The global space industry is reeling after three cargo disasters in less than a year have delivered a costly blow to efforts to supply astronauts aboard the International Space Station. The explosion of SpaceX's Falcon 9 rocket on Sunday also raised new questions about whether U.S. rockets are safe enough to start launching astronauts into space as planned in 2017. "It is unfortunately part of the business. The idea of 100 percent reliability is just not there," said Eric Stallmer, president of the Commercial Spaceflight Federation. "I am saddened at what happened today but tomorrow we will bounce back."The first in a series of accidents came in October, when Orbital lost its Cygnus cargo carrier due to an apparent flaw in the Ukrainian-made engine aboard its Antares rocket, which exploded shortly after lift-off from Virginia. In April, the Russian space agency lost communication with its ISS-bound Progress cargo capsule, which burned up on re-entry into Earth's atmosphere two weeks later. Then, SpaceX's Falcon 9 rocket exploded just over two minutes into its flight on Sunday, with the Dragon cargo ship and its 4,000 pounds (1,800 kilograms) of expensive gear falling to pieces in the Atlantic Ocean near the Florida coast. "This is a blow to us. We lost a lot of important research equipment on this flight," said NASA Associate Administrator Bill Gerstenmaier. Crew members living in orbit have plenty of food and supplies to last the next four months, NASA said, but officials admitted that no amount of planning could have prepared them for three major accidents in a row. Prior to Sunday, SpaceX had flown its Falcon 9 rocket 18 times in a row without incident. The company, headed by Elon Musk, the co-founder of PayPal and Tesla, also recently won the confidence of the U.S. Air Force to deliver national security payloads to space.SpaceX and Boeing are leading the U.S. commercial industry's race to send astronauts to low-Earth orbit by 2017. The U.S. has been unable to send astronauts to space since the 30-year shuttle program was retired in 2011, leaving the world's astronauts to travel aboard Russian Soyuz vehicles at a cost of $70 million per seat. "This doesn't change our plans," SpaceX president and chief operating officer Gwynne Shotwell told reporters after the accident. However, some experts were alarmed by the succession of problems - even if they are unconnected. The next cargo supply ship to fly to the ISS will be a Russian Progress capsule, blasting off on July 3. A Japanese HTV ship is launching in August, and Orbital - which, like SpaceX, has a billion-dollar-plus contract with NASA to supply the ISS -- is expected to launch again sometime in the fall after a one-year hiatus.