When you're planning a trip, one of the most important things to remember is factoring in the transportation cost. And that's especially true for space travel.

Traveling to Mars is going to be expensive, so NASA is betting on the future development of a more efficient and less costly type of propulsion to get there.

It's called solar electric propulsion (SEP), and it's sort of like the Tesla version of spacecraft.

SEP's major advantage is that it's engine uses 10 times less propellant than typical chemical propellants. Most of its power comes from solar arrays that unfurl after launching and convert solar energy into electricity to power the thrusters and any scientific instruments on board.

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