[SSTO] CL-204 'Mammoth'
by Fulgora
uploaded 2016-07-26
stock spaceplane
#ssto #cargo #stock


A stock Cargo Lifter called CL-204 ‘Mammoth’. Built with 587 of the finest parts, its root part is mk3Cockpit.Shuttle.

Built in the SPH in KSP version 1.1.3.


  • Type: SPH
  • Class: spaceplane
  • Part Count: 587
  • Pure Stock

[SSTO] CL-204 ‘Mammoth’

I have put a very detailed ascent and descent description - don’t let that scare you - putting the framerates aside - this thing flies really nice and stable throughout your whole mission. There is a lot of excess deltaV so ‘mistakes’ during ascent won’t put your mission at risk - its my first SSTO and you may be able to find an even better ascent profile giving you even more deltaV in orbit (if you do let me know in the comments!)

Designed and tested in version 1.1.3


  • up to 72t+ payload
  • 100km+ Orbit
  • 1000 - 2000 dV left in Orbit depends on payload ofc
  • Docking port
  • KSP landing (is somewhat a must as it costs ~550k without fuel and cargo)
  • horrible framerates


The version displayed in the picture has an additional small cargo bay towards the front to support the full length of 2 orange tanks. The version in the download here has only one tank and comes without the small bay. I prefer to use the shorter version in regular missions at this point but adding the small cargo bay hardly changes the flight profile of the craft

Ascent profile

Make sure the payload tanks are disabled and/or the docking port has crossfeed disabled

  • Enable SAS and set thrust to 100%
  • Trigger the first stage (RAPIER + Whiplash)
  • If there is a payload of > 40t toggle nuclear engines right at the start as well (second stage or action group 4)
  • The plane will take off when it runs out of runway - you must be pitching up at this point ofc
  • Pitch to 20° in the first seconds until you are above water and keep the pitch at around 10° after that to build up speed until you are flying at ~300 m/s
  • Pitch up to 20° and continue ascent until you reach an altitude of 10km
  • Pitch down and keep your prograde(!) between 5° and 10° until you reach about 900 - 1000 m/s
  • Pitch back up to 20°
  • Make sure that your speed is around 1200 m/s at an altitude of 20k (if necessary pitch prograde back down at 18km)
  • When Rapiers start losing power (50 - 80kN) toggle closed cycle (action group 3)
  • Immediately toggle air intakes as well (action group 2)
  • Immediately toggle nuke engines (action group 4)
  • Pitch back up to 40° until apoapsis is around 70k and enable RCS (RCS is recommended but not required - there is much more RCS fuel on board than you will ever need though)
  • At 70k apoapsis shut off the rapiers (action group 3) and point prograde
  • Set up a node at the apoapsis to circularise and start the rapiers again at around T-60 seconds
  • Once the rapiers burn out finish the circularisation burn with the nukes
  • Enjoy life in orbit - you should have plenty of deltaV left to reach pretty much any orbit you desire. (except polar maybe)

Descent profile

This assumes that the payload was left in orbit…

  • Set and execute your descent node at the beginning of the desert east of KSC so that the curve hits the water a bit west of the KSC (will add a picture later)
  • Retract solar panels / heat radiators (action group 1) and toggle the (air)brakes
  • Pitch to 40° up upon entering the atmosphere
  • Once the heat indicators are gone disable the airbrakes
  • Pitch down to -30° past the mountains west of KSC
  • Adjust your pitch to you get a nice descent to the KSC itsself - this is hard to put in numbers so just go by gut feeling
  • Close to the KSC enable the air intakes again (action group 2) and the rapiers (action group 3)
  • Make sure your speed stays above 120 m/s and your prograde is around 0°
  • Slowly hit the runway - use brakes to lose speed / height right before touchdown
  • You can hit staging again right before the touchdown if you start gaining height again
  • Once you managed to touchdown without blowing up the runway (ye - thats a thing) hit staging until all two parachute-stages are deployed. This will bring you to a stop really quick given you turned off your engines ofc ;)
  • Toggle brakes as well - 200 tonnes dont stop themselves

I need in average two tries to properly land this thing and like to make a quicksave about 10km away from the KSC. I did land this several times on frist try as well but the partcount is giving me a framerate of about 10 FPS at touchdown and that makes it more challenging that it has to be. Here is hoping for better optimization in KSP v1.2 :-)

Questions / Suggestions welcome!

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