An astronaut and cosmonaut floated into the Space Station's first inflatable habitat today

NASA astronaut Jeff Williams and Russian cosmonaut Oleg Skripochka floated into the International Space Station's newest habitat Monday, possibly paving the way for private space stations in the years to come.

The two space station crewmembers entered the habitat — named the Bigelow Expandable Activity Module (BEAM) —- at 4:47 a.m. ET Monday after Williams helped to expand the module on May 28. 

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According to NASA, Williams said the BEAM looked "pristine" from the inside. Williams wore a mask and headlamp when entering the habitat, which was reportedly about 44 degrees Fahrenheit on the inside, and he took an air sample for analysis. 

The crewmembers may also enter the habitat on Tuesday and Wednesday to do more testing, and the hatch linking the 7-foot-long BEAM to the rest of the Space Station will be closed after each excursion is over.

The habitat itself was built by Bigelow Aerospace, a private space company with the goal of eventually fabricating modules or even full space stations that can get packed up and expanded once in orbit.

To be viable, such stations will need to offer astronauts, and perhaps someday, scientists and even tourists, similar levels of protection against the many formidable hazards of operating in space as the current Space Station does. 

"This first test of an expandable module will allow investigators to gauge how well the habitat performs and specifically, how well it protects against solar radiation, space debris and the temperature extremes of space," NASA said in a statement.

The compact nature of expandable modules could free up more room on a rocket for other important hardware or experiments that also need an expensive ride to space. 

Because of their small size during launch, the habitats could even be a key component of a mission to Mars.

The BEAM is expected to stay attached to the Space Station for two years before being jettisoned from the outside of the orbiting laboratory.

During that time, astronauts will take readings of the habitat's interior about three to four times annually, according to NASA. Those readings will focus on monitoring the BEAM's structure, temperature, radiation and pressure. 

Bigelow Aerospace is dreaming big when it comes to inflatable habitats in space.

The private company — founded by hotel magnate Robert Bigelow — has suggested that they would like to fly an even larger module to the Space Station in the future, which could serve as a tourist destination and additional square footage for experiments.

If Bigelow gets its way, this "timeshare" could happen as soon as 2020. 

Bigelow has also suggested that companies could have their own branded space stations using their expandable habitats. 

"We would love to see Disney have a Disney space station," Bigelow said during a press conference in April.