SpaceX prepares to take the biggest step towards affordable space travel: Soft landing the Falcon 9 rocket (updated)

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SpaceX, Elon Musk's poster child of the commercial space travel revolution, is about to attempt the first ever soft landing of a heavy space launch vehicle. On March 16, SpaceX mission CRS-3 will lift off from Cape Canaveral on a resupply mission to the International Space Station. Usually, the massive primary stage of the rocket would fall into the Atlantic ocean after launch -- but in this case, it will sprout some metal legs and use what's left of its rocket fuel to slowly return to Earth. This is perhaps the single most important step in SpaceX's stated goal of reducing the cost of space travel by a factor of 10, eventually leading to the human colonization of Mars.

One of the primary reasons that the human exploration of space is moving so slowly is cost. Yes, you can argue that space agencies like NASA and ESA should receive more funding, but at the end of the day it's still excruciatingly expensive for humanity to send stuff into space. For heavy lift vehicles, which are required to lift large satellites, equipment, and supplies into space, it costs somewhere in the region of $10,000 to lift a single pound ($22,000/kg) into orbit around the Earth. It costs even more if you want to propel that mass out of the Earth's gravity and over to Mars. For sending astronauts into space, though, NASA currently pays around $70 million per seat aboard the Soyuz space capsule. (A crewed version of SpaceX's Dragon capsule, DragonRider, is in development, which will reduce the cost per seat to $20 million -- but it won't launch until 2015 at the earliest.)

Now, it's always going to be expensive to lift stuff off the Earth's surface (blame gravity!), but there are some big changes we can make that will reduce the cost significantly -- such as re-using the launch vehicle. Currently, for all space launch vehicles, the initial rockets and fuel tanks are jettisoned -- usually into the ocean, never to be seen again. This is incredibly wasteful; according to the Space Development Steering Committee, those rockets cost in the region of $100 million, and we throw them away after a single use. Enter SpaceX's reusable launch vehicle (RLV) technology.

SpaceX originally debuted its RLV tech on the suborbital Grasshopper rocket in 2013 (video above). If the tests were successful -- which they were -- the plan was to take the same tech and scale it up to the full-size Falcon rocket. Basically, after the first stage detaches from CRS-3, it will use its Merlin rocket engines to slowly return to Earth. For this flight, the first stage will still land in the water -- but once SpaceX is confident that it can do so safely, future launches will see the first stage fly all the way back to to the launchpad. After that, SpaceX will start bringing the second stage back to the launchpad, too.

The eventual goal, according to SpaceX, is to create a launch system that is reusable within "single-digit hours." Basically, SpaceX would give these rockets a quick once-over, fill them back up with fuel... and off they go again. The fuel is still very expensive, but it's nothing compared to the cost of the hardware. If everything goes to plan, the total cost per pound to launch into Earth orbit could drop to $500 or less -- one twentieth of what today's unreusable rockets cost. Suffice it to say, if SpaceX manages to undercut every other space launch company in the world -- including the Russian and Chinese governments -- it could suddenly find itself in a very powerful and lucrative position.