A unified theory of suborbital docking and refueling
by Francis Chastaing
|It is now possible to evenly compare suborbital refueling and suborbital docking through the same rocketplane. And the results are nothing short of astonishing.
My objective, based on my interest in the topic (see “Suborbital refueling: a path not taken”, The Space Review, February 3, 2020), was to create an Excel spreadsheet where the two could be compared, back to back. Indeed, a major difficulty is that the vehicles in the above papers are radically different: Black Horse and FLOC are like Laurel & Hardy. Imagine if instead the same identical rocketplane could be plugged into a unified docking and refueling spreadsheet. This would allow a direct comparison of suborbital docking and suborbital refueling.
But to do that, I realized that I had to be able to recalculate—re-proof—the numbers found in the two papers and validate that in Excel spreadsheet formulas. Not because I doubt Clapp and Goff, but instead more a matter of self-reliance. To me, this is akin to carving the two separate theories in granite. Well, I have managed to do this in the linked spreadsheet.
For the sake of honesty, I have included screenshots of the calculations as they appear in those papers. I recalculated Clapp’s two examples and Goff’s FLOC in individual spreadhseets. One can see that the Excel spreadsheet formulas (above) brings the exact same results as in the screenshots from their papers. As for the fourth sheet: it is the unified theory.
It is now possible to evenly compare Clapp and Goff: suborbital refueling and suborbital docking, through the same rocketplane. And the results are nothing short of astonishing.
The vehicle is called MUST: MUltipurpose Space Transport. Its concept of operations (CONOPS) would be as follows:
This is the basic CONOPS for MUST: two vehicles, one refueling. It is the ultimate development of Clapp concept. Then there is Alan Goff’s own idea: multiple dockings. It doesn’t work with two or even three vehicles. But four, six, and eight “flocks” brings astonishing payload numbers to orbit.
In the end, the alliance of Clapp and Goff concepts around the same, large, tripropellant rocketplane would truly unlock the space frontier. And with two more refuelings—Earth orbit and the Earth-Moon L-1 Lagrange point—the same rocketplane could land on the Moon. Just think about it: from the surface of the Earth to the surface of the Moon with just one vehicle and three refuelings.
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