Soyuz with 32 thrust chambers
Saturn 1 with eight thrust chambers
For the stage hold down firing of Falcon 9, we will be using our very large test stand (BFTS) to deal with the roughly 350 metric tons of vertical thrust generated by the nine Merlin 1B engines. We are designing the thrust frame to be able to run to tanks dry with margin, so about 340 tons of net vertical thrust has to be held down. This is no problem for the stand itself, which was designed to handle 1500 tons of thrust! It is quite epic in stature, being about 100 ft tall with ten ft diameter steel reinforced solid concrete legs that extend 70 ft underground.
The elevator is now installed along the one leg and we have the propellant supply tanks in place. Electrical power is in place and fiber communications to the blockhouse will be installed shortly. The next segment of work is digging out the flame diverter at the base, pouring the high temperature concrete and adding the water deluge system. We are hoping to have it ready for a Q2 2006 hold down firing of the F9 flight stage.
Elevator now installed on BFTS
Structures
One of the most striking differences between Falcon 1 and Falcon 9 is that, due to the size, almost everything needs a holding fixture and a crane to be moved. Even getting in and out of the tank requires a special drawbridge structure when the manway is at the center of a 12 ft (3.6 m) diameter dome! In contrast, with Falcon 1 at 5.5 ft (1.7 m), two people can easily carry around a dome or barrel section, getting in and out of the tank requires no tooling and transportation of the whole stage is easy, as it fits inside a standard semi trailer.
At this point, we have most of the machinery and tooling built for Falcon 9. All of the domes for the first tank are in house and we are welding up the barrel sections. One significant remaining tool, due to be done soon, is the circumferential stir welding fixture. Once that is complete, Falcon 5/9 will be the only launch vehicle in the world that has fully stir welded tanks. The layup and trim tools for the composite thrust skirt and interstage are done and we are putting together our first 12 ft diameter composite barrel section.
"It is astounding to me that so many rockets out there use completely different stage structures for the 1st and 2nd stages. It is a huge cost savings to be able to build the 2nd stage as simply a short version of the 1st stage. All that changes is stringer density and skin."
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