SPEAR Probe

SPEAR (Swarm-Probe Enabling ATEG Reactor) is a compact nuclear power and propulsion system developed by Howe Industries for deep space exploration, with a primary mission goal of deploying a swarm of CubeSats to sample the water plumes of Jupiter moon Europa to test for biosignatures. The system uses an Advanced Thermoelectric Generator (ATEG) technology developed by Howe Industries to convert fission reactor heat into electricity at 20% efficiency over a 14-year operational life.

The SPEAR spacecraft total wet mass is 1,540 kg with a 70 kg payload capacity. The reactor generates 15 kW of thermal power, converted to 3 kW of electrical power for spacecraft systems and payloads. The U10-Mo fuel design enables the sustained fission operation required for a 14-year mission lifetime in the radiation-intense environment of the outer solar system, while the ATEG converter has no moving parts and degrades predictably over the mission lifetime.

The mission architecture calls for the SPEAR carrier vehicle to transit to the Jovian system over several years, then deploy a swarm of CubeSat probes that fly through the Europan water plumes. Detection of organic molecules or other biosignatures in plume samples would represent one of the most significant astrobiology discoveries in history. The estimated mission cost of 30 to 360 million places SPEAR in the NASA Discovery-class mission category, making it a potentially competitive proposal against conventional large spacecraft designs.