The Martian (2015)
RTGs are essentially batteries powered by radioactive plutonium-238. As the plutonium naturally decays, it generates heat, and the battery casing turns the escaping warmth into electricity.
Plutonium-238 is pretty much impossible to turn into a nuclear weapon, according to the Environmental Protection Agency. Its radiation is not the kind of dangerous, skin-piercing radiation that humans have to worry about (unless it is inhaled).
Still, a nuclear battery is dangerous to have around because it's very hot.
- Mars has a reddish-orange glow during the day from all the dust.
- Sunrises and sunsets appear blue because Mars has almost no atmosphere.
- One day or "sol" on Mars is about 37 minutes longer than an Earth day. The natural human circadian rhythm (or sleep-wake cycle) is about 24 hours and 11 minutes, but experiments have shown that humans have no problems adapting to cycles varying from 23 hours 30 minutes to 24 hours 36 minutes; so humans would not experience major disruptions of their biological clock on Mars.
- One Martian year is nearly two Earth years. That's because Mars orbits the Sun much farther away than Earth, so it takes a lot longer for the red planet to complete one lap.
- The average surface temperature on Mars is a chilly minus-80 degrees Fahrenheit (minus 62 degrees Celsius). But temperatures can swing from a low of about minus-195 degrees Fahrenheit (minus-126 degrees Celsius) in winter, to a comfortable 68 degrees Fahrenheit (20 degrees Celsius) during the summer.
- Gravity on Mars is only about 40% that of Earth's, so a person would be 60% lighter (but not Moon-bouncing light).
- Mars has barely any atmosphere - about 1% of the density of the cozy atmospheric blanket around Earth. That's not enough to protect the surface from dangerous space radiation.
- Dust storms can envelop the planet for days at a time. In the novel, these storms cause important plot points other than the initial stranding of Watney.
NASA already has working prototypes of Mars habs, complete with oxygenators, water reclaimers, and airlocks to protect astronauts from the nearly airless, radiation-bombarded surface of Mars.
The space agency also recently hosted a competition to see who could design the best 3D-printable Mars Hab. Some of the designs might actually end up on the red planet some day.
In terms of the entire Ares III mission, starting from Earth departure and including the emergency Martian evacuation and the Earth/Martian gravity assists to rescue Mark, the total length was 772 sols. This means the entire Ares III mission as a whole lasted 795 earth days (or roughly 2 years and 2 months).