Space hitch-hiker.
D018480:Astronauts; D055818:Public-Private Sector Partnerships / Q000191:economics / Q000639:trends*; D012106:Research / Q000191:economics / Q000639:trends*; D012107:Research Design; D012108:Research Personnel; D013026:Space Flight / Q000191:economics / Q000706:statistics & numerical data / Q000639:trends*; D018531:Spacecraft / Q000191:economics; D014195:Travel / Q000191:economics / Q000706:statistics & numerical data / Q000639:trends*; D014481:United States; D018557:United States National Aeronautics and Space Administration; D014893:Weightlessness