science floor - lunar and planetary institute · science floor emmrtg discretionary energy for msl...

~8.5 yrs of constant energy for science operations from the eMMRTG relative to the MSL Mission Design

2 times the energy of the MMRTG per sol at ~5.5 yrs

The eMMRTG still produces 78% of the discretionary energy the MMRTG produced at landing at EODL

MSL used a linear degradation for conservatism; the RTG community typically uses an exponential decay rate for RTG power degradation

Science Floor

eMMRTG Discretionary Energy for MSL

BOL – Beginning Of Life, fueling EDL – Entry, Descent, and Landing EODL – End Of Design Life, 17 yrs from BOL

If MSL had an eMMRTG

Five Take Away Points 1.  Increased EODL power, 80-100% more than MMRTG 2.  Graceful degradation 3.  Quiescent power 4.  Operates in vacuum and planetary atmospheres 5.  Enhanced RPS Power in a flight-proven package; rugged

David Woerner: JPL/California Institute of Technology david.f.woerner@jpl.nasa.gov

Office: 818-393-2000 Cell: 626-497-8451

SKD couples Advanced SKD MMRTG modules

Skutterudite (SKD) materials

Liner changes boost operating temperature

Operating temperature rises from 520C to 600C

enhanced MMRTG

New SKD materials with higher performance and maximum operating temperature than MMRTG TE materials

+ 10% increase in conversion efficiency over MMRTG couples

14% increase in conversion efficiency over MMRTG couples

24% increase in conversion efficiency over MMRTG

MMRTG enhanced MMRTG enhancement BOL Power (W) 122 * ~166 ** 36%

Power at EODL (W) 54 ~109 101%

Degradation Rate *** 4.8% 2.5% ~ 2x

No. of GPHS Bricks 8 8

No. of Couples 768 768

Hot Junction Temp 520 oC 600 oC

Cold Junction Temp ~170 oC ~170 oC

Mission Usage Multi-Mission Multi-Mission

Development Risk None Low – Moderate

Addressed Program MSL and Mars 2020 Europa, Discovery, New Frontiers

BOL – Beginning Of Life, fueling EDL – Entry, Descent, and Landing EODL – End Of Design Life, 17 yrs from BOL

* 28V, Thermal Inventory = 250 Wth; 4k thermal sink ** 32V, Thermal Inventory = 250 Wth, 4k thermal sink

*** Steady-state thermal sink, Mars hot case

JPL Led Technology Maturation (TechMat) DOE Led Flight Development

SKD Tech Maturation

Sys Risk Reduction

Module

Decision Gate 1

F4 F5

F6 F7

Start Flight Program Based on Acceptable Risk Level

Decision Gate 2

Launch

Design Qual Unit

Testing

Notional Schedule

Flight Development Gate

Notional Schedule Provided for Reference Only

eMMRTG Sys Eng

FY17 FY18 FY16 FY15 FY19 FY20 FY21 FY22 FY23 FY24 FY14

Launch

Low Risk Enhancements Are there potential customers in PSD’s Decadal Survey?

1 – 4 eMMRTGs

1 – 6 eMMRTGs

Data courtesy of RPS Program’s Mission Analysis Team

The MMRTG plus these highlighted

changes

What is being enhanced?

And many more that could benefit from the eMMRTG

were excluded from the Survey

results.

Technology Transfer & Maturation + MMRTG design mods = eMMRTG

PRESS RELEASE

Pre-Decisional Information -- For Planning and Discussion Purposes Only""