(CNN) -- "Like the smell of a brand-new car" were the words of International Space Station astronaut Don Pettit on Saturday after he carefully opened the hatch and entered the Dragon capsule for his first glimpse inside.
Dragon connected with the station Friday, making history as the first private capsule to reach the orbiting spacecraft.
Pettit opened the hatch at 5:53 a.m. ET with Russian cosmonaut and station commander Oleg Kononenko by his side. The two men, wearing T-shirts, khaki shorts, goggles and masks gave the thumbs up to the camera after they floated inside.
The initial inspection went smoothly and ahead of schedule and the interior looked good, according to SpaceX, the private company that built and operates the Dragon.
Pettit later told reporters in a briefing from space that the interior is roomier than the Russian Soyuz capsule that carried him to the space station. He said "it looks like it carries about as much cargo as I could put in my pickup truck."
Dragon delivered more than 1,000 pounds of cargo, including food, clothing, computer equipment and supplies for science experiments.
After the crew unloads that cargo, they will reload the capsule with experiments and cargo for its return trip to Earth. Dragon is scheduled to splash into the Pacific Ocean several hundred miles west of California on May 31, according to NASA.
Pettit said the crew has packed most of what its plan to send back to Earth, which includes everything from trash to scientific research and experimental samples.
Dragon launched Tuesday from Cape Canaveral, Florida, aboard SpaceX's Falcon 9 rocket. NASA collaborated with SpaceX on every part of the mission and gave final authorization for the flight.
Dragon reached the station Friday and was "captured" by the station's robotic arm just before 10 a.m. ET. Over the next two hours, the crew maneuvered the arm to bring the capsule in to berth and attach it to the station.
The mission, hailed by NASA Administrator Charles Bolden as a step toward a new future of private innovation in the space industry, comes as government funding of the space program decreases.
It also marked the culmination of six years of preparation to bring commercial flights to the space station after the retirement of NASA's space shuttle fleet last year, which leaves the United States with no means of independently sending humans into space. NASA relies on the Russian space agency to ferry U.S. astronauts to orbit.
Without the shuttle, the United States also has limited capabilities to send supplies to the station and bring them back. Dragon fills a need in taking significant payload back and forth, Pettit said.
In December 2008, NASA announced it had chosen SpaceX's Falcon 9 launch vehicle and Dragon spacecraft to resupply the International Space Station after the shuttle's retirement. The $1.6 billion contract involves a minimum of 12 flights, with an option to order more missions for additional cost, according to SpaceX.
SpaceX was created by PayPal founder Elon Musk and is one of a few of private companies receiving NASA funds to develop the commercial transport of astronauts into space.
Musk has said the commercial program -- with fixed-price, pay-for-performance contracts -- makes fiscal sense for taxpayers and fosters competition among companies on reliability, capability and cost.
Astronaut Joe Acaba, also aboard the space station, called the mission a great first step in the commercialization of spaceflight, and Pettit agreed.
"Commercial spaceflight will blossom due to its own merits, and doesn't really hinge on one mission," Pettit said. "It will hinge on the viability of launching many missions over a long period of time and being able to provide useful commercial goods and services in the low-earth orbit arena."
SpaceX is now developing a heavy-lift rocket with twice the cargo capability of the space shuttle and hopes to build a spacecraft that could carry a crew to Mars.