SpaceX delays first private launch to International Space Station "After reviewing our recent progress, it was clear that we needed more time to finish hardware-in-the-loop testing and properly review and follow up on all data," said SpaceX spokeswoman Kirstin Brost Grantham. While it is still possible that we could launch on May 3rd, it would be wise to add a few more days of margin in case things take longer than expected. As a result, our launch is likely to be pushed back by one week, pending co-ordination with Nasa," she explained. The main goals of SpaceX's flight include a fly-by of the ISS and a berthing operation in which the company's reusable space craft, the Dragon, will approach the ISS and the crew aboard the orbiting outpost will use the ISS robotic arm to help it latch on. The gumdrop-shaped Dragon capsule will carry 521 kilograms of cargo for the space lab and will also aim to return a 660kg load to Earth, Michael Suffredini, International Space Station program manager, said last week. SpaceX - owned by internet entrepreneur and PayPal co-founder Elon Musk - made history with its Dragon launch in December 2010, becoming the first commercial outfit to send a spacecraft into orbit and back. SpaceX and several other companies are competing to be the first to operate a private capsule that could tote astronauts and cargo to the ISS, after Nasa retired its shuttle program last year leaving Russia as the world's sole space taxi for astronauts. Other companies in the private space race include aerospace giant Boeing, the Nevada-based Sierra Nevada Corporation, and Washington state-based BlueOrigin LLC.