Discovering Mars

For many years, humans have observed Mars and thought about whether we should eventually colonize it. NASA has sent several missions to land on Mars, and they are helping us to determine if we can actually inhabit this bare planet. The American spacecraft Viking 1 was the first to land on Mars, in 1976, and the first to transmit images from the Martian surface. What it found was a dusty and cold planet that we would have to terraform in order to make it inhabitable.

However, it is difficult to actually travel to Mars and explore it. The biggest hurdle is the amount of time it takes to reach Mars. When Mars is closest to Earth, it is about 38 million miles away. To determine a launch window for Mars, there are many factors to consider. About every 26 months, Mars and Earth are positioned such that the time needed to travel between the two is minimized. The length of a launch window depends on the type of launch vehicle that is selected. A given launch vehicle is associated with a set of parameters that must be optimized, such as the amount of mass that can be carried given a certain target velocity. For a mission to Mars, lift-off is usually scheduled before an ideal launch day, but there needs to be acceptable conditions for the launch vehicle. A launched vehicle utilizes both the orbital velocity of the Earth (about 18 miles per second) and the velocity achieved by its rockets to move swiftly towards Mars. As it moves towards the orbit of Mars, it trades some kinetic energy associated with the velocity into potential energy. When it finally reaches Mars’ orbit, it will slow down enough to allow orbit capture. The total travel time from Earth to Mars is 150 days. Even with this fast travel time, there is still the issue of how a manned mission will get back to Earth, because once we are on Mars, we have to wait for a Martian launch window before sending a rocket back. Thus it is important to plan early when to take off from Earth as that will determine the takeoff date from Mars to Earth, since Mars and Earth are constantly changing their positions from one another.

To learn more about Mars, it takes tremendous effort and time. However, it would be worth it if we can terraform it and transform the planet into something we can inhabit that is similar to Earth.

Sources:

Zubrin, Robert, and Richard Wagner. "From Kepler to the Space Age." The Case for Mars: The Plan to Settle the Red Planet and Why We Must. New York: Free, 1996. 19-20 & 87-91. Print.
http://athena.cornell.edu/mars_facts/sb_launch_window.html

- Minami Makino