PDF《Multi-Mission Radioisotope》

Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) Ryan Bechtel Space and Defense Power Systems Power System Safety Manager U.

S. Department of Energy Radioisotope Missions― Collectively 200+ Years* of Space Science ? Probes have resulted in

20 planetary encounters C All planets except Mercury C Examined numerous moons ? Five Apollo experiments collected data for combined

30 years* ? Mars landers/rovers operated for

17 years* ? Planetary orbiters for

20 plus years* ? Polar orbiting observation of the sun C Solar observations

19 years ? Five missions will reach beyond edge of solar system C Probes to deep space may operate for combined

120 to

150 years*

2 p p y p y * Cumulative operating time―some elements operating concurrently.

46 RTGs were used safely in

27 missions since

1961 10 Earth orbit missions (Transit, Nimbus, LES) ( )

8 planetary missions(Pioneer, Voyager, Galileo, Ulysses, Cassini, New Horizons)

6 on lunar surface missions (Apollo ALSEP)

3 on Mars surface missions (Viking

1 & 2, MSL Curiosity)

300 RHUs were used safely in

10 missions since

1969 6 planetary missions (Pioneer

10 & 11, Voyager

1 & 2, Galileo, Cassini)

1 on lunar surface missions (Apollo 11)

3 on Mars surface missions (Pathfinder, MER A & B) MSL Curiosity (2011) Multi-Mission Radioisotope Thermoelectric Generator

4 MMRTG Properties Components Quantity Modules

8 Fueled Clads (total)

32 ( ) Radiological Properties Quantity (Beginning of Mission) Activity Level (total) 60,000 Ci 238Pu 3,478 g Pu (total) 4,103 g Fuel Half Life 87.75 yr Power Level Quantity (Beginning of Mission) Thermal Power 1,975 W Electrical Power Output

110 W

5 Electrical Power Output

110 W Physical Parameters Quantity MMRTG Mass 43.6 kg Length/Diameter (fins) 66.8 cm/64.2 cm Operating Life A t least

14 yrs MMRTG on Mars MMRTG has successfully and reliably powered the Curiosity rover on Mars since Aug

2012 6 Key Safety Features of Radioisotope Power Systems ? Ceramic Fuel C Very Low Vaporization Rate C Generation of Respirable Generation of Respirable Fines Minimized C Highly Insoluble ? Iridium Clad C Fuel Containment C Impact Protection C Corrosion Resistant Material Compatibility

7 C Material Compatibility C High Melting Point (2400 °C) ? Graphite Impact Shell Key Safety Features of Radioisotope Power Systems C Impact Protection C Reentry Ablation Protection ? Graphite Insulator C Reentry Thermal Protection ? Graphite Aeroshell C Impact Protection

8 C Primary Reentry Ablation Protection Radioisotope Heater Units

9 ?Explosive Over Pressure Test ?Fragment Projectile Test ?Drop Test RPS Safety Testing ?Drop Test ?Solid Propellant Fire Test ?Bare Clad Impact Test ?General Purpose Heat Source Impact Test ?Large Fragment Test ?Flyer Plate Test ?RTG End-on Impact Test

10 RTG End on Impact Test ?Iridium Ductility Test ?Solid Propellant Fire Characterization test