2.3 SP-100 Technology (Near Term)
• Practical Range ? 30 - 100 kWe, thermal power output of about 300 to 1000 kW to meet ice penetration time scale requirements.
• ECA (Energy Conversion Assembly) Options:
- Brayton / Vapor Compression Cycle (? ? 0.4 - 0.5) but massive
and involves turbopumps / working fluid / moving parts
- Thermoelectric (thermocouple principle) (? ? 0.05 - 0.1) low mass
but inefficient and low temperature limits (Tmax ? 1000 K)
- Thermionic (e- emission), (? ? 0.08 - 0.12) low mass, still low efficiency, but high T (Tmax ? 2000 K) means compact, smaller radiator + simplicity and no moving parts (highly reliable)