deep space

• deepspace

Coined by American science fiction author E. E. "Doc" Smith in his 1934 novel Triplanetary, first serialised in Amazing Stories. After deep sea.

deep space (not comparable)

1. Of or in the area of space beyond the gravitational influence of Earth, or outside the Solar System
   • 1934 April, Smith, E. E. "Doc", “Triplanetary”, in Amazing Stories, volume 6, number 5, page 54:

     Bradley swore a mighty deep-space oath and braced himself against certain annihilation.

deep space (uncountable)

1. All of space beyond the gravitational influence of Earth, or outside the Solar System
   • 1937 December, Smith, E. E. "Doc", “Galactic Patrol”, in Astounding Science-Fiction, volume 20, number 4, page 73:

     Part of the time he spent in the speedster dashing hither and yon. Most of it, however, he spent in the vastly more comfortable mauler; to the armored side of which his tiny vessel clung with magnetic clamps while he slept and ate, gossiped and read, exercised and played with the mauler's officers and crew, in deep-space comradery.

• outer space, space

• “deep space” in Brave New Words: The Oxford Dictionary of Science Fiction, Oxford University Press, 2007, →ISBN, page 34.
• deep space n. at the OED Science Fiction Citations Project