again when I am ready."

"Quite right on general principles, young man," replied the great savant, "but beware in what manner you step off. Remember, if you give your body an impulse sufficient to carry it away from the car to any considerable distance, you will be unable to get back again, unless we can catch you with a boathook or a fishline. Out there in empty space you will have nothing to kick against, and you will be unable to propel yourself in the direction of the car, and its attraction is so feeble that we should probably arrive at Mars before it had drawn you back again."

All this was, of course, perfectly self-evident, yet I believe that but for the warning word of Lord Kelvin, I should have been rash enough to step out into empty space with sufficient force to have separated myself hopelessly from the electrical ship.

As it was, I took good care to retain a hold upon a projecting portion of the car. Occasionally cautiously releasing my grip, I experienced for a few minutes the delicious, indescribable pleasure of being a little planet swinging through space, with nothing to hold me up and nothing to interfere with my motion.

Mr. Edison, happening to come upon the deck of the ship at this time, and seeing what we were about, at once said:

"I must provide against this danger. If I do not, there is a chance that we shall arrive at Mars with the ships half empty and the crews floating helplessly around us."

(Spacewalk from 'Edison's Conquest of Mars')