• 
  Kevin R. Grazier

  El însuși
• 
  Mike Capps

  Himself - Technology Theorist
• 
  William J. Birnes

  El însuși
• 
  David Brin

  Himself - Astronomer, Author
• 
  Erik Dellums

  Himself - Narrator (voice)
• 
  Charles Duke

  El însuși
• 
  Stanton Friedman

  El însuși
• 
  Seth Shostak

  El însuși

• 
  Peter H. Schultz

  El însuși
• 
  Chris McKay

  Himself - Phd., NASA Astrobiologist
• 
  Jerry Ehman

  Himself - Phd., Astronomer
• 
  Robert Gibson

  Himself - Astronaut (as 'Hoot' Gibson)
• 
  Marc D'Antonio

  Himself - Astronomer & Image Analyst
• 
  Kevin H. Baines

  Himself - Phd., NASA Planetary Scientist (as Kevin Baines)
• 
  Joseph Dwyer

  Himself - Professor, Atmospheric Scientist

• 
  Ningyu Liu

  Himself - Professor, Atmospheric Scientist
• 
  Dick Carrigan

  Himself - Phd., Physicist