Scientists are considering the possibility of sending humans to Mars in the coming decades. Although there have been successful manned missions to the Moon in the 1960s and 1970s, Mars is 150 times further away from Earth

The reading passage explores three possible problems of project sending human to Mars. However, the lecturer respectively proposes three solutions appropriate to the reading problem. At first, the reading mentions that the trip to the Mars take more time than travel to the Moon and astronauts may remain out of food because the capacity of cargo is too limited to carry two-year supply. While the professor suggests hydroponic technique as a practical way to provide food, water and oxygen. By adapting hydroponic technique, astronauts cultivate plant in the spacecraft and use the fresh air released by theses plants. Additionally, they are able to recycle water in order to drink it. Secondly, although the author of the passages points out the negative impact of exposing to zero-gravity upon the astronauts muscles and bones, the professor proposes number of exercise astronauts learned from their previous experience like regular practice which is useful for the muscles or vitamin, calcium diet for bones. Finally, the reading passage states that hazardous space radiation from sun needs constructing protective shells for human, but it is impossible because this kind of protective shells would increase the weight of spacecraft. Whereas, the lecturer explains that emitting solar radiation occasionally occur and scientists can monitor radiation and alarm the astronauts to go under small shell when they detect that sun will begin to radiate.