The Duna Experimental Utility Craft for Exploration and Science (DEUCES) is an effort to design upper stages capable of reuse once in space. Inspired by Kerbal Space Academy and ULA's ACES upper stage, these autonomous stages are capable of placing a payload somewhere, and returning to a station for refuelling for another mission. To this end, we have established several DEUCES Reference Missions (DRM), allowing missions to be scoped more quickly and with higher reliability.
DRM #1: 1250m/s
  • Suborbital to LKO (low Kerbin orbit)
  • LKO to/from Mun or Minmus orbit
  • Mun orbit, landing, and return to orbit
  • LKO to Duna/Eve transfer (no reuse)
  • Land on Moho

DRM #2: 2000m/s, 700m/s return
  • ​Suborbital to KTO (kerbal synchronous orbit), deploying a payload, and returning the stage to LKO

DRM #3: 2500m/s
  • Suborbital to Mun or Minmus orbit
DRM #4: 2500m/s, 1250m/s return
  • Suborbital to Duna/Eve transfer, returning to LKO

​DRM #5: 700m/s, 700m/s return
  • LKO to KTO, returning to LKO after deployment.

DRM #6: 1250m/s, 1250m/s return
  • LKO to Duna/Eve transfer, returning to LKO

DRM #7: 2000m/s
  • LKO to Moho/Jool transfer (no reuse)

DRM #8: 2000m/s, 2000m/s return
  • LKO to Mojo/Jool transfer, returning to LKO

DEUCES mk 0

Engines: 2xO-10

The O-10 allows the mk 0 to use monopropellant for both its main engines and RCS control. It is powered by solar panels.

Maximum Payloads:
​DRM #1: 1.7T
DRM #5: 3.2T

DEUCES mk I

Engine: LV-909
Landing Engines: 4xLV-1R

The mk I features several VR-N1ER engines and a fuel cell allowing it to use LF+OX for its main engine, RCS control, and power. Landing legs and additional engines allow for surface missions.
​
​Maximum Payloads:
DRM #1: 6.5T
DRM #2: 1.3T
​DRM #3: 1.2T
DRM #5: 12T
DRM #6: 3.1T
DRM #7: 2.5T​

DEUCES mk II

Engine: RE-L10
Landing Engines: 4x24-77

The mk II also features several VR-N1ER engines and a fuel cell​, allowing it to use LF+OX for its main engine, RCS control, and power. Landing gear and additional engines allow for surface missions.
​
Maximum Payloads:
DRM #1: 29T
DRM #2: 10T
DRM #3: 8.5T
DRM #4: 3.3T
DRM #5: 56T
DRM #6: 20T
DRM #7: 13T
DRM #8: ​2.8T