The SS2S team completed an initial feasibility study and is currently in the design phase. They are also actively building a 1/4-scale motor. Due to technical and regulatory concerns, they could not go with a multi-stage rocket, so they will use a 2-phase segmented motor. In this type motor, the lower part of the propellant burns (phase 1), there is a coast period while a delay grain burns, and then the top portion of the motor ignites (phase 2).
Here is a summary of the preliminary vehicle specs:
- Number of stages: 1 (dual-phase operation)
- Vehicle size: 10" (25.5 cm) diameter by 26' (7.9 m) overall length
- Liftoff mass 1100 lbs (495 kg).
- Allotted payload mass 15 lbs (6.8 kg).
- Full vehicle recovery
- Propellant type, cast Potassium Nitrate/Sorbitol (KNSB)
- Propellant mass 885 lbs (402 kg), consisting of 6 BATES segments per phase (12 total)
- Burn time 8.5 seconds each phase (17 sec. total)
- Motor average thrust, 6665 lbf (29.6 kN)
- Coast time between firings, 16 seconds