# Historical RTG Performance Data Through 2020
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Usage Clause - The authors collected and curated this data on their own time and are making the numerical format freely available to all (i.e. no copyright).  We only ask that any publication, report, or presentation that directly, or indirectly, uses any values from this dataset reference the book where this data is presented in a copyrighted graphical format. 

**Please Reference:  C.E. Whiting and D.F. Woerner, "Chapter 8: Lifetime Performance of Spaceborne RTGs," The Technology of Discovery: Radioisotope Thermoelectric Generators and Thermoelectric Technologies for Space Exploration, D.F. Woerner, Ed., John Wiley & Sons, 2023. ISBN: 9781119811367)**

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Brief Description:
This dataset contains all of the available power and performance data for RTGs that have been flown in space through early 2020.  Power values for RTG performance were collected from reputable and authoritative sources, and organized into a tabular format of time versus normalized electrical power.  Normalized electrical power is the power at a given time, divided by the power at the beginning-of-mission (BOM). BOM power for each mission is also provided.  Some important pieces of context for each RTG mission are also provided above the table.

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Description of the data and file structure:
Data is and organized into an Excel spreadsheet that contains several tables that present the RTG performance data.  Each major RTG design has its own table.  Each table is presented in a separate tab.  One tab also collates all of the tables and presents them in a single tab.  Data in the individual tabs and the collated tab are identical.

Within each table, performance data for each RTG mission is presented as time versus normalized electrical power.  Normalized electrical power is the power at a given time, divided by the power at the beginning-of-mission (BOM).  BOM power for each mission is also provided.

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Usage Context:
Performance data for RTGs is highly dependent on the RTG design and specific mission characteristics.  It is not possible to completely outline all of the important context needed to fully appreciate this data in a simple dataset.  Therefore, the user is highly encouraged to access the book cited at the beginning of this document.  This book provides all the context necessary to make full use of and understand this dataset.

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Pedigree of the data:
RTG’s have a very long and storied history (60+ years), but the entities in charge of monitoring and managing the power data from RTGs is not consistent.  Sometimes, the Department of Energy (or its predecessor, the Atomic Energy Commission) was in charge of maintaining RTG power data.  Sometimes, NASA was in charge of maintaining the data.  Sometimes, the various mission control centers were in charge of maintaining the data.  This has created a lot of confusion regarding the ownership and quality of power data for many RTGs.  In many cases, some of the data was never published at all (e.g. Galileo after 8 years and Pioneer after 18 years).  It is therefore understandable that the pedigree of this data is described in detail, especially the data that has never been openly published previously.

SNAP-9A, SNAP-19 (Nimbus III, Viking 1, and Viking 2), SNAP-27, and Transit-RTG were obtained from graphs presented in G.L. Bennett, J.L. Lombardo, and B.L. Rock, “US Radioisotope Thermoelectric Generators in Space,” Nucl. Eng., 25(2), 49–58 (1984).

SNAP-19 (Pioneer 10 and 11) were obtained from an internal memo published by Teledyne Energy Systems, Inc. (courtesey T. Hammel).  Teledyne was the design and engineering agency in charge of the SNAP-19.

MHW-RTG (LES 8 and 9) were obtained from the Cassini Final Technical Report (DOE/SF/18852-T97) published by Lockheed Martin.  Lockheed was the prime contractor and system integrator for all silicon germanium RTGs (i.e. MHW-RTG and GPHS-RTG) at that time.

MHW-RTG (Voyager 1 and 2), GPHS-RTG (Galileo and Cassini), and MMRTG were obtained directly from the mission control at the Jet Propulsion Laboratory.

GPHS-RTG (Ulysses) was obtained from the Mission Operations Manager N. Angold.

GPHS-RTG (New Horizons) was obtained directly from the mission control at the Applied Physics Laboratory.
