Now even the United Arab Emirates is launching a rocket to Mars. Some think there's a new space race to Mars involving the U.S., Russia, China, and others.
Space expert Keith Cowing says it's not a race.
"If there's a space race to Mars we already won a long time ago; we're just doing victory laps."
Cowing says the Russians probably can't afford to put men on Mars and the Chinese are ten years behind in technology.
"I'm not sure who's going to be the first to do it, but I'm pretty sure it'll be Americans."
Cowing says one thing's new; other countries aren't copying NASA technology, they're copying SpaceX.
"The Russians could do it, but they'll never have the finances to accomplish it; China someday will be able to but they're a decade or so behind any capability we have."
Cowing says a lot of the work going into the U.S. effort to further explore Mars is NASA, but other countries are now copying SpaceX technology. There's a narrow window this year in which missions to Mars can launch and if that's missed it'll be a couple of years before the planets align just right again.