With Space Exploration Technologies getting ready to send its gumdrop-shaped Dragon capsule into orbit atop a Falcon 9 rocket sometime this week, the company's CEO Elon Musk tried to underplay the expectations from the flight, saying that that the Dragon has only about a "60 percent or thereabouts" chance of coming back down successfully.

To work out the success chances, the 39-year-old dot-com millionaire said rather impassively that he estimates the Falcon 9's chances of success at around 90 percent; and the Dragon's chances of getting into orbit and back down to its Pacific Ocean landing zone successfully at around 70 percent.

As such, multiplying together the two probabilities, Musk said that the chances of Dragon's successful come back are around 60 percent.

Nonetheless, hoping for a 100 percent success, Musk also added that the SpaceX engineers have tried to maximize the Dragon's chances by going for a tad of "overkill" on the carbon-based heatshield material, called PICA-X.

Musk has apparently tried to play down the chances of success of the forthcoming flight because the Falcon 9's debut launch in June was a nearly flawless one, and the expectations are notably higher for the second launch.

However, referring to the statistics pertaining to launches, Musk noted: "Historically, the track record for the second launch of a new vehicle is not that great. The statistics improve dramatically around launch 3 and 4."