Colonization of Mars The colonization of Mars by humans is an ongoing debate. Some people want to colonize the planet Mars. Satellite imagery shows that there is frozen ground water on the planet. Mars also has a thin atmosphere. Because of this, it has potential to host humans and other organic life. That makes Mars the best choice for a thriving colony off the Earth. The Moon has also been proposed as the first location for human colonization but it is not known to have much air or water. It only has 0.16% air and has 14% water. There are many factors humans on Mars will go through, such as the risks in landing on the planet within gravity wells. Many organizations support the colonization of Mars. Earth and Mars The Earth is much like its "sister planet" Venus. - The Martian day (or sol) is similar to Earth days. A solar day on Mars is 24 hours 39 minutes 35 seconds and 244 milliseconds. - Mars has a surface area that is 28.4% of Earth's. It is slightly less than the amount of dry land on Earth (which is 29.2% or Earth's surface). The radius of Mars is half that of Earth and only one-tenth the mass. This means that it has a smaller volume (~15%).

For planning of Mars surface missions, to be operated on a sol-by-sol basis by a team on Earth (where a "sol" is a Martian day), activities are described in terms of "sol types" that are strung together to build a surface mission scenario. Some sol types require ground decisions based on a previous sol's results to feed into the activity planning ("ground in the loop"), while others do not. Due to the differences in duration between Earth days and Mars sols, for a given Mars local solar time, the corresponding Earth time "walks" relative to the corresponding times on the prior sol/day. In particular, even if a communication window has a fixed Mars local solar time, the Earth time for that window will be approximately 40 minutes later each succeeding day. Further complexity is added for non-Mars synchronous communication relay assets, and when there are multiple control centers in different Earth time zones. The solution is the development of "ops efficiency factors" that reflect the efficiency of a given operations configuration (how many and location of control centers, types of communication windows, synchronous or non-synchronous nature of relay assets, sol types, more-or-less sustainable operations schedule choices) against a theoretical "optimal" operations configuration for the mission being studied. These factors are then incorporated into scenario models in order to determine the surface duration (and therefore minimum spacecraft surface lifetime) required to fulfill

Human expeditions to Mars will require adaptation to the 24.65-h Martian solar day-night cycle (sol), which is outside the range of entrainment of the human circadian pacemaker under lighting intensities to which astronauts are typically exposed. Failure to entrain the circadian time-keeping system to the desired rest-activity cycle disturbs sleep and impairs cognitive function. Furthermore, differences between the intrinsic circadian period and Earth's 24-h light-dark cycle underlie human circadian rhythm sleep disorders, such as advanced sleep phase disorder and non-24-hour sleep-wake disord