Most of the new breed of space launch companies are working on innovative, totally reusable rocket systems that would return under full control, with wings like the shuttle or with retro-rockets like the Apollo moon landers. But these companies are concentrating for now on suborbital missions for tourists, which are much less demanding than actually getting to orbit.

SpaceX, which intends to go orbital from the start, does plan to make its rockets mostly reusable, but its designs are much more directly based on tried-and-true rocket designs of the past, with the addition of parachute systems to allow the individual stages to be recovered and refurbished after use. (For the Falcon 1, only the first stage is recovered.)

But this creates challenges in the development process: there is a limited amount of testing that can be done short of a full-blown launch attempt. With fully reusable flyback launch vehicles, on the other hand, it is possible to run flight tests incrementally, as X Prize winner Rutan did.

Over the course of a year, Rutan's suborbital SpaceShipOne flew several times, gradually increasing its speed and altitude, before it made its first attempt to reach space, and many lessons were learned and adjustments made during that process.

But with expendable rockets or passive-return rockets like SpaceX's, "you can test subsystems, but ultimately you have to test it all at once," said Henry Vanderbilt, founder of the Space Access Society, a group advocating the development of low-cost launchers. With such systems, Vanderbilt said, the slightest mishap can be catastrophic: "Any failure tends to leave a big hole in the dirt."

In Falcon 1's case, it was a small fuel leak on the engine, of unknown cause. This leak caused a fire, which burned through some control lines and triggered an engine shutdown. The crash is still under investigation by SpaceX and the U.S. Air Force, which paid for the satellite onboard and provided the launch facilities.

But that should not be taken as a sign that the design is faulty, Vanderbilt stressed: "If you look at the statistics of new launch vehicles, about 45 percent have had a catastrophic failure on the first flight," he said. And that includes workhorses like Russia's Soyuz, which has one of the best overall success rates to date in more than 30 years of flight, despite having had 12 failures in its first 21 flights.