At the 67th annual International Astronautical Congress in Guadalajara, Mexico, SpaceX CEO Elon Musk unveiled the company’s plan to build a spaceship to travel Mars and perhaps even colonize the planet at some point with its SpaceX Interplanetary Transport System (ITS). Most of the ship, including its fuel tanks, are made with carbon fiber composites.

Materials scientist and Forbes contributing writer Sujata Kundu cites carbon fiber’s high tensile strength, design flexibility and low density as major benefits of employing composites in aircraft and spacecraft. She says strength will also play a major role in the ITS tanks.

“The strength of carbon fiber is required to withstand the high pressures that the tank could be subjected to,” Kundu wrote in her article on SpaceX’s announcement.

As Design News explains, the SpaceX rocket will have 42 separate engines that ignite with 28.7 million pounds of thrust. After exiting Earth’s atmosphere, the spaceship goes into orbit while the booster returns to Earth. Musk estimated it would take about 20 minutes for the booster to return.

However, according to Musk, in order for system to be cost-effective, it has to be reusable. Making the trip to Mars currently costs $10 billion per person. Thanks to modern technology, including the integration of composite materials, SpaceX believes it can cut that cost to only $200,000 per person.

“Combined with reusability, refilling makes performance shortfalls an incremental rather than exponential cost increase,” SpaceX explains on its website. The company chose between kerosene, hydrogen/oxgyen, and methane as forms of fuel, and eventually picked methane because it was the least complex and most energy-efficient option.

Musk says he hopes to have the first developmental spaceship ready to operate in about three years and that the first ship could be ready to depart in about 10 years. Eventually, up to 1,000 ships could be placed into orbit. Currently, the company is spending less than 5 percent of its resources on the Mars system. However, according to Musk, most of SpaceX could be working on the project in 2.5 years and the company could spend about $300 million a year on it.

For more information about the SpaceX Interplanetary Transport System, check out the video below: