Despite what others have said about this film "trying too hard to prove interstellar travel is impossible", I thought they covered the "pro-space travel" researchers extensively and the people interviewed who cast doubt on the plausibility of some of these plans were all relevant experts (NASA engineer who worked on Mars rover, astronaut from the intl space station, head research at CERN, etc.).
It wasn't so much about proving space travel is impossible but getting a fullsome look at the spectrum of researchers who look for solutions to the problems of space travel and those that work in related areas. People who are developing solutions for life on Mars or interstellar travel require funding, and that funding is tied to the utopian stories they tell about what they will achieve. The NASA guy or the CERN guy don't get funding by throwing cold water on these claims, their work just happens to give them certain relevant info regarding these potential space travel solutions.
It is fun to imagine all the great possibilities of life as a miner on Mars, but the reality of 12x higher radiation and drinking recycled urine for generations is also a part of that dream.
I would recommend this film to anyone who enjoys hard look documentaries with interesting and relevant interview subjects.
Not surprisingly this film tends to make people who are bought into the contemporary techno-utopian fantasy of being an "multi-planetary species" a bit mad.
