The way we send stuff into space hasn't changed much in the past 50 years: Multi-stage rockets spend their fuel and dump their lower sections as garbage.

That's too wasteful for Elon Musk and his SpaceX company.

During the next SpaceX takeoff, planned for either Jan. 6 or 7, SpaceX will try to keep the base rocket section in good shape by landing it -- standing straight up -- on a barge floating in the ocean.

How challenging is that? Consider three things.

One, that rocket section, called Falcon 9, is 14 stories tall and will be climbing at nearly 1 mile per second. Trying to stabilize that rocket to guide it back down is "like trying to balance a rubber broomstick on your hand in the middle of a wind storm," SpaceX says.

Two, in previous attempts at reentry, the company aimed at a spot that was 10 kilometers wide. Now it has to hit a bullseye that's 10 meters wide.

Three, that bullseye is moving. Remember, it's a floating barge. The "autonomous spacesport drone ship" isn't anchored to the ocean floor, so it'll use engines to keep it steady.

Landing a fighter jet on an aircraft carrier seems easy by comparison.

The trick will be to use Falcon 9's rocket bursts to slow it down and fins to keep it straight. SpaceX estimates there's, at most, a 50% chance it could pull this off this time around.

Why do it? Creating a reusable rocket would vastly reduce the cost of space travel. It's never been achieved yet, and that's partly why it's so expensive. Right now, it easily costs $2,000 or more to send a pound of anything into space. Musk wants to reduce that below $1,000.

And it won't be the last shot. The company plans to test this more than a dozen times in 2015.

This launch, which was previously scheduled for mid-December but got pushed back, is an unmanned cargo trip to the International Space Station for NASA.

There's extra pressure on this one, though. The private sector space industry experienced a tragic October. This is the first major launch since the fatal crash of Virgin Galactic's SpaceShipTwo and the exploding unmanned Antares rocket belonging to Orbital Sciences Corporation (ORB).

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