SSTO G-6 Proteus Mk.2
by Val
uploaded 2015-12-04
(updated 2015-12-05)
stock spaceplane
#Seaplane #SSTO #Laythe #Mk2 #RAPIER
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The G-6 Proteus is a Seaplane SSTO capable of bringing 2 t payload to Laythe. With efficient use of Gravity Assists, it might be possible to make the journey to Laythe and back to Kerbin without refuelling.

It’s equipped with Hydrofoils for fast travel across water surfaces. Use Panthers in Wet Mode to get up to 60-80 m/s. and then continue cruising in Dry mode for efficient travel.

There are 3 propulsion systems. 2 Panthers for water operations, 2 RAPIERs for leaving the atmosphere, and 1 LV-N for orbital maneuvers.

2015-12-05: Updated to be more stable with no cargo during ascent.

2016-01-12: Due to the low TWR of LV-N, interplanetary burns will require several PE kicks when starting from low Kerbin orbit. For more information see the Precomputed Low-TWR Interplanetary Transfer Burns by Red Iron Crown.

2016-02-23: SQUAD has showcased a new mod on Modding Mondays that can help making PE kicks: Maneuver Node Splitter

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  • Front external docking port
  • Full translation RCS
  • Propulsion: 2 J-404 Panther, 2 RAPIERs, 1 LV-N
  • Liquid Fuel: 4880
  • Oxidizer: 880 (Only used to leave Kerbin)
  • Dry Weight: 23.1 t.
  • Wet Weight: 51.9 t.
  • Max Payload (Laythe): 2 t.
  • Max Take-off weight: 53 t.
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  • Type: SPH
  • Class: spaceplane
  • Part Count: 96
  • Pure Stock
  • Built in the SPH
  • KSP version 1.0.5
  • Cost: 100,594
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Ascent Profile

  1. SAS on, Full throttle, Stage to activate Panthers and RAPIERs. Both should both be used for ascent. If on water, keep nose pitched 2°-3° above horizon, while building speed.
  2. At 80 m/s lift nose and take-off.
  3. Pitch up to 15° above horizon.
  4. At 5 km pitch down to 10° above horizon.
  5. At 8 km pitch down to 5° above horizon.
  6. Shut down Panthers when they flame-out at ~1000 m/s (Action Group 4)
  7. At 15 km pitch down to be level with the horizon.
  8. At 1350 m/s pitch up gently to 8° above horizon.
  9. At 18 km engage LV-N (Action Group 1)
  10. At 22 km switch RAPIER Mode. (Action Group 2)
  11. Shut down RAPIERs when they flame-out at 1900 m/s (Action Group 5)
  12. When AP is at 85 km altitude, throttle down, turn prograde and coast to space.
  13. Circularize at AP and unlock the LF in the nose.
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Descent Profile

  1. 80 km orbit. In Map mode, focus Kerbin and turn camera so KSC is facing towards you right above the Navball.
  2. Time warp until your spaceplane is right behind Kerbin.
  3. Put a maneuver node right where you orbit appears from behind Kerbin on the left side.
  4. Pull the retrograde handle until the maneuver is ~100 m/s dV.
  5. Move the maneuver node until the planned orbit intersects the surface through KSC.
  6. Pull the prograde handle until the maneuver is ~80 m/s dV.
  7. Perform the maneuver.
  8. Turn Prograde and time warp till you enter atmosphere.
  9. Keep nose ~35° above horizon until your speed is around 1500 m/s. (May need to move fuel around to keep stable)
  10. You should be nearing the coast of the landmass where KSC is at 25-30 km altitude.
  11. Nose down 5°-10° below horizon and aim to pass the mountains at 10 km, at 650-750 m/s.
  12. Nose down further, if needed, and aim for a point about half the runway length in front of the runway.
  13. At 200 m, flare and aim for the runway.
  14. Touch down with less than 3 m/s vertical speed.
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