The second try was the charm for SpaceX. Launch of Falcon 9 was successful this time at 3:44 am Eastern Daylight Time (EDT). The first attempt on May 19 was aborted less than one second before liftoff. This time, the SpaceX Dragon capsule reached orbit and its solar arrays unfurled right on schedule.

The goal is for Dragon to berth with the International Space Station (ISS). It is full of supplies for the 6-person ISS crew. The next four days are full of various test maneuvers as Dragon proves that it can safely operate in the vicinity of the ISS. If all goes well, the ISS crew will grapple Dragon with Canada’s robotic arm and pull it into a docking port. Eighteen days later, Dragon will unberth the same way, reenter, and land in the Pacfic Ocean off the U.S. west coast.

A lot is riding on the success of this mission. NASA is paying part of the costs for developing the Falcon 9 and Dragon, as well as Orbital Sciences Corp.’s Antares rocket and Cygnus spacecraft — which have not launched yet — as part of its Commercial Orbital Transportation Services (COTS) program, also known as “commercial cargo.” NASA plans to buy cargo-to-ISS services from both companies now that NASA itself has no way to send cargo or crews to the ISS. Without the space shuttle, which was terminated last year, NASA has been relying on other partners in the ISS program to provide cargo and crew transportation services. Russia, Europe and Japan have cargo delivery systems. Only Russia can launch crews to the ISS and bring them home.

NASA also is paying for SpaceX and three other companies to develop “commercial crew” space transportation systems to take crews to and from ISS. Such services are not expected to be ready for several years yet, however.