Tutorial:Refueling in space

Refueling in space

Specifications

==== Length: 1-3 hours====
==== Difficulty: Advanced====

Description

    You've flown for many years (most in time acceleration). Finally, after aerobraking at Jool and Laythe, you're all set to deploy the Tylo base of your dreams. Halfway through the descent, you run out of fuel, forcing Jeb to use the escape pod. Sound familiar? Yeah, I thought so. That's why this tutorial is about Refueling in Space!

    You have 2 approaches to refueling: fly up a fuel tanker or use ISRU.

Fly Up A Fuel Tanker

Step 1 - Design your fuel tanker

I recommend this design:

• Tanker
  • 1x Clamp-O-Tron Docking Port
  • 1x Rockomax Brand Adapter 02 (upside down)
  • 1x RC-L01 Remote Guidance Unit
  • 1x FL-R1 RCS Fuel Tank
  • 1x Rockomax Jumbo-64 Fuel Tank
  • 4x RV-105 RCS Thruster Block (in 4x symmetry, at the top of the FL-R1 RCS Fuel Tank)
  • 4x RV-105 RCS Thruster Block (in 4x symmetry, at the bottom of the Rockomax Jumbo-64 Fuel Tank)
  • 2x Gigantor XL Solar Array (in 2x symmetry, in the middle of the Rockomax Jumbo-64 Fuel Tank)
  • 1x MechJeb unit (AR202 case) (emergency only!)
• Transfer Stage
  • 1x Rockomax Brand Decoupler
  • 1x Advanced Reaction Wheel Module, Large
  • 1x Rockomax X200-32 Fuel Tank
  • 2x FL-T200 Fuel Tank (2x symmetry, attached radially around the bottom of the Rockomax X200-32 Fuel Tank)
  • 2x FTX-2 External Fuel Duct (2x symmetry, feeding fuel from the Rockomax X200-32 Fuel Tank to the FL-T200 Fuel Tanks)
  • Some EAS-4 Strut Connectors (to strut stuff up)
  • 4x RV-105 RCS Thruster Block (in 4x symmetry, at the top of the Advanced Reaction Wheel Module, Large)
  • 4x Stratus-V Cylindrified Monopropellant Tank (in 4x symmetry, in the middle of the Rockomax X200-32 Fuel Tank)
  • 4x RV-105 RCS Thruster Block (in 4x symmetry, at the bottom of the Rockomax X200-32 Fuel Tank)
  • 2x RV-105 RCS Thruster Block (in 2x symmetry, in the middle of the FL-T200 Fuel Tanks)
  • 2x LV-N "Nerv" Atomic Rocket Motor (in 2x symmetry, at the bottom of the [FL-T200 Fuel Tank]]s)
• Launch Vehicle
  • 1x Rockomax Brand Decoupler
  • 1x Rockomax X200-16 Fuel Tank
  • 4x RV-105 RCS Thruster Block (in 4x symmetry, at the top of the Rockomax X200-16 Fuel Tank)
  • 4x Stratus-V Cylindrified Monopropellant Tank (in 4x symmetry, in the middle of the Rockomax X200-16 Fuel Tank
  • 4x RV-105 RCS Thruster Block (in 4x symmetry, at the bottom of the Rockomax X200-16 Fuel Tank)
  • 1x Rockomax "Skipper" Liquid Engine
  • 1x Rockomax Brand Decoupler
  • 1x AE-FF2 Airstream Protective Shell (2.5m) or Procedural Fairings fairing or KW Rocketry fairing
• Launch Vehicle of your own design (that can get into orbit)

Step 2 - Launch your fuel tanker

Use a normal ascent profile to get into a circular orbit with a periapsis greater than 75 km and deploy your Gigantor XL Solar Arrays. Now you should be on the upper stage (the one right before the transfer stage). Fire your engines to get a transfer to whatever planet/moon your target is orbiting.

Step 3 - Rendezvous and Docking

Using the transfer stage, rendezvous with the target spacecraft. Once you are within 250 meters, cancel your relative velocity and jettison the transfer stage. From there, dock with your target.

Step 4 - Transfer Fuel

Right-click on the Rockomax Jumbo-64 Fuel Tank of your fuel tanker. If you've followed the tutorial, it should be full. Then, hold Alt (Option on a Mac) and right-click on the fuel tank of your target spacecraft that you want to refuel. The right-click menu should have a section labeled "Transfer." Under that section, press the buttons labeled "In" on both the Liquid Fuel and Oxidizer subsections. After it's refueled, close the right-click menu and undock the fuel tanker.