SpaceX Dragon Cargo Ship Docks at Space Station

The SpaceX Dragon cargo capsule is seen with Earth in the background during docking at the International Space Station on March 3, 2013.
The privately built SpaceX Dragon cargo capsule is moved into its final position on the International Space Station's Harmony module with a bright Earth in the background in this view captured during the capsule's March 3, 2013, docking. The Dragon capsule is delivery cargo to the space station for NASA. (Image credit: NASA TV)

An unmanned commercial space capsule packed with precious cargo successfully linked up with the International Space Station early Sunday (March 3), making a flawless orbital delivery after overcoming a thruster glitch that delayed its arrival by a day.

The SpaceX-built Dragon cargo capsule docked with the space station at 8:56 a.m. EST (1356)  as the two spacecraft soared 253 miles (407 kilometers) over the Arabian Sea. NASA flight controllers performed the orbital link-up remotely by commanding the space station's Canadian-built robotic arm, which had latched onto Dragon three hours earlier, to attach the capsule to an available docking port.

"The Dragon is ours! Maneuvering it now on Canadarm2 to a docking port, will open hatches once secure," station astronaut Chris Hadfield of Canada wrote in a Twitter post.  "Look forward to new smells. Great!" [See photos of the Dragon's space station arrival]

Dragon reached the space station at 5:31 a.m. EST (1031 GMT), a full hour ahead of schedule. Two NASA astronauts, station commander Kevin Ford and flight engineer Thomas Marshburn, used the station's arm to grapple the capsule as it approached close to the orbiting lab.

SpaceX (short for Space Exploration Technologies) launched the Dragon capsule toward the space station on Friday (March 1), with the spacecraft riding the company's Falcon 9 rocket into orbit. While the launch was smooth, the Dragon capsule ran into trouble after it separated from the Falcon 9 rocket when three of four thruster pods did not activate as planned.

After several hours of troubleshooting, SpaceX engineers isolated the glitch to a pressurization problem in the thruster system and devised a fix that solved the problem. Because of the time needed for the fix, the Dragon capsule missed its initial rendezvous slated for Saturday (March 2).

The spacecraft's arrival on Sunday, however, went extremely smoothly. About four hours after the capsule was berthed to space station, astronauts opened the hatches between the two spacecraft to enter the Dragon, NASA officials said.

"Happy Berth Day, Dragon," SpaceX officials wrote in a Twitter post. The same message was emblazoned on the company's website.

"In solving the issues facing Dragon post-insertion, the team at SpaceX exhibited the ingenious engineering tenacity that has become a NASA hallmark, and further demonstrated the industry's readiness to perform the critical task of cargo delivery to low Earth orbit," Michael Lopez-Alegria, a former NASA astronaut and station commander who is now president of the Commercial Spaceflight Federation, said in a statement. "Congratulations to SpaceX and NASA for the successful berthing of Dragon this morning; I look forward to seeing Dragon back on Earth."

A SpaceX Dragon cargo capsule is perched at the end of the International Space Station's robotic arm after being grappled by astronauts on March 3, 2013, during the CRS-2 (SpaceX 2) cargo delivery mission. (Image credit: NASA TV)

Precious cargo for space station

The Dragon space capsule is packed with 1,200 pounds (544 kilograms) for the International Space Station, a haul that includes fresh food, science experiments and other vital equipment. The capsule is also carrying two grapple bars for the station's exterior inside an unpressurized "trunk" — a storage compartment in a cylindrical section of the spacecraft below its re-entry capsule. [How SpaceX's Dragon  Capsule Works (Infographic)]

This is SpaceX's third flight to the space station and second official cargo delivery under a $1.6 billion deal with NASA for resupply flights. Under that contract, the company has agreed to provide at least 12 Dragon supply flights to the space station. The Hawthorne, Calif.-based firm was founded in 2002 by billionaire entrepreneur Elon Musk to develop commerical rockets and spacecraft.

"I remember exactly where I was the very first time I ever heard of this scheme …when I was a young astronaut, and I said, 'We're going to do what?'" Ford told Mission Control during the docking operation. "That was when it was an idea and now it is starting to become routine. "

SpaceX launched its first Dragon to the space station last May during a demonstration flight, and followed that success with an official cargo delivery in October.

This NASA graphic shows the location of SpaceX's Dragon space capsule after its docking with the International Space Station on March 3, 2013. The Dragon capsule is delivering cargo for NASA under the CRS-2 (SpaceX 2) mission. (Image credit: NASA)

Cargo missions for NASA

NASA has a similar cargo delivery deal with the Virginia-based Orbital Sciences Corp., which will use its new Cygnus spacecraft and Antares rocket to launch eight cargo missions under a $1.9 billion contract. The first Antares and Cygnus test flights are expected later this year.

With the space shuttle fleet retired, NASA is relying on private spacecraft like SpaceX's Dragon capsules to fly cargo — and ultimately astronauts — to the International Space Station. Currently, NASA is dependent on Russia's Soyuz spacecraft to launch American astronauts into space.

SpaceX is one of four companies developing manned spacecraft under NASA's commercial crew program. Its manned spacecraft is an enhanced version of the Dragon spacecraft designed to fly seven people to the station and return them to Earth at mission's end.

The Dragon space capsule that arrived at the space station Sunday will stay linked to the space station until March 25, when it will be plucked free using the robotic arm and released back into space.

Unlike the unmanned Russian, European and Japanese cargo spacecraft that serve the space station, SpaceX's Dragon capsules have a heat shield that allows them to re-enter Earth's atmosphere to return science experiments and other gear. This Dragon is expected to return about 2,700 pounds (1,210 kg) of gear to Earth for NASA when it splashes down in the Pacific Ocean off the coast of Baja California.

"What a fantastic day," Ford radioed Mission Control of the smooth Dragon rendezvous Sunday. "Obviously the vehicle is beautiful, the station is beautiful, the Canadarm2 is beautiful … the prettiest thing of all was the dance."

Visit SPACE.com for complete coverage of SpaceX's Dragon mission to the International Space Station.

This story, originally published at 9:20 a.m. ET, was updated at 2:46 p.m. ET to include new details about the station crew's ingress into the Dragon spacecraft.

SPACE.com Staff Writer Miriam Kramer contributed to this report. You can follow SPACE.com Managing Editor Tariq Malik on Twitter @tariqjmalik. Follow SPACE.com on Twitter @Spacedotcom. We're also on Facebook & Google+This article was first published on SPACE.com.

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.

Tariq Malik
Editor-in-Chief

Tariq is the Editor-in-Chief of Space.com and joined the team in 2001, first as an intern and staff writer, and later as an editor. He covers human spaceflight, exploration and space science, as well as skywatching and entertainment. He became Space.com's Managing Editor in 2009 and Editor-in-Chief in 2019. Before joining Space.com, Tariq was a staff reporter for The Los Angeles Times covering education and city beats in La Habra, Fullerton and Huntington Beach. In October 2022, Tariq received the Harry Kolcum Award for excellence in space reporting from the National Space Club Florida Committee. He is also an Eagle Scout (yes, he has the Space Exploration merit badge) and went to Space Camp four times as a kid and a fifth time as an adult. He has journalism degrees from the University of Southern California and New York University. You can find Tariq at Space.com and as the co-host to the This Week In Space podcast with space historian Rod Pyle on the TWiT network. To see his latest project, you can follow Tariq on Twitter @tariqjmalik.