Recently, Boeing created a website called "Watch US Fly" to promote its aerospace industry—a grab bag of everything from Chinese tariffs to President Trump's visit to the company's facilities in St. Louis. Among the most intriguing sections is one that promotes the company's Space Launch System rocket and argues that SpaceX's Falcon Heavy booster is "too small" for NASA's deep exploration program.

"The Falcon Heavy launch turned heads in February, but SpaceX's rocket is a smaller type of rocket that can't meet NASA's deep-space needs," the website states. "Once the Boeing-built SLS is operational, it will be the most powerful rocket ever built."

The Boeing site backs up this claim by quoting NASA's Bill Gerstenmaier, who talked about the differences between the SLS rocket and Falcon Heavy at a meeting of the NASA Advisory Council meeting in March. Gerstenmaier, the chief of NASA's human spaceflight program, said the SLS had "unique capabilities" that the Falcon Heavy rocket does not have. However, as Ars reported at the time, Gerstenmaier actually struggled to explain why NASA needed the SLS rocket because the space agency has not yet built anything that will take advantage of those capabilities.

The SLS promotional website also makes some questionable assertions. It speaks of the super-powerful SLS rocket as if it will soon exist. But the SLS booster is probably at least two years away from its maiden flight. Moreover, the version of the SLS rocket that flies in two years will not come close to being the "most powerful rocket ever built." That will come much later, if ever.

Most powerful rocket

The "most powerful" title belongs to the Saturn V rocket. NASA used them in the 1960s and 1970s for the Apollo program, and they had the capability to lift 118 metric tons to low Earth orbit. The initial configuration of the SLS booster will be able to lift 70 tons to low Earth orbit, which is marginally more than the Falcon Heavy and its 64 tons. (Compared to the Falcon Heavy, the SLS will have a more powerful upper stage, enabling it to send more mass into deep space).

NASA does have plans to upgrade the SLS rocket to a 105-ton configuration, but this will not occur until at least the mid-2020s and will probably cost several billion dollars as NASA contracts with Boeing to build an entirely new upper stage. Finally, the 130-metric-ton version—the "most powerful rocket ever built"—has no real timetable. Certainly, it seems unlikely to fly within the next decade.

By then, the proposed 130-metric-ton SLS may well be superseded by the Big Falcon Rocket under development by SpaceX or Blue Origin's proposed New Armstrong booster. In any case, comparing the Falcon Heavy to a rocket that won't exist for at least a decade and without many billions of dollars in public investment seems spurious. Boeing also makes no mention of the huge cost disparity between the two rockets.

There is one final interesting nugget on the Boeing website. The end of the SLS blurb invites readers to "Learn more about why the SLS is the right choice for NASA" by linking to a news story in the London Evening Standard. This is a conservative British tabloid owned by a Russian oligarch and former KGB agent, Alexander Lebedev.

The author of the Evening Standard story, an online general assignments reporter named Sean Morrison, did not listen to the NASA Advisory Council meeting where Gerstenmaier commented about the SLS' capabilities. Rather, he quoted (without linking) from another news article from the "technology news website Ars Technica."