Alpha Centauri is a three-star solar system 4.37 light years from Earth, the nearest neighbors of our Sun. A planet has recently been detected in the system, which raises the questions of when and how we will make our first efforts to reach this planet, or some other (relatively) nearby planet, to expand the horizons of the human race. Interstellar Flight takes us through current theories of just how we are hypothesizing doing so.
To date, 3841 planets in the near regions of our galaxy have been identified as potential settlement options, about 1100 of which are confirmed. Most are Jupiter and Neptune-sized planets that orbit close to their corresponding stars. Estimates on the number of Earth-sized planets that could possibly support life in our galaxy fall around nine billion.
The film then turns to the actual distance between us and Alpha Centauri, which is daunting. Historically, our rocketry and space travel technology has centered on chemical propellants, a hindrance that will have to be cast aside and replaced if we are to have any hope of traveling the immense distances to other star systems.
An example of this wildly inefficient propulsion method is given in the form of the amount of fuel required by NASA's space shuttles to reach the 25,000 kilometers per hour necessary to escape Earth's gravitational pull - which measures out to fifteen times the weight of the shuttle otherwise. Needless to say, no craft could possibly carry enough fuel to reach another star if it was propelled by fuel so inefficient.
A number of proposed spacecraft designs with alternative propulsion methods that have came and went since the 1970's are cycled through before landing on what is currently the most desired fuel type - antimatter. The engines hypothesized here would supposedly need only 1/10000 of a gram of antimatter to take a spacecraft with all the necessary cargo to Alpha Centauri.
The hurdles with this form of propulsion lie in the scarcity of, and difficulty in obtaining, it. Other than in incredibly trace amounts, it is not known to be found anywhere outside of black holes - which sets the stage for the possibility that if we ever want to get where we really would like to go, we'll need to go to one of the most feared places in all of physics first.