How SpaceX and NASA’s rockets compare

How SpaceX and NASA’s rockets compare
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At a time when pivotal decisions are being made about our national priorities for spending and investment, it is imperative that our decision-makers and the public are able to distinguish fact from fiction. As Congress and the administration weigh options and strategies for critical investments in deep space exploration and low earth orbit development, the facts need to be clear.  

Unfortunately, a few recent headlines and ill-informed opinion editorials have suggested that the success of SpaceX’s Falcon Heavy test launch spells trouble for NASA — that somehow the agency’s own rocket, the powerful Space Launch System (SLS), is unnecessary. Nothing could be further from the truth. Without taking anything away from Falcon Heavy’s impressive performance, it is important to keep in mind the major key differences from SLS.


According to SpaceX, Falcon Heavy is not currently slated to carry human beings into space. That means it will not require many of the safety features that must be built into the SLS. In addition, the Orion crew vehicle that will ride atop SLS has a Launch Abort System that will be heavily tested to further reduce risks to crew while on the launch pad and during the potentially dangerous early stages of ascent.


Falcon Heavy may be perfectly acceptable for launching fairly large billion-dollar satellites or groups of smaller satellites, but it simply does not require the kind of rigorous engineering needed when human lives are at stake.

Second, there is a significant difference in power between Falcon Heavy and SLS. Simply put, the Falcon Heavy can lift around 64 metric tons and the evolved SLS can lift 130 metric tons to low Earth orbit. This difference really adds up when you are talking about going beyond low earth orbit (about 220 miles from Earth) to destinations like the Moon (around 240,000 miles from Earth) and Mars (around 34,000,000 million miles from Earth).

While SLS can launch both Orion and a 10-ton cargo element to the Moon, Falcon Heavy cannot even launch a fully-outfitted Orion to the Moon. SLS also offers unparalleled volume capability. The large fairing that will be used for SLS cargo launches can fit the equivalent volume of a 3,800-square-foot home, while the volume of the Falcon Heavy fairing is equivalent to a 750-square-foot apartment.

The crewed version of SLS that will launch Orion can carry the equivalent volume of a 1,600-square-foot home in addition to Orion. The combination of lifting power and volume means that the SLS can carry large segments or pieces of infrastructure into space with one launch, rather than having to design smaller elements that must then be assembled in space.  

As a result, the use of the SLS reduces complexity, both on the ground and in space. Reduced complexity means a reduced chance of error and difficulty with assembly — whether we’re talking about space infrastructure or a sports car. Neither the Falcon Heavy nor any other existing rocket comes close the capabilities of SLS for Deep Space missions.

Ultimately, there is a key simple truth that underscores the differences between Falcon Heavy and SLS: Falcon Heavy belongs to Elon Musk, and SLS belongs to the American people. SLS asserts the leadership position of the United States, adding to our soft power in a way that a commercial rocket never could. In addition, using SLS for deep space missions ensures future discoveries will be available to all, not held exclusively by one company. 

When the strong, bipartisan majorities in the Congress directed NASA to develop the SLS and continue the development of Orion as a multi-purpose crew vehicle, they did so in order to ensure that the United States, acting through its government, would have a national launch capability that could ensure its continued leadership in space as humanity begins the long journey to the Moon and beyond. 

That is not an undertaking that could — or should — be undertaken by wholly private entities, any more than the country should maintain a standing military by means of private companies. Indeed, the space realm constitutes an important arena wherein our national security must be maintained. Assured access to that realm must be a priority for the country, using all available capabilities, including government, private and partnership-generated capabilities. 

Today NASA enables many commercial companies, including SpaceX, to undertake innovative and exciting missions. In approximately two years, SLS will launch for the first time, opening a new era of space exploration. With SLS, we will be able to travel deeper into space than we have ever gone. When this happens, we all stand to benefit.

Jeff M. Bingham is a former senior advisor on Space and Aeronautics to the Republican staff on the Senate Committee on Commerce, Space and Transportation.