Hello, I'd like to share with you all my proposal for a highly economical system to deliver crews and payloads to multiple destinations around the kerbol system. The system will comprise of several orbital tugs in space, modified second stages of my Raptor Heavy launch vehicle, which can deliver a second stage into space with just a first stage and a booster. These several different tugs are launched into space with docking ports, a mixture of solar panels and rtgs, and more monoprop tanks. Then, several Raptor Heavy launch vehicles are launched into different orbital inclinations around kerbin. Then, a Raptor 1 launch vehicle, a Raptor Heavy without four small liquid fuel boosters and a smaller fairing, could launch up payloads with a modified reusable second stage, which would deliver a payload or crew to the orbital tug via docking ports, then, it would re-enter the atmosphere, parachute down to the surface, and be recovered. To expand the effective range of said orbital tugs, more refuel depots could be delivered to the orbits of different planets and moons, to serve as stops to refuel for stages departing from kerbin. To keep prices down, this system would need to be sustained by several IRSU sites spread around the kerbol system would need to be operated, periodically replenishing their supply depots. The orbital tugs themselves have 5.1k deltav, which would allow them to deliver a payload to just about anywhere, refuel along the way if needed, refuel for a return trip, and return back to kerbin. Additionally, tugs could be kept on standby outside of kerbin around other celestial bodies, allowing economical crew and payload transport to and from any destination around the kerbol system. For instance, a mission profile could follow a tug refueling in orbit, a delivery stage delivering a payload to a tug, the delivery stage being recovered on kerbin, the tug going to, for instance, duna, delivering the payload, refueling, returning back, topping off its fuel, and repeating the cycle.
I'm going to be attempting to refine and replicate this system over time on my savegame, and trying to figure out exactly how much it could save. Thanks for reading over this, please comment with your feedback.