Space Matter: Getting to Mars

Space Matter is a weekly column that delves into space science and the mechanics of spaceflight. From the latest discoveries in the universe around us to the fits and starts of rocket test flights, you’ll find analysis, discussion, and an eternal optimism about space and launching ourselves into the cosmos.
We’ve been talking quite a bit about going to Mars, but why? Let’s say you agree with the basic idea that we need to get back out into space (if you don’t, why are you reading a column called Space Matter?) but you don’t quite know why we keep focusing on Mars. Why not Venus? After all, when it’s closest to Earth in its orbit, it’s nearer to us than Mars ever is. And why don’t we go back to the moon while we’re at it?
The short answer for Venus is that the atmosphere is toxic. Yes, the Martian atmosphere is thin and not breathable, and generally when you’re not on Earth, you’re best operating under the assumption that everything out there is actively trying to kill you—but Venus would actually do its best to kill you. Think of the entire planet’s atmosphere as acid soup. What’s more, the atmospheric pressure of Venus is much, much higher than Earth. There’s a reason we don’t know a lot about what’s under its cloud cover—landers are crushed within just a few hours because of surface pressure. Humans would not fare well, even in spacesuits, especially considering all the trapped heat making Venus the hottest planet in the solar system—hotter even than Mercury, which is much closer to the sun.
Photo courtesy of NASA/NSSDC Photo Gallery
And the moon? We will go back to the moon, for certain. If we’re going to have a permanent presence on Mars, we’ll likely establish some sort of permanent presence on the moon as well. It’s easier to get to Mars from the moon; we don’t have to deal with the extraordinary efforts it takes simply to escape our planet’s atmosphere. The moon is on our list, but we’ve been there before. It’s good to set our ambitions on something new.
So, Mars. It’s the logical choice. Now, how do we get there?
NASA is developing the SLS (Space Launch System), and when it’s finished, it will be the world’s most powerful rocket. SLS is specifically being designed to take us deeper into space than we’ve ever been. The rocket will be multipurpose; it can take us into low Earth orbit, but adding an additional stage (the Exploration Upper Stage) will take us to the moon and beyond.
Photo courtesy of NASA/MSFC
Private companies such as SpaceX are also working on their own methods to get to Mars. Elon Musk has outlined his plans to get SpaceX to Mars, and to arrive there first. In fact, he wants to start building a colony on the red planet, and Musk is planning on using the profits from his satellite Internet business to do it.