Radioisotope Power Systems Enabling Space Exploration

Mission ● Present ● Past ● Future ● Capabilities

March 20, 2019

Kelly L. Lively RPS Department Manager

RPS Programmatic Mission

Fuel, test and deliver radioisotope power systems (RPS) and related technologies for use in remote, harsh environments, such as space

Radioisotope Thermoelectric Generators (RTG)

Electrical generator that converts heat generated from the

radioactive decay of Plutonium Oxide into electrical energy using

thermoelectric devices

Mission

Seebeck Effect

The heat is converted into electricity by the

Seebeck Effect using an array of thermoelectrics

A current loop and magnetic field are created

when two metals are joined in two places

(junctions) with a temperature difference

The voltage created by this effect is on the order

of several microvolts per kelvin difference

Typical hot side in GPHS Pu-238 fueled

convertors is 1273K (~1800°F) with a cold side

of 573K (~570°F).

Key Features of Space Radioisotope Power Systems

General Purpose Heat Source Module

Pluto New Horizons Mars Science Laboratory-Curiosity

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INL Accomplishments for Space Missions—Vital Statistics

MSL-Curiosity

MSL (1) Mars Rover

• MSL (1)

• BOM Power (2011) 113 We

• Efficiency ~ 6.2%

• Modules 8

• Thermoelectrics PbTe TAGS

• Mass 97 lbs

• Length 2 ft

• Fin tip-to-tip diameter 2 ft

• Launched Nov 26, 2011

• Landed Aug 5, 2012

Pluto-New Horizons

Pluto New Horizons (1) Pluto & Kuiper Belt

• BOM Power (2006) 250 We

• Modules 18

• Thermoelectrics SiGe Unicouples

• Mass 127 lbs

• Length 4 ft

• Fin tip-to-tip diameter 1.5 ft

• Launched Jan 19, 2006

• Flyby Jul 14, 2015

Pluto New Horizons

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RPS

New Horizons takes a picture

of Pluto (in Natural Color)

New Horizons is an interplanetary

space probe launched as part of

NASA’s New Frontiers Program.

Its mission: conduct a 6-month-

long reconnaissance flyby study of

Pluto and its moons.

Where is Pluto New Horizons?

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RPS

New Horizons takes a picture

of Ultima Thule (in Natural Color)

New Horizons Accomplished its

Prime Mission:

Flyby of Pluto & its 5 moons (Charon,

Nix, Hydra, Kerberos & Styx)

New Horizons Continues:

Hubble Space Telescope used to

search for post-Pluto, Kuiper Belt

flyby target designated 2014 U69 (~4

billion miles away)—Ultima Thule

(which means “beyond the known

world”). Flyby 1/1/19.

New Horizons continues to fly toward

a a barrier at the edge of the solar

system, ultimately reaching

interstellar space around 2040.

Mars Science Laboratory-Curiosity

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Curiosity is a car-sized,

six-wheeled robot investigating

Gale Crater on Mars

Mission: Could Mars ever have

supported small life forms called

microbes...and could humans

survive there someday?

Discovered organic molecules in

ancient Martian rocks & seasonal

variations of methane

concentrations in the Martian

atmosphere.

Both discoveries consistent with the

potential for existence of past or

present life—scientific interest to

keep searching...

Traveled 12.5 miles (3/2019)

Curiosity Landing Site in Gale Crater

Where is Mars Science Laboratory-Curiosity?

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2/10/19. Image taken by

NASA’s Curiosity rover

using its Mastcam

Image taken by NASA’s Curiosity rover using its Front

Hazcam on 2/13/19

February 2019 2/15/19. Curiosity gives mission

controllers a scare—entering safe mode.

2/28/19. Rover back on line—continues to investigate a region of Mount Sharp, rich in clay minerals (which form in water).

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Capabilities--Facilities

Idaho National Laboratory, Materials & Fuels Complex

Engineering Development Laboratory (EDL)

Space & Security Power Systems Facility (SSPSF)

Radioisotope Systems Training & Storage Facility (RSTSF)

Radioisotope Thermoelectric Generator Transportation System (RTGTS)

Kennedy Space Center

Radioisotope Thermoelectric Generator Facility

Payload Hazardous Storage Facility

Cape Canaveral Air Force Station

Vertical Integration Facility

Capabilities--Process

238PuO2 Fuel Clad Receipt

Generator Receipt and Inspection

General Purpose Heat Source Assembly

RPS Assembly

RPS Acceptance Testing

RPS Maintenance and Storage

RPS Cask Packaging

RPS Delivery to NASA

RPS Ground Operations

RPS Spacecraft Integration

INL Materials and Fuels Complex

SSPSF

EDL

Space and Security Power Systems Facility (SSPSF)

Radioisotope Thermoelectric Generator

Transportation System (RTGTS)

Engineering Development Laboratory (EDL)

Fuel Receipt--SSPSF Fueled clads arrive in 9516 Type B cask

from Los Alamos National Laboratory (up

to 500 Wthermal per cask)

Welded containment vessel and inner

liners and product cans are opened

mechanically

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Capabilities—Process

Module Assembly—SSPSF

The graphitic packaging provides structural and thermal protection—”thermal circuit”

GPHS modules assembled in the Module Assembly Glovebox

Fueled clads and completed modules stored in specialized containers until ready for use in RTG assembly

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Capabilities—Process

ETG Receipt

ETG inspected and removed

from shipping container

ETG placed on T-cart

Post-shipment electrical tests

conducted

Thermocouples installed

ETG moved to temporary

storage until assembly

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Capabilities—Process

Insertion into IAAC

Inert Atmosphere Assembly

Chamber (IAAC) cleaned and

tooling inserted

ETG inserted into IAAC

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Capabilities—Process

RTG Assembly

ETG heater removed

Portable Monitoring Package

(PMP) hooked-up

Tooling insertion completed

Inert atmosphere established

Mounting-end MinK insulation

disk inserted

Modules inserted into IAAC;

placed in stacking fixture

Modules inserted into RTG

Mounting-end MinK insulation

disk inserted

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Capabilities—Process

Radiation Mapping &

Electrical Checks

IAAC opened for entry

RTG removed from IAAC

and transferred to T-cart

Height measurement

completed

Radiation measurements

completed

Electrical checks

completed

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Capabilities—Process

Vibration Testing

RTG mounted for vibration testing

MMRTG subjected to proto-flight vibration test environments in the X, Y, and Z axis orientations

Vibration tests completed

Performance specifications:

Quasi-static acceleration 25 g

Random vibration 0.2 g2/Hz (mean square value to obtain a positive number over a period of time/bandwidth of the filter) gives the Spectral Power Density (output from the accelerometers)

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Capabilities—Process

Mass Properties Testing

The RTG is weighed and then transferred

to mass properties rotation fixture

Requirements:

Mass, including cooling tubes, is

determined and is < 46.5 kg (when

corrected for non-flight parts) and is

known within +0.5 %

Center of Gravity (COG), including

cooling tubes, is measured and shown

to be within 10 mm spherical

tolerance.

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Capabilities—Process

Magnetics Testing

4 magnetometers

RTG placed on magnetic testing station

RTG rotated on Z-axis and magnetic field

measured every 15 degrees

Magnetics Testing Completed

Performance specification: < 25 nT @ 1

meter

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Capabilities—Process

Thermal Vacuum Testing

Power performance data in near

earth space environment

10-6 Torr Vacuum Pressure

-185°C

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Capabilities—Process

Capabilities—Process

Ground Operations at Kennedy Space Center/Cape Canaveral Air Force Station

Safety Analysis—Declare Nuclear Facilities

Transport from INL to KSC in 9904 Type B shipping cask

Integration (Launch -9 Days)

Launch New Horizons: 1/19/06

Closest approach to Pluto--7:49 a.m. EDT on July 14, 2015

Launch Mars Science Laboratory: 11/26/11

Mars Landing: 8/5/12

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INL prepares for NASA’s Mars 2020 Mission

Determine Whether Life

Ever Arose on Mars

Characterize the Climate

of Mars

Characterize the Geology

of Mars

Prepare for Human

Exploration

Science Objectives

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Sample Caching. Collect soil &

rock samples, sample sealing &

storing onboard, depositing

samples on surface.

Sample Return.

Future mission to

return cached samples

to Earth for study.

Nuclear Thermal Propulsion

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NTP Engine Conceptual Design

Historic zero

power critical

testing in ZPPR

NTP fuel testing will be

performed in TREAT

INL is coordinating DOE support for the NASA

Nuclear Thermal Propulsion (NTP) development

program

The current objective for the program is to demonstrate

feasibility of the NTP concept in preparation for a FY

2020 ground test funding decision

INL is coordinating uranium nitride fuel development

work at LANL, instrumentation and control development

work at ORNL, and reactor design work at BWXT Inc.

Integration Preparations are underway for

preliminary testing of NTP fuel samples in TREAT

The first NTP TREAT test will be performed during June

2019 and a second test is planned for May 2020

Post-irradiation examination of the test samples will be

performed at IMCL, NRAD, and the MFC Analytical

Laboratory

Idaho National Lab @INL

Curiosity Rover @MarsCuriosity

NewHorizons2015 @NewHorizons2015 FB https://www.facebook.com/IdahoNationalLaboratory On-Line NASA.gov/missions

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