near space

Short definition from Wiktionary

Noun

1. 1
   A region of the Earth's (or another planet's) atmosphere or exosphere which is near outer space: The region of the atmosphere between the Armstrong limit (above which atmospheric pressure is sufficiently low that water boils at the normal temperature of the human body) and the Kármán line (one boundary between Earth's atmosphere and outer space); the region of the atmosphere near space.
2. 2
   A region of the Earth's (or another planet's) atmosphere or exosphere which is near outer space: The mesosphere and lower thermosphere.
3. 3
   A region of the Earth's (or another planet's) atmosphere or exosphere which is near outer space: The region of the exosphere between the lower bound of space and the lower bound of orbit; the region of space near the Earth.