In rocketry, what goes up usually comes down in pieces. 
 
 The cost of getting to orbit is exorbitant, because the rocket, with its multimillion-dollar engines, ends up as trash in the ocean after one launching. 
 
 Elon Musk, the chief executive of the Space Exploration Technologies Corporation, better known as SpaceX, likens the waste to throwing away a 747 jet after a single transcontinental flight. 
 
 “Reusability is the critical breakthrough needed in rocketry to take things to the next level,” Mr. Musk said in October during a talk at the Massachusetts Institute of Technology. 
 
 On Tuesday, his company hopes to upend the economics of space travel. 
 
 At 6:20 a.m. Eastern time, one of SpaceX’s Falcon 9 rockets is scheduled to lift off from the Cape Canaveral Air Force Station in Florida on what is otherwise a routine unmanned cargo run to the International Space Station. ||||| Photo by SpaceX 
 
 Update, Jan. 6 at 15:45 UTC: The launch was scrubbed at T-1:21 due to a problem with an actuator in the upper stage that controls the thrust vector; the direction the motors thrust to keep the rocket on course.The next launch attempt will be Friday at 10:09 UTC (05:09 Eastern). 
 
 Phil Plait Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies! 
 
 Yeah, just writing that headline was weird. 
 
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 Still, it’s true. At 11:20 UTC (06:20 Eastern) Tuesday morning, SpaceX will attempt to launch a Falcon 9 rocket with a Dragon capsule to the International Space Station. The Dragon has nearly two tons of supplies for the astronauts on board. This will be the fifth such resupply mission by SpaceX. 
 
 But it’s what happens a few minutes after launch that has me very interested: After the initial separation, the first stage booster of the F9 will attempt a vertical landing on a floating platform in the Atlantic Ocean. 
 
 It sounds insane, and to be honest even Elon Musk gives it a coin toss chance of working. But the attempt will be done to test out a series of systems that will allow the eventual safe return and re-use of the first stage rocket. Once this works, Musk projects it will result in a big cost saving for future flights of the F9. 
 
 SpaceX has been testing relanding the first stage booster for some time, with a decent success rate. The floating platform has GPS sensors and the ability to hold its position under its own power even in strong currents. It sounds like science fiction, but that’s where we are today. 
 
 For details on this, I suggest reading the AmericaSpace article on the launch (and this one too), which has info galore. This is an incredibly challenging launch technically, and I hope it goes well.
– There's not much that's terribly environmentally friendly, efficient, or inexpensive about rockets—they're single-use, sometimes explode, and even when they don't they usually end up as ocean junk. SpaceX is looking to tweak that calculus with tomorrow's Falcon 9 launch in Cape Canaveral, reports the New York Times. Sure, it's sending a Dragon capsule to the International Space Station with a couple of tons of supplies. But, as Phil Plait writes on Slate's Bad Astronomy blog, "it’s what happens a few minutes after launch that has me very interested: After the initial separation, the first stage booster of the F9 will attempt a vertical landing on a floating platform in the Atlantic Ocean." In other words: Elon Musk and Co. are going to try to set a rocket booster down on a 300-foot by 170-foot barge. "It sounds insane," writes Plait, "and to be honest even Elon Musk gives it a coin toss chance of working." SpaceX has tested the feat three times, and Musk tells the Times that while they've twice soft-landed the booster in the ocean, it then "tipped over and exploded. It’s quite difficult to reuse at that point." How it ideally works: After the stage-one rocket booster separates from the Dragon, its engine will fire it around to the unmanned barge, some 200 miles east of Jacksonville, Fla. The barge has GPS sensors, and what Plait says is "the ability to hold its position under its own power even in strong currents." The Times notes that SpaceX has added "grid fins" to the rocket that fold out and help it steer. If it works, Musk has his eye on developing an entirely recyclable rocket, which he tells the Times should cuts his costs to one-hundredth of what they currently are.