NASA's dream of returning manned space flight to American soil is one step closer with its initiation of commercial space flights and training.

The agency announced that it had selected four veteran astronauts to fly the first commercial crew vehicles. The announcement comes 50 years after America received the first images of Mars from space.

The four astronauts chosen — Robert Behnken, Sunita Williams, Eric Boe and Douglas Hurley — are set to launch in 2017. NASA's announcement allows the astronauts to officially commence training.

The commercial crew endeavor is focused on not only landing humans on Mars in the near future, but also on bringing space exploration back to the United States and away from the program's recent reliance on Russia.

"There are real economic benefits to bolstering America's emerging commercial space market. We have over 350 American companies working across 36 states on our commercial crew initiative. Every dollar we invest in commercial crew is a dollar we invest in ourselves, rather than in the Russian economy," said Charlie Bolden, NASA administrator.

Currently, NASA must pay Russia $71 million to fly one American astronaut to the International Space Station aboard the Soyuz spacecraft. The move to American-made space transportation should lower that cost to $58 million. On top of that, each mission will be able to carry four crew members instead of three and also allow for 220 pounds of materials to be taken to the ISS to bolster the scientific research done there.

The agency will be working with U.S. companies to design "crew transportation vehicles" so that NASA will be able to put more effort into advanced technologies, the Orion Spacecraft and the Space Launch System that are geared toward getting humans into deep space.

"[This is] all part of our ambitious plan to return space launches to U.S. soil, create good-paying American jobs and advance our goal of sending humans farther into the solar system than ever before," Bolden said.

President George W. Bush halted the space shuttle program in 2004 on the recommendation of the Columbia Accident Investigation Board. Many in the public, including Bolden, endorsed the decision.

With NASA's goals of putting people on Mars by the 2030s, however, Bolden made clear that the agency needs to step up the attention it gives to deep space and the science done aboard the space station. The project, called Journey to Mars, was authorized in 2010.

"I cannot think of a better way to continue our celebration of independence this July than to mark this milestone as we look to reassert our space travel independence and end our sole reliance on Russia to get American astronauts to the International Space Station," Bolden said.