Brian Gore wrote:I don't mean to be a downer on this momentous rollout. But can someone explain the practical use of this aircraft for such a high dollar endeavor?
The gist of it is that by using a jet to get past the majority of the atmosphere, you can make that portion of the journey(with the highest drag forces) without having to carry your own oxidizer. Expensive to build but in rocketry terms, a pretty much infinitely reusable stage or more realistically half stage.
There are alternatives, i.e. SpaceX uses superchilled RP-1 and LOX along with uprated engines to get more bang out of the same size rocket. Chilling the propellants significantly increases their density allowing the same size tanks to hold much more. Unfortunately, it isn't practical to combine the two methods as densified propellants must be loaded immediately prior to launch to achieve the maximum benefit and adding fueling equipment, chillers, etc. to the carrier aircraft would not be practical.