Space enthusiasts get excited: SpaceX's new Merlin rocket engine has been approved for use. Gaining this qualification wasn't easy. The Merlin rocket engine was subjected to a total of 28 tests amounting to 1,970 seconds of total test time. SpaceX has said that this amounts to 10 full missions of use.

The Merlin 1D successfully performed every test throughout this extremely rigorous qualification program. With flight qualification now complete, we look forward to flying the first Merlin 1D engines on Falcon 9's Flight 6 this year.

The Merlin will see its first use launching a weather and communications satellite into low-Earth orbit. After that, Merlin will be used to launch a satellite into geosynchronous orbit. The Merlin engine has been in development for about two years.