Space Exploration Technologies Corp. had yet another grim reminder of just how difficult it is to get into space when its third consecutive rocket failed to reach orbit over the weekend.

The Hawthorn-based space company said that the Falcon I rocket failed to reach orbit Saturday because the first stage failed to separate as required less than two minutes into the flight, causing the rocket to fall back to Earth.

This latest failure is a setback to SpaceX’s ambitions of providing NASA a reliable commercial alternative to its own vehicles for delivering cargo to the International Space Station. Military planners also have been considering the Falcon for launching its smaller, less-expensive satellites and to test new technologies in orbit.

The rocket’s payload on Saturday included small Trailblazer satellite for the Pentagon and two small NASA satellites. The launch was held at the U.S. Army’s Reagan Test Site on Omelek Island in the Kwajalein Atoll, about 2,500 miles southwest of Hawaii.

This marks the third time in as many tries that the most prominent, privately funded space company, started by PayPal founder Elon Musk, has suffered a launch failure. The first Falcon I launch barely lifted off the launch pad, while the second failed to reach orbit because of a rocket problem, according to the company.