The reading passage mentions three problems that may happen during human trips to Mars. However, the professor in the listening material believes all these problems can be solved.
The first problem is that because the space on the crafts is too limited, astronauts are not able to bring enough life essentials such as water, food and oxygen. But according to the lecturer, astronauts can use a technique called hydroponics. This enables people to plant crops with their roots in water rather than in soil, which requires relatively little space. Also, the growing of plants releases air and recycles water, which tackles the shortage of water and oxygen.
Second, the reading selection worries that astronauts will work in zero-gravity environments. This does harm to their bodies by decreasing their bone density and muscle mass. Nevertheless, the listening argues that this is not a problem. During space trips in recent years, people have developed strategies by which they can manage the effect of zero-gravity. For example, by regular exercises and taking in vitamins and minerals, the decrease of bone density and muscle mass can be slowed down.
Finally, while the passage is concerned by the dangerous radiation that astronauts will be exposed to, the speaker in the listening is rather optimistic. She says that the level of the radiation would not be dangerous all the time. It threatens people only when the Sun is particularly active. Then the spacecrafts can be equipped with both equipment that monitors the level of the radiation and a shelter that shields astronauts from the radiation. When the monitor detects dangerous radiation, people can hide in the shielded area, so the problem mentioned in the reading is not as troublesome as expected.