SpaceX founder Elon Musk has a very ambitious plan: to send men to Mars by 2022. Many of you may not know about SpaceX. Basically, SpaceX is a privately-owned company based on the principles of reusability. Right now, they are extensively testing the rocket Falcon 9. Falcon 9 is a two-stage rocket capable of getting up to 50,000 pounds into low earth orbit (LEO). In 2012, Falcon 9 was the first spaceship from a privately-owned company to reach the International Space Station. Falcon 9 is innovative because it is 100% reusable. Unlike all other rockets, this one doesn’t require any parachutes to land; all parts of the rockets land safely without parachutes and can be used again. This makes everything less expensive because the can land back on the launch pad, refuel, and launch again.
SpaceX plan to make a city on Mars, not just an outpost on Mars for a few scientists to live on. They want to make a city on Mars with thousands and thousands of people, and, eventually, they say they want to terraform Mars. You may ask “why Mars?” There are many other planets, but why Mars? Why not Venus? It is closer to Earth and it has been called “Earth’s twin sister.” You could try Venus, except for the fact that it reaches 863 degrees Fahrenheit. It also has acid rain capable of burning through your skin. Also, the atmosphere would crush you. Mars, on the other hand, is a lot more like Earth. It has a 24 and half hour day and a very similar axis tilt. It’s year is not that much longer than ours, only about twice the length of a year here. That seems long, but remember, one year on Pluto is 248 Earth years long.
From this, Mars seems perfect. That is not entirely true. The average temperature on Mars is -82 degrees Fahrenheit. That’s cold. It also does not have breathable air, so we would have to wear full spacesuits since Mars has less than 1% of Earth’s atmospheric pressure. That also means that even if it were warm enough, there would never be liquid water on the surface. Mars only has one-third of Earth’s gravity, so bones and muscles would decay. Radiation would also be a problem. Mars has such a thin atmosphere that a prolonged stay on the planet would greatly increase the chance of developing cancer. Despite these problems, SpaceX is still ambitious to get to the Red Planet.
Furthermore, getting to Mars would be costly. Going to Mars would probably cost around 10 billion dollars per person. Pretty much no one can afford that, and of the few who could, they might not want to go. SpaceX wants to get costs down to 200 thousand US dollars, which is the average cost of a house in the USA. Then many more people could afford to go, some of whom would want to. So, all SpaceX needs to do is get a ticket to Mars down to 200 thousands dollars a person and Mars could be ours. The question is how do we get this done.
SpaceX says the four key elements to get the cost down are reusability of parts, refueling in space, fuel production on Mars, and the right propellant. Elon Musk believes the most important of these is full reusability, which is already being developed and tested by Space X. Once that is complete, all that needs to be done to increase the scale of this. Reusability would lower the cost because we would not need to build a new spaceship for every launch. To put this in perspective, imagine if your car were single-use. Every time you want to go somewhere, you would need a new car. Very few people would buy cars if this was the case. The Earth to Mars Transfer (ETMT) vehicle would not be able to be used as much because of the Earth and Mars rendezvous period only occurs about every two years. The tanker and booster stages could be used a lot more times, so the plan is to launch to ETMT vehicle into LEO and use the booster and tanker over many launches to transport fuel and resources up to the orbiting ETMT unit. The two rocket components would land at the launch site and refuel and could probably relaunch within hours. The ETMT would then wait for the Earth to Mars rendezvous when 100 people would be taken up to the ETMT and then to Mars. By the time of the rendezvous, there could be hundreds of ETMT units fully fueled waiting for the transfer window to go Mars
The ETMT would take 3-5 months to get to Mars before using very advanced heat shields to aerobrake in the Martian atmosphere and land at the colony. The ETMT is now completely out of fuel and must get back to Earth, so they must refuel on Mars with whatever is available there. The best options are kerosene, liquid hydrogen, or methane. These are the common fuels used by spacecraft today. Kerosene is very complex and would be nearly impossible to make on Mars unless you bring along extra materials. Hydrogen would not be the best choice since it is very expensive and requires lots of energy to store. That leaves methane, which is very easy to make on Mars. It is very inexpensive, and it does very little damage to the storage tanks so storage tanks can be reused. All that is required to make the fuel is carbon dioxide and water. There is plenty of carbon dioxide in the atmosphere and underground ice for the water. The ETMT could then be refueled and sent back to Earth to be used again.
Elon Musk says that within 40-100 years of the first launch, there could be up to 1 million people on Mars, enough to make a self-sustaining city there. That is when we truly become a multiplanetary species. All we need to do for the next big step in the human journey is to lower the cost of the trip to Mars and go there.