deep space

• deep-space
• deepspace

Coined by American science fiction author E. E. Smith in 1934 in his novel Triplanetary, first serialized 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, E. E. "Doc" Smith, “Triplanetary”, in Amazing Stories, volume 6, number 5, page 54:

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

   • 2005, Lawrence W. Townsend, “Implications of the space radiation environment for human exploration in deep space”, in Radiation Protection Dosimetry, volume 115, →DOI, pages 44–50:

     Human exploration of the solar system beyond Earth's orbit will entail many risks for the crew on these deep space missions.

deep space (uncountable)

1. All of space beyond the gravitational influence of Earth, or outside the Solar System, or distant from stars
   • 1937 December, E. E. "Doc" Smith, “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

• Jeff Prucher, editor (2007), “deep space”, in Brave New Words: The Oxford Dictionary of Science Fiction, Oxford, Oxfordshire, New York, N.Y.: Oxford University Press, →ISBN, page 34.
• Jesse Sheidlower, editor (2001–2024), “deep space n.”, in Historical Dictionary of Science Fiction.