interplanetary

from WordNet (r) 3.0 (2006)

interplanetary
    adj 1: between or among planets; "interplanetary travel"

from The Collaborative International Dictionary of English v.0.48

Interplanetary \In`ter*plan"et*a*ry\, a.
   Between planets; as, interplanetary spaces; interplanetary
   travel. --Boyle.
   [1913 Webster +PJC]

from Moby Thesaurus II by Grady Ward, 1.0

48 Moby Thesaurus words for "interplanetary":
      Cynthian, anagalactic, asteroidal, astral, astrologic,
      astrologistic, astrologous, astronomic, astrophysical, celestial,
      circumplanetary, cislunar, empyreal, empyrean, equinoctial,
      extragalactic, galactic, heavenly, heliacal, intercosmic,
      intersidereal, interstellar, lunar, lunary, lunate, lunular,
      lunulate, meteoric, meteoritic, nebular, nebulose, nebulous,
      planetal, planetarian, planetary, planetesimal, semilunar,
      sidereal, solar, sphery, star-spangled, star-studded, starry,
      stellar, stellary, terrestrial, uranic, zodiacal