Description

This medium-sized SSTO Tanker Refuelling Spacecraft is equipped with medium Clamp-O-Tron docking port and can be used to refuel a spacecraft or station. You also can use it to reduce launch costs by launching your own spacecraft with empty fuel tanks (so it weights less and requires a smaller & cheaper rocket) and refuelling it on low Kerbin orbit.

With it's 220 tons of liftoff weight, this craft can deliver up to 60 tons (12 000 of liquid fuel) to low Kerbing orbit and return back to KSC runway. After landing it can be recovered for 100% cost - limiting expences to fuel costs only.

Specifications

Loaded weight - 221 tons

Dry weight - 80 tons

Payload - 60 tons (12k of liquid fuel)

Spacecraft costs (filled) - 284k

Launch costs - 27k

Controls

1 - toggle space/atm mode (cargo bay, solar panels etc.)

2 - Nerv engine on/off

3 - Rapier engines on/off

5 - Rapier toggle mode (Atm/vac)

7 - Runway braking (engines off, brakes, braking chutes)

9 - Vertical landing gear

G - Horizontal (runway) landing gear

Brake - Airbrakes

Abort - Panic button: shuts off engines, drops fuel tanks (if any) and releases all chutes

How to fly

1. Get into orbit

a) Set ascent angle 20 deg (Heading 90, Pitch 20, Roll 0) and fire Rapier engines
b) Rapier engines in airbreathing mode will rise your apoapsis to about 35 km
c) After switching to rocket mode they will take you as high as 80 km apoapsis
d) As soon as your droptanks well become empty - drop them (stage)
e) After you run out of rocket fuel - enable Nerv engine and use it to circularise
f) Open solar panels and docking port by pressing 1

2. Refuelling your spacecraft

a) Rendezvouz with your spacecraft

b) Dock

c) Transfer liquid fuel to your spacecraft

(don't forget to leave about 1500 fuel for deorbit and landing)

3. Deorbit

a) Rebalance fuel on the craft to the fore (or your craft will be uncontrollable in flight)
b) Close all panels (1), vertical landing gear (9), ladders, docking ports etc.
c) Create a maneuver node for reentry. I usually create a 300 m/s2 retrograde burn
d) Adjust position of your maneuvering point - your final trajectory should point directly to KSC
e) Perform retrograde burn
f) Reentry:
-Set Heading 90, Pitch 0, Roll 0
-Disable Nerv (2)
-Enable Rapier engines (3)
-Switch Rapier engines to airbreathing mode
-Do not use airbrakes during reentry
g) if you've done everything right you'll be out of hyperspeed and in stable flight just ~50 km before KSC

4. Land at KSC runway (this is a tricky part)

a) If you want to use autopilot - use old "Spaceplane Guidance" from MechJeb 2.6.
It is still working for now (my current game version is 2.4.2), newer MechJeb (2.7) versions at this point seem to be useless.
b) Mechjeb only controls the heading of your craft, keeping it on the glide path. You need to adjust throttle manually
c) Keep your craft in steady flight (90-0-0) until speed falls to less than 500 m/s, then enable the MechJeb spaceplane guidance
d) Do not let speed of your craft to fall below 200 m/s as the craft may stall and become uncontrollable, adjust throttle to do that.
e) After descent to less than 1 km altitude, with about 10 km from runway begin to slow down below 200 m/s. You can use throttle and/or brakes to do that.
f) you final landing speed should be 70 +-10 m/s. If it will be higher the craft may crash,
if it will be lower - it will stall and also crash. Open te landing gear and prepare for landing.
g) When you hit the runway immediately press 7. This will:
-Shut the engines
-Release drogue chutes
-Enable both gear brakes and airbrakes
h) If everything goes well - you'll soon stop on the runway

4a. Alternative landing

If you don't want to perform a risky runway landing (or if something suddenly goes wrong and your craft becomes uncontrollable) you can always use alternative landing method.

a) To do that just press the panic button (Abort). This will:
-shut your engines
-Release normal and drogue chutes
b) Open vertical landing gear (9)

Enjoy!

SSTO (Single Stage To Orbit) "Tanker" Refuelling Spacecraft (Stock)