The Big Leap by Charles E. Fritch

It did not terrify Cantrell to know he was up so high and going so fast, going higher and faster than any human before him. He would be up even higher the next day, he remembered, going so high and so fast he would not come down again.

It would be a shame to leave Earth, he knew. There was security in her firmness, with no great space underfoot through which to drop down, down, down. Up here there was emptiness all around. Emptiness and, except for the dull throb of the rocket engines, silence. Out there—he looked up—there would be a greater emptiness, a greater silence, an infinity of nothingness in all directions.