LOXLEO, Part III

Speculation alert:  The first two posts

1. Power requirements in space
2. NASA is moving towards the Space Launch System

I wanted to revisit this, in order to explore the proposition I put forth, particularly with respect to putting a tandem system.  The lower satellite will collect the oxygen and the higher satellite will furnish power to it.  How to execute this?

I took a look around the web in order to see if such might be feasible.  You can lower and raise the orbit in space by the following procedure:

Future Spacecraft Propulsion Systems: Enabling Technologies for Space

A tandem system could follow this procedure in order to lower the collector module down to a lower orbit, while the upper satellite could stay above it and power the lower satellite system with a power beam.  The upper satellite may get its own power from yet another orbiting satellite at GSO, or even system of satellites  at GSO so as to keep it continually supplied with energy.  The power would come from solar panels, most likely installed on a satellite orbiting at GSO.

The upper satellite at LEO could also be a fuel depot and accept the contents of the lower satellite after it finishes filling up.  It would transfer its cargo to the upper satellite after rendezvous, and then return to lower orbit for more.  The process could be repeated many times.

The advantage is from reusability of not only the modules themselves, but of other spacecraft that it can refuel.

While there is no method of getting hydrogen this way, a separate system could lift it from the ground.  Since hydrogen is the lightest element in the periodic table, the mass penalty should be the least.  If you don't have to lift LOX, you save 7/8 ths of the mass needed for a LH/LOX propellant system.

Let say you could use a Stratolaunch system to deliver the hydrogen and a LOXLEO system for the hydrogen.  Even though the Stratolaunch would be limited in how much it could bring up at any one time, it could take advantage of the LOXLEO system in order to stretch the capabilities of the hydrogen thus delivered.  Thus, each system could complement each other for maximum efficiency by using the strengths of each system.