Point Design for 2 5 Megawatt VASIMR Engine

Point Design for 2. 5 Megawatt VASIMR Engine For Mission to Callisto in 2045 Developed with input from ASPL Team and collaborators at Oak Ridge National Laboratory, Los Alamos National Laboratory, NASA Goddard Space Flight Center, University of Texas, University of Houston, Rice University, and MIT Provided to RASC Team, NASA Langley Research Center October 2002 NASA Johnson Space Center, Advanced Space Propulsion Laboratory

Point Design for 2. 5 Megawatt Engine Magnet power supply Magnet cryocoolers (3 plus 1 spare) (Power Required: 375 W) 3 High-temperature superconducting magnets (60 -70 K) Propellant control 177 – 296 mg/sec • Deuterium 45 cm System Controller Helicon 50 MHz RF Source (750 -1250 k. W) Power Processing Unit 30 cm Exhaust 180 cm ICRF 1. 5 MHz RF Booster (1250 -1750 k. W) RF Power Distribution 2. 5 MW DC Power 15 k. V Oct 21 2002 63 cm NASA Johnson Space Center, Advanced Space Propulsion Laboratory Radiators 1351 k. W @ 500 C 75 m 2

Magnetic Field for 2. 5 Megawatt Engine Magnet Coils and Resulting Field Lines Magnet inner diameter: 76 cm Magnetic Field Profile Field Strength (T) Helicon Axial length (m) NASA Johnson Space Center, Advanced Space Propulsion Laboratory ICRF

Magnetic Coils for 2. 5 Megawatt Engine Outer shield and insulation Thermal shield (actively cooled) Magnet coil (actively cooled) 6 x 6 cm 3. 2 x 3. 2 cm 4. 4 x 4. 4 cm 76 cm 80 cm Magnet Mass : 117 kg for three coils 130 cm 165 cm Basis: BSCCO- 2223 (Bismuth-Strontium-Calcium-Copper Oxide) superconducting material Critical temperature for BSCCO-2223 is 106 K with usable current density below 80 K. Ideal operating temperature with existing magnet is 40 K. In this design an operating temperature of 60 -70 K is assumed based on modest technology advancement. NASA Johnson Space Center, Advanced Space Propulsion Laboratory

Magnet Cooling Assuming 60 -70 K superconductor Conduction & radiation load for three magnets: 3 -7 W, Heat load for leads: 5 -7 W Total Heat Load: 14 W Three coolers plus spare: 5 W capacity each at 60 -70 K Similar to TRW cooler used for Terra and Aqua EOS spacecraft (TRL = 9) Total input power: 375 W Radiating 375 W at 55 C yields 0. 63 sq. meter radiator area Mass: Total: 80 kg 4 cold heads: 4 x 10 kg = 40 kg 4 electronics units: 4 x 6 kg = 24 kg Structural support: 64 kg x. 15 = 10 kg Radiator (0. 51 m 2): 2. 7 kg Heat Pipe: 3 kg Dimensions: Cold head: 15 cm diameter, 35 cm length (4) Electronics: 20 x 10 cm (4) Radiator: 140 cm x 45 cm (top of enclosure) Cryocooler enclosure: 150 x 45 x 30 cm NASA Johnson Space Center, Advanced Space Propulsion Laboratory Cold head Based on information provided by: Rob Boyle and Shuvo Mustafi NASA Goddard Space Flight Center

Point Design for One Megawatt Engine, PPU and Cryocoolers Magnet Power Supply Magnet Cryocoolers RF Electronics (PPU) Diameter: 125 cm Outer diameter: 80 cm 200 cm Diameter: 63 cm 180 cm NASA Johnson Space Center, Advanced Space Propulsion Laboratory

Cluster of Four 2. 5 MW VASIMR Engines Looking forward Heat rejection requirement for each engine and PPU: 1350 k. W Radiator area required: 75 m 2 @ 500 C Looking aft Overall radiator diameter for cluster ~ 15 meters One double-sided panel along engine and PPU: 380 cm x 580 cm NASA Johnson Space Center, Advanced Space Propulsion Laboratory One quarter-disk-shaped panel around engine exhaust: 640 cm radius

Mass Estimate Radiator Panel Mass: One-sided: 4. 9 kg/m 2 Two-sided: 8. 9 kg/m 2 Antenna sizing based on 10 MW/m 2 Mass Estimate for 2. 5 MW Point Design 600 kg a = 0. 24 kg/k. We PPU: 1300 kg a = 0. 52 kg/k. We Total System: 1900 kg a = 0. 76 kg/k. We Engine: NASA Johnson Space Center, Advanced Space Propulsion Laboratory

Performance NASA Johnson Space Center, Advanced Space Propulsion Laboratory