NASA’s Space Launch System is America’s ride to the moon and beyond

As a veteran of four flights on NASA’s space shuttle, I can tell you that human spaceflight is a hard, complex endeavor. And when astronauts’ lives are at stake you must get it right the first time. That’s why I was impressed with NASA’s successful test firing of its Space Launch System (SLS) core stage on March 18. 

This rocket paves the way for an exciting era of U.S.-led space exploration, leading to a permanent human presence on the moon and eventual journeys to Mars and beyond.

The 499.6 second, full-throttle engine run, which put the core stage through a simulated launch profile, gives America a rocket specifically designed to take astronauts to the moon. That’s an indispensable capability that’s been missing from NASA’s exploration toolbox since Apollo’s Saturn V made its final flight nearly five decades ago.

This test was part of NASA’s deliberate and methodical approach to developing a mammoth rocket for the SLS that should be ready to launch into deep space later this year. If that unpiloted mission goes well, the SLS should carry astronauts around the moon in 2023. 

Critics of the powerful SLS point to the interrupted core stage hot-fire test back on Jan. 16 and other program delays as evidence that NASA’s Artemis lunar exploration program should now switch to alternative commercial rockets, nearly all of which are still in development and none with the lifting power of the SLS. 

Though January’s truncated “Green Run” was a relatively small hiccup — part of the normal testing process — it seems to have reenergized those who claim commercial rockets can get America to the moon faster, sooner and at less cost than the NASA-designed SLS. One such vehicle often proposed as a substitute, in part because it is comparably sized, is SpaceX’s developmental Super Heavy, whose Starship second stage is undergoing atmospheric flight-testing at the company’s facility in Boca Chica, Texas.

Although the commercial rocket industry has made impressive progress over the last few years, the Starship and its Super Heavy booster are many years and many tests away from reliable flight and are not a realistic substitute for SLS.  

With the success of this latest hot fire test, the SLS’s 212-foot-tall core stage now heads for NASA’s Kennedy Space Center for mating with its boosters and the human-rated Orion spacecraft. On its inaugural flight, SLS will hurl the unpiloted Orion to lunar orbit and back. The last time America sent an astronaut-rated craft there was 1972. 

The SLS is real, with hardware built or on order for its first 10 launches supporting NASA’s Artemis program. Five Orion spacecraft are either in hand or have been ordered to carry astronauts, with contracting mechanisms set up for an additional nine vehicles. America should not trade all this hardware and momentum for the ephemeral lure of some cheaper alternative which may never materialize. 

In fact, SLS is the only rocket that can launch the deep space Orion crew vehicle; it has nearly three times the lift capability of any other launch vehicle in the world, either flying or in development. Adapting proven rocket technology, the SLS will enable our safe return to the moon and deep space.  

Other rockets that may reach the pad sometime this decade will have far less lifting power and thus require new orbital refueling technologies and multiple launches, dockings and maneuvers — just to get to the moon. Should we be reinventing how to get there just for the promise of future, limited-lift launchers? Or should we see through the nearly flight-worthy SLS, which delivers the reliability and brawn needed to establish America on the moon and advance to Mars? 

SLS and Orion are nearing the launch pad, Orion for its second test flight. These systems can take our nation further into space than ever before. And they can do this well before China’s promised Long March 9 heavy lift rocket debuts around 2030. Flying SLS will boost us well along toward technological leadership in the 21st century. 

Let’s put arguments about the best rocket to build behind us and fly the one we have — SLS — based on the proven shuttle engines and boosters, which I rode to the space station. If we stay the course, we will soon see Americans and our partners back on the moon, learning to live on another world and charting a course toward human exploration of Mars. 

Tom Jones, PhD is a scientist, pilot, author and veteran NASA astronaut.