Slow SSTO

[stormdot5]

The goal of this challenge is to develop a capable reuseable SSTO spaceplane without using the turbojet engines or RAPIERs. Scoring is based around getting a better payload fraction. The flightplan to follow is to take off from the runway horizontally. Take a payload to either LKO (Low Kerbin Orbit) or KTO (Kerbisynchronous Transfer Orbit), then detach a useful payload. After that, safely de-orbit and land horizontally, as KSC if possible.

Ruley Bits

SSTO means no dropping things before reaching a stable orbit (periapsis above the atmosphere, 70km). After this you can ditch payload related items, but not core plane parts.

Spaceplane means the aircraft must be capable of horizontal take off with less than one thrust to weight ratio and horizontal landing. It can have greater than one TWR but must be able to take off with less if required.

Payload fraction is defined as mass of the payload / starting ship mass * 100 to give a percentage.

LKO is defined as 100km * 100km orbit.

KTO Is defined as Apoapsis at or above 2868.75km and periapsis above the atmosphere (70km, to prevent wild suborbital leaps). Reason to go to KTO? Double score.

Useful payload means a satellite, transfer stage, crew pod(maneuverable, not a floating coffin), etc. Whatever you can dream up, just things like plain fuel tanks need some architecture to allow them to be functional.

Screenshots for entry:

Clear view of vessel on runway

At flight events (e.g. rocket switchover)

View of orbit established (Ap/Pe visible)

View of payload (Don't need to see the payload complete it's objective but you've come this far...)

Landed, with resources tab open

Extra Fun

Bonus points don't affect score but can be achieved for extra credit;

+1 Packaged - Payload is carried in a cargo bay

+1 In safe hands - Have a kerbal pilot the flight

+1 Recycling - Recover a previous payload from orbit after first payload detachment

+1 Multipack - Multiple payloads able to be lofted to orbit in one go

+1 Explorer - Payload is equipped to travel to one of Kerbin's moons

+1 Steady climber - Plane has less than 1 TWR ratio until rocket ignition (Or Ions if you can get them to work)

+1 Electric Charge - Orbital insertion completed by Ion engines (Must deliver a reasonable proportion of orbital speed)

+1 Return to sender - Land on KSC Runway

+1 Tales from space - Entertaining story or video

+1 Rapid turnaround - Attach a new payload, refuel and go again without recovering the vessel

+1 Contingency - Crew and or Cargo have a survivable abort mode during atmospheric flight

+2 Voyager - Payload has an interplanetary departure stage

+2 Ace - Flight to and from orbit using only stock IVA instruments (Outside view allowed for on stable orbit maneuvers/payload working. Engine start to orbit and deorbit burn to touchdown completed in IVA). Video would be required for this.

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-1 Acceptable risk - loss of a kerbal during the mission

-1 Scratched the paint - Damage to the payload during mission

-2 Safety not guaranteed - Loss of the payload

-2 One way ticket - Loss of the launch vehicle after payload detachment

Mods guidelines

NEAR/FAR/DRE allowed (encouraged)

Spaceplane+ allowed

Realchute allowed for drag chutes

I may add more instructions to cover a glaring rule loophole oversight or to improve the competition in the challenge if required.

Thanks for reading, hope you have fun designing and flying.

[stormdot5]

Here's my entry for demonstation of the concept using FAR/DRE. I'm sure this is easily beatable.

The craft is Linerunner

Weighing 19.092T on the runway Including the payload, Gooey probe, coming in at 725kg

Safely delivering this to orbit sets a payload ratio of 3.79% to 2 s.f.

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The plane is realtively easy to fly, with some self stabilising tendencies. Gentle pitch up takeoff at 100m/s. SAS is used at the high angle of attack atmospheric ejection burn. Glide ratio is brilliant, can cross the runway threshold at 70m/s on approach. Maintains control to low, easy landing speeds.

Cost of plane (No payload or adapter) 32721

Value of fuel used in flight 990

Cost per ton of payload 1365.5/ton

Gooey probe is a low Munar orbit science experiment. +1 Explorer

Linerunner safely returns to KSC runway, +1 Return to sender

Total extras +2

Hope this encourages some entries.