Traveling to Mars is no longer just a theoretical idea. A proposed plan by Dennis Tito, the world's first paying space tourist, would get astronauts within 100 miles of the red planet's surface. Tito's plan, which he unveiled before the House subcommittee on space, is intriguing for a number of reasons - particularly when it comes to the price tag.

In addition to money that NASA is already spending on current rocket and spacecraft development programs, Tito says only $1 billion would be needed to complete the fly-by mission, and that would be contributed as such: $300 million from private donors, and $700 million from the government.

Tito's plan, called “Inspiration Mars,” is also intriguing when it comes to another valuable resource - time. The mission would have to take advantage of next alignment of Earth and Mars, which occurs in 2018 (requiring a 2017 launch date for the 501-day trip). That means, of course, that time is of the essence. Miss that window and we'll have to wait another 15 years to take advantage of the orbital dynamics of the planets, which significantly reduce the distance and cost of the trip. 

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