NASA Administrator Charles Bolden raised some eyebrows recently when a question was put to him at a public meeting, why is NASA spending a lot of money developing the heavy lift Space Launch System when SpaceX is also developing heavy lift at far less cost? A great answer involving the capabilities of the Falcon Heavy vs. the SLS exists. Bolden declined to issue this reply, offering instead that the SpaceX Falcon 9 uses "old technology." The assertion is false on a number of levels.

First, the Falcon 9 is not a heavy lift launcher. The rocket is the workhorse launch vehicle SpaceX is using to place into orbit everything from satellites to the Dragon cargo ship. In a couple of years, the Falcon 9 will launch the crewed Dragon to take astronauts to and from the International Space Station.

Second, the Space Launch System uses "old technology," derived from the space shuttle, though with some parts manufactured with modern 3D printing. The Falcon 9 and the Falcon Heavy uses modern engines and other up to date technology. More importantly, SpaceX is testing the first stage of the Falcon 9 to enable it to land so that it can be refurbished and reused. The company has managed to land one first stage on land and another on a drone barge at sea. If SpaceX succeeds in performing these operations routinely, it will have changed the economics of space travel.

The main advantage of the Space Launch System over existing commercial rockets is the amount of mass it can throw into low Earth orbit. The Falcon Heavy, when it enters service, will be able to lift 53 metric tons to low Earth orbit. The Space Launch System, in its final form, will be able to lift 130 metric tons to orbit, about two and a half times the Falcon Heavy. The better capacity of the SLS is a consideration for keeping human space exploration simple and less risky. The use of a commercial rocket like the Falcon Heavy would take many more launches than the SLS to send spacecraft to the moon, Mars, and other deep space destinations. The planetary science community is eager to use the Space Launch System to send large probes to the outer planets and their moons.