Of course any serious error might be fatal.

I was exposed to two dangers; perhaps to three: but to none which I had not fully estimated before even preparing for my voyage.
If I should fail to come near enough to the goal of my journey, and yet should go on into space, or if, on the other hand, I should stop short, the Astronaut might become an independent planet, pursuing an orbit nearly parallel to that of the Earth; in which case I should perish of starvation.

It was conceivable that I might, in attempting to avert this fate, fall upon the Sun, though this seemed exceedingly improbable, requiring a combination of accidents very unlikely to occur.

On the other hand, I might by possibility attain my point, and yet, failing properly to calculate the rate of descent, be dashed to pieces upon the surface of Mars.

Of this, however, I had very little fear, the tremendous power of the apergy having been so fully proved that I believed that nothing but some disabling accident to myself--such as was hardly to be feared in the absence of gravitation, and with the extreme simplicity of the machinery I employed--could prevent my being able, when I became aware of the danger, to employ in time a sufficient force to avert it.