Is the Promised Land for Prompt Global Strike the Scramjet?

Posted: May 20, 2010 in Air Force, Air Force, Falcon, NASA, Pratt & Whitney, Prompt Global Strike, Scramjet, Space Launch, SpaceX, X-51

Maybe. The link is pretty much a super-long Pratt & Whitney press release touting the scramjet concept.

While all the science is cosmic, the military, as with the NBA draft, often rewards potential versus proven performance.

So can something like the air-dropped, solid rocket motor (initially) and scramjet (subsequently) powered, expendable X-51 really go from Vandenberg AFB, CA to the bogey’s cave in 60 minutes or less?

Maybe.  Someday.  Maybe someday…

While the X-51 is a 26 foot, 2000 pound vehicle, it carries no payload (besides some instrumentation, I’m sure) and is only set up for a flight profile that involves 300 seconds (that sounds more impressive than five minutes, doesn’t it?) of scramjet powered flight.

As the Air Force Association reports “AFRL believes that a scramjet 10 times the size of the X-51A’s engine is necessary to power a long-range strike missile carrying a significant weapon payload.”  An engine ten times as powerful implies ten times as much fuel…now we’re talking something quite large. Traditionally, large equals expensive.

Ok, how about scramjet as a space launch vehicle?

As Spaceflight Now reports, NASA has contemplated an unmanned 130,000 lb. scramjet-powered, winged, reusable spaceplane that could carry 300 lb. payloads into orbit.  I guess if we have 300 pound payloads, maybe we’re in business, but as of today, a 300 pound payload is pretty much some sort of typographical error

By the way, 130,000 pounds is about the weight of two Minuteman IIIs, of which we may soon have spares and could easily handle a 300-pound payload.  Or we could also consider the Falcon family of vehicles from SpaceX for those 300-pound payloads.  In fact, SpaceX’s Falcon 1e can do way better than that: it can put a 2200 pound payload into LEO and do it for less than $11 million.

In fact, while we’re at it, why don’t we consider SpaceX vehicles as prompt global strike vehicles?  A handful can be based out of Vandenberg and Cape Canaveral.  They’re cheap and capable and available almost immediately.  If we don’t use them as PGS vehicles, we can turn around and use them as space launch vehicles.  Did I miss anything?

The big advantage of a scramjet enabled vehicle as a prompt global strike weapon–assuming it is technically viable and at a reasonable (pick your own definition) cost is its political correctness: it isn’t a conventional ICBM.


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