And the contract for National Aeronautics and Space Administration (NASA)'s space taxi goes to ... Boeing Co. and SpaceX.

The debate among experts and NASA officials about who -- Boeing, SpaceX or Sierra Nevada Corporations -- would get the coveted space taxi was reported on last month. At the time the article was written, Boeing and SpaceX had just been awarded a joint contract. 

Boeing Co. and SpaceX were in the lead to secure the deal. The multi-billion dollar contract meant transporting astronauts to and from orbit to the International Space Station (ISS) for NASA, The Wall Street Journal reported. Boeing's proposed capsule was seen as the least risky option.  

However, SpaceX has also been a NASA favorite and delivered lower costs and effective methods. SpaceX is a science, exploration and outer space shipping company.

NASA administrator Charles Bolden stated at the Kennedy Space Center in Florida that this venture is one of the "most ambitious and exciting" plans for their company, The Washington Post reported.

With NASA, Boeing and SpaceX's space venture, NASA will no longer have to rely on Russia.

Since the retirement of NASA's space shuttle, three years ago, Russia has been ferrying U.S. astronauts to and from the ISS. The trip has been costly: Russia currently charges $71 million per seat. Within a year, NASA has paid $400 million to Russia for the taxi rides.

If the schedule of NASA's space taxis stay on task, SpaceX and Boeing could launch as early as 2017.

Both Boeing and SpaceX have a lot to prove. The space taxi contract is subject to the completion of certain safety regulations, certifications and development efforts for Boeing's CST-100 Capsule, and SpaceX's Dragon Capsule, Time reported. These certification "milestones" that both space age companies have to complete are: a baseline review, a design review, a flight test readiness review, an operational readiness review and a certification review.

Once the two companies are approved by NASA, then they can be allowed for two to six human missions to deliver cargo, and a crew of up to four to the ISS.

These space taxis could allow NASA to double the amount of time spent on scientific research. The space capsules will also serve as a "life boat" for crew members, keeping them safe up to 210 days, in the event of an emergency. 

Not everyone is happy NASA's choice, namely Sierra Nevada Corp.

It was reported that the company -- for the first time in its 51-year history -- filed a major protest against NASA. In the protest, Sierra Nevada contends that the space taxi contract should have more consideration.  

Sierra Nevada Corp. felt it necessary to file the protest with the Government Accountability Office, under the grounds that they were "serious questions and inconsistencies in the source selection process." The company further stated that their proposal was the second lowest priced when compared to Boeing and SpaceX. Boeing's contract is worth worth up to $4.2 billion, while SpaceX's is valued at $2.6 billion.

NASA has not given a specific reason as to why both companies were awarded different amounts for similar jobs.  

Sierra Nevada proposed using a reusable miniature shuttle, a "space plane," what they called the "Dream Chaser." The craft "provides a wider range of capabilities and value," Sierra Nevada mentioned via a statement.

A NASA spokeswoman declined to comment.