NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

NASA/Bill Ingalls

Say what you will about the Space Launch System. It's expensive, costing so much that NASA can't really afford to build payloads to fly on it. The Senate specified the rocket to fly with components derived from the Space Shuttle expressly to preserve jobs that otherwise would have been lost following the shuttle's retirement. And the entirely expendable launcher uses 1970s technology while private companies are focusing on smaller, modern, and reusable rockets.

All of that, more or less, is true. But it is also undeniable that the Space Launch System, whenever it does fly, will be one hell of a firecracker. On Tuesday, the space agency offered a taste of that when it demonstrated the firing of one of the solid rocket boosters that will help blast the SLS rocket off of the launch pad.

These boosters will provide about 75 percent of the thrust needed to lift the rocket and its payload into low-Earth orbit. As implied by their name, the boosters burn a solid composite made largely of aluminum. During Tuesday's test, a single booster produced about 3.2 million pounds of thrust. By way of comparison, a Falcon 9 rocket with its nine engines produces about 1.7 million pounds of thrust.

Tuesday's qualification test was part of NASA's plan to continue developing the SLS rocket, consisting of two boosters and a core stage, in time for its initial test flight in late 2018. During a teleconference with reporters after the test, NASA's chief official for human spaceflight, Bill Gerstenmaier, said the flight would likely come in October or November of 2018. This uncrewed flight, Exploration Mission-1, will send the Orion spacecraft out beyond the Moon and back. "We’re in pretty good shape for EM-1 and we’re moving at the right pace," Gerstenmaier said.

With the initial version of the SLS rocket, NASA intends to have the capability to lift 70 metric tons to low-Earth orbit. An upgraded version of the rocket with a more powerful upper stage, scheduled to fly sometime in the early 2020s, will have the capability to lift 105 tons. That number compares favorably to the Falcon Heavy rocket being developed by SpaceX, with a capacity of about 54 tons to orbit. However, the Falcon Heavy will cost about one-tenth, or considerably less than that, per launch than the government-developed SLS.

Listing image by NASA/Bill Ingalls