This drawing, which appeared last year in a NASA presentation on the Congressionally mandated Space Launch System, says it all.

launch vehicle size comparison

The Space Launch System is obviously far more capable than any other launch vehicle because it’s larger, right?

We can imagine a similar drawing produced by the US Army Air Forces during World War II:

World War II transport size comparison

The DC-3 (known in military circles as the C-47 Skytrain) was a tiny airplane by modern standards, smaller than many of today’s commuter jets. At the start of World War II, it was already considered too small and outdated by the military brass. Hence, the need for an aircraft like the Hughes H-4 Hercules.

Yet, it was the C-47, not the Hercules, that did the heavy lifting all throughout the war, and General Dwight Eisenhower named the C-47 as one of the four machines that won the war in Europe.

C-47s carried VIPs and paratroopers, spare parts, ammunition, and construction equipment. They carried pierced steel plate for their own runways. They carried horses and cattle, generators and gasoline. They carried complete fighter planes with the wings removed for transport. With the aid of the C-47, the United States built a string of air bases stretching all the way across the Pacific.

The Hughes H-4 Hercules, better known as the Spruce Goose, never even made it into the air by the end of the war. So, which was the more capable aircraft?

Of course, the difference between the XCOR Lynx and Masten XA 1.0 (on the far left side of the drawing) and the Space Launch System (on the right side) is more than size alone.

The Lynx and Masten XA 1.0 aren’t even orbital vehicles. The difference in performance between a suborbital vehicle and an orbital system is enormous, like the difference between an Apple II and a Cray supercomputer. We can imagine that drawing, too. And yet, it was the Apple II and its successors that ultimately proved to be the more capable computers. Mainframe supercomputers had an enormous head start but  microcomputers ultimately won because of the power of exponential growth, which favors technologies that have short development cycles and can evolve faster.

We recently visited the Computer History Museum in Mountain View, California and saw a Cray 1 computer on display. It’s an impressive machine. It’s iconic appearance looks high tech even today, and it’s almost as powerful as the iPhone we used to take its picture.

That’s evolution in action. The suborbital vehicles of today are the space-transportation equivalent of the Apple II, laughably underpowered compared to giant mainframes like NASA’s Space Launch System, but they will drive down cost and open up space in ways we can barely imagine today.

Yes, we’ve said this before, and yes, we’re starting to sound like a broken record, but we will keep on saying it, because some things need to be said again and again, with fierce conviction.

Written by Astro1 on June 6th, 2012 , Commercial Space (General), Space Exploration (General)

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