Ever since NASA retired the Space Shuttle three years ago, the United States has had to arrange for Russian rockets to deliver American astronauts to the International Space Station (ISS). While the current method wasn't meant to be permanent, recent political differences between the U.S. and Russia have only accelerated the long-term plane: space taxis. 

The Seattle Times reports that two companies are in the running to be awarded a contract to build NASA's next generation of manned space vehicles that would not only deliver astronauts to the ISS, but make commercial flights into space as well. The contract would award the winner with $3 billion in funding in order to develop the new space taxis by 2017. While that doesn't leave much time to complete the project, it shows just how committed NASA is to ending its reliance on the Russians to get American astronauts into space. 

Currently, the two companies in the lead for NASA's contract are SpaceX and Boeing. SpaceX is Elon Musks other company. The Tesla founder also owns SpaceX, and winning this NASA contract would be a huge victory for his young company, especially over industry mainstay Boeing. Were Boeing to win, it would come as no surprise since they have been working with NASA for more than 50 years. 

There is also a third firm hoping to win the bid, Sierra Nevada, though no one seems to really consider them as having a legitimate shot at winning NASA's contract this time around. 

According to one analyst, Loren Thompson, "Boeing is the safe choice, SpaceX is the exciting choice and Sierra Nevada the interesting choice." 

The reason SpaceX and Boeing are viewed as having an edge over Sierra Nevada is because NASA has requested and funded redesigns of their proposed designs for the space taxi. Some have suggested that NASA may simply split the contract between SpaceX and Boeing instead of awarding the whole contract to either of them. NASA also confirmed this was a possibility, reports the Times.

Musk and SpaceX seem to have some very ambitious plans for space exploration, perhaps even more ambitious of those than NASA. 

"The reason I haven't taken SpaceX public is the goals of SpaceX are very long term, which is to establish a city on Mars," said Musk. Wow. According to the Times, Musk did not respond to requests for comment on SpaceX's chance to win the NASA contract.