On January 10, 2015, SpaceX launched Commercial Resupply Services (CRS) mission number 5, or CRS-5, on a special Falcon 9 launch vehicle. This particular vehicle included a first stage that was intended to be safely returned intact in order to demonstrate reusability.

The primary mission appears to be a success in that SpaceX delivered cargo to the International Space Station (ISS) as specified in its CRS contract with NASA.

During ascent, after separation from the upper stage over the Atlantic Ocean, the nearly empty first stage began to fall toward Earth, as did its predecessors.

However, in this case, the stage carried additional hardware, avionics and propellant in order to allow a powered and guided descent to a waiting 50-meter by 90-meter (roughly the size of a football field) autonomous floating platform.

Apparently, all went well, right up until the final few seconds as the stage approached the platform.

The sequence of events was executed as expected. After release of the upper stage, rockets and hydraulically-actuated fins on the first stage were used to control orientation and descent of the roughly 40-meter long rocket body to a vertical landing on the waiting platform.

Successfully landing vertically on a floating or land-based target is quite risky. Descent must be slowed to almost zero as the landing gear touch the platform. At the same time the vehicle must be precisely vertical. Any small errors in orientation or speed will result in failure.

Unfortunately, the descent did not go quite as planned and the stage crashed on the platform. SpaceX's Elon Musk tweeted: "Rocket made it to drone spaceport ship, but landed hard." He added "Close, but no cigar this time."

He blamed the hard landing on a failure of the four steered descent fins. Apparently, the hydraulic actuators depleted all of the needed fluid just before landing.

Launch vehicle experts generally agree that reusability will lead to lower launch prices and better access to space. Others have tried to achieve lower-stage reusability, but most have failed for a variety of reasons. SpaceX has again demonstrated that the challenges are great.

Clearly, there is much to be learned about the technologies and from the failures. For space professionals who are involved in developing reusable launch systems and want to learn more, Launchspace has a focused two-day course, "Introduction to Reusable Launch Vehicles," that can be presented at your facility.