The attempt to send and land astronauts on Mars risks billions of dollars and the lives of those brave enough to attempt it. Is the possible benefit really worth the risk? And is it really achievable? Guiding us through this ethical and scientific minefield is Dr Kevin Fong. Kevin's diverse background in astrophysics, aeronautics and medicine makes him uniquely placed to understand the technical and human challenges of this perilous journey. With the help of the BBC's rich archive and a cast of supporting experts, Kevin leads us through the journey to Mars stage by stage. For Kevin, not only is this the toughest journey we will ever attempt, it is one that he feels we ultimately must make if we are to survive as a species.
NASA launches its most ambitious hunt for traces of life on Mars, landing a car-sized rover in a rocky, ancient river delta. The rover will stow samples for possible return to Earth and test technology that may pave the way for human travel to Mars.
Scientists and modern explorers are determined to send humans to Mars; as NASA builds its first spacecraft to carry astronauts to Mars and tech visionaries devise extraterrestrial colonies, future on Mars might be a reality.
Life once existed on Mars, but a series of devastating mass extinctions have made present-day life nearly impossible. The latest science shows how Martian life keeps bouncing back as it transforms from a watery world like Earth into a desert planet.
Sagan reflects on the future of humanity and the question of "who speaks for Earth?" when meeting extraterrestrials. He discusses the very different meetings of the Tlingit people and explorer Jean-Francois de La Perouse with the destruction of the Aztecs by Spanish conquistadors, the looming threat of nuclear warfare, and the threats shown by destruction of the Library of Alexandria and the murder of Hypatia. The episode ends with an overview of the beginning of the universe, the evolution of life, and the accomplishments of humanity and makes a plea to mankind to cherish life and continue its journey in the cosmos. The Cosmos Update notes the preliminary reconnaissance of planets with spacecraft, the fall of the Berlin Wall and the end of apartheid in South Africa, and measures towards the reduction of nuclear weapons.