The advent of fully reusable launch systems took another partial step forward with last Thursday’s liftoff of a SpaceX Falcon 9 carrying the U.S. Air Force’s X-37B space plane, also known as the Orbital Test Vehicle. The mission, dubbed OTV-V, was the fifth launch overall for the fleet of two unmanned spacecraft, with the first four having been carried out by United Launch Alliance’s Atlas V rocket. This time however, in something of a surprise move, the Air Force signaled an increasing confidence in SpaceX by awarding the launch to the Falcon rocket without, according to ULA, giving that company the opportunity to bid. Apparently the “Assured Access to Space” shoe feels a bit tighter when placed on the other foot.

Nevertheless, with the Air Force having declared the launch a success, one might reasonably expect that the two companies can look forward to an alternating series of future assignments to fly the unmanned space plane whose description is invariably tagged with the word “mysterious.”

The occasion of the first SpaceX launch of the X-37B however marked a noteworthy closing of the circle in a program that dates back to the late 1990’s and NASA’s now nearly forgotten Space Launch Initiative, a short-lived effort to reduce the cost of access to space in what was supposed to be the next step forward after the Shuttle program. At the heart of SLI was the Second Generation launch program, which was aimed at developing a fully reusable two-stage-to-orbit space launch system. Under NASA, the X-37 program was supposed to “test and validate technologies in the environment of space as well as test system performance of the vehicle during orbital flight, reentry and landing.”

As originally conceived the X-37 would have flown to orbit in the Space Shuttle’s cargo bay, a plan which was then modified to utilize the venerable Delta II rocket for rather understandable cost reasons. Ultimately the program was transferred to the Defense Advanced Research Projects Agency (DARPA) and then assumed by the Air Force. Concerns over the aerodynamic loads the un-encapsulated space plane might impose on the Delta II rocket finally led to the Atlas V and its larger payload shroud being selected for the first flights beginning in 2010.

Fast forward to 2017, and the fifth launch of the OTV, and a funny thing happened. A reusable space plane which was originally developed as part of an estimated $6 billion dollar project to one day develop a Second Generation reusable launch vehicle, but has now been drafted into doing James Bond kind of stuff, was lofted to orbit by a commercial rocket whose first stage promptly flew back to a safe landing as it has now done some 16 times.

The goals of the Space Launch Initiative, if not the manner or the means, are finally coming true. Except it didn’t cost the taxpayers $6 billion, a number which certainly would have ballooned well beyond that figure before anything on the scale of the Falcon 9 got built, much less launched. In fact, in terms of direct investment, it didn’t cost the taxpayers anything at all.

While NASA originally paid SpaceX $396 for its contribution to the Commercial Orbital Transportation Services (COTS) program which produced the now partially reusable Dragon capsule, very little funding actually went to the Falcon 9 booster itself, and none to the reusability campaign which is now paying off. While the Falcon 9 is not yet the fully reusable two-stage-to-orbit rocket envisioned by the Space Launch Initiative, not mention Elon Musk, as recently as this summer SpaceX has indicated it is still determined to recover the vehicle’s second stage as well.

SLI was also oddly prescient in another way as well. Contained within program language at the time was one of the earliest calls for commercial resupply of the International Space Station. And while NASA did not directly fund development of the Falcon 9, there can be no doubt that it was the agency’s awarding of a resupply contract for the Station, amounting some total 15 launches at the time, which secured the booster’s future.