Hydra Sandhawk Rocket Kit This water-launched sounding rocket combined a NOTS 401A booster with a Sandhawk sustainer for two-stage flights. Prior to launch, the Hydra Sandhawk was submerged in ocean water, in a floating launcher, off the California coast. The sounding rocket soared to an altitude of 175 miles, carrying its scientific payload to the very edge of space. The kit includes four plywood centering rings, and other parts to build both booster and sustainer stages. Build your own rocket kit today and relive aerospace history on a smaller scale. This rocket kit requires a launch rod (not included) and is not to be submerged in water. $28.95  Dimensions Overall length : 29.5" Diameter : 1.637" (BT60) Forward Fin Span : 5.637" Weight : 5.3oz Recommended Motors Booster : Estes® D12-0 Sustainer : Estes® B6-6, C6-5 Challenges Multi-stage rockets have two stages to build. Each stage has it's own set of fins (which are pre-cut). The Hydra Sandhawk kit includes card-stock fin mounting attachments to add more detail. There's also a payload bay which is created by cutting a slit along a body tube.