The SpaceX Dragon commercial cargo craft after it was grappled and connected to the International Space Station, May 25, 2012. (AP/NASA)
The SpaceX Dragon commercial cargo craft after it was grappled and connected to the International Space Station, May 25, 2012. (AP/NASA)

Less than 24 hours after the Dragon capsule docked with the International Space Station, astronauts opened the hatch and floated into the first private spacecraft to ever reach their orbiting outpost.  

NASA astronaut Don Pettit said there was something familiar about the Dragon capsule, which was developed by the private company SpaceX.

"The smell inside smells like a brand new car," described Pettit, as he inspected the vehicle.

Pettit was among the astronauts who later spoke to reporters from inside the capsule.

"I'm very pleased," he said.  "It looks like it carries about as much cargo as I could put in my pick-up truck, and it's roomier than a [Russian] Soyuz, so flying up in a human-rated Dragon is not going to be an issue."

Video of ISS crew members entering the SpaceX Dragon capsule

ISS Astronauts enter the SpaceX Dragon Capsule

SpaceX says it designed Dragon with crew-carrying capability in mind.  The California-based company is developing seating, a launch escape system and life support systems for the capsule.

SpaceX officials say they hope to send people into space aboard the Dragon spacecraft within three years.  The United States does not have a way to ferry astronauts to the space station since it retired its shuttle fleet last year, so NASA would like to rely on private companies to handle that task.

But for now, Dragon is a cargo ship.  It is carrying more than 500 kilograms of non-critical supplies on this mission, such as commemorative patches, clothing, meals and student experiments.  After astronauts unload the craft, they will fill it with used equipment to be returned to Earth May 31.  Only SpaceX's Dragon capsule and the Russian crew-carrying Soyuz craft can return items to our planet.    

The U.S. space agency has invested nearly $400 million in SpaceX's commercial cargo capabilities.

SpaceX made history when Dragon became the first commercial vehicle to dock with the International Space Station, a feat that had only been accomplished by the governments of Russia, the U.S., Europe and Japan.

Gallery of ISS/Dragon Docking

Astronaut Pettit compared the Dragon's arrival to the completion of the railroad that made the western frontier of the United States far more accessible.  Pettit said it did not matter who was responsible for hammering down the commemorative golden spike that signaled that the railroad was finished.

"The important thing is to remember that the railroad was completed and was now open for use to help settle the western frontier," Pettit said.

The U.S. space agency is looking to frontiers beyond low-Earth orbit, such as asteroids or Mars.  NASA is investing in private companies to handle low-Earth orbit transportation so that the space agency can focus on developing the next generation of space vehicles.