Atomic Insights Sept 1996

Can you imagine what it would be like to have a battery that could provide continuous power for decades? Amazingly enough, the technology has been in use for more than thirty years with little fanfare and few attempts to market the batteries to the huge commercial market. In this issue we tell you a bit about the history and technology of radioisotope thermal generators.

Letter from the Editor: RTGs, Batteries That Last and Last

It is almost as if NASA, ever cognizant of the need for taxpayer support of its programs, put this useful device “in the closet”, using it when necessary but maintaining an unofficial policy that technical details were best kept from public view.
This issue was inspired by a request from one of our Internet readers for more information about nuclear batteries. It seems that a short article in the April, 1995 issue of AEI was one of the few hits returned on a key word search for the phrase radioisotope thermal generator. He was interested in learning more about batteries that can supply continuous power for 10, 20 or even fifty years.

The more sources that we found, that the more intriguing the search became. Though the technology is several decades old, with a long history of technical success, there is little current activity either by commercial companies or government bodies.

In fact, most companies that we contacted that have previously been in the business of supplying radioisotope generators told us that the market is virtually dead. Some of them are trying to keep some hand in the business by modifying their thermocouple systems to work with other heat sources, while others have abandoned the technology altogether.

The major RTGs user in the United States has been NASA, but you would not know it by visiting NASA sponsored displays at public science museums. The displays often describe the incredibly sophisticated sensing systems that have been sent on exploratory voyages of the solar system, but they rarely mention that the spacecraft depend on a nuclear powered battery to enable the sensors to function and send their information back to earth.

It is almost as if NASA, ever cognizant of the need for taxpayer support of its programs, put this useful device “in the closet”, using it when necessary but maintaining an unofficial policy that technical details were best kept from public view.

Recent Trends

Within the past few months, however, several new web sites sponsored by NASA have been posted that provide more details that previously available to the general public regarding the use of RTGs on the moon and in other missions.

Commercial companies that long ago decided that using RTGs was simply too hard are once again taking a new look to determine if there is some way to quantify just how hard it would be to go through the process of obtaining the needed material and regulatory permits. The incentive for this investigation is the realization that a few carefully placed RTGs might save millions of dollars in electrical cable, fuel supply systems, or chemical battery replacement missions to remote areas.

There is even a rumor that there will soon be a rather lucrative Request For Proposals (RFP) issued by NASA. It is possible that this rumor is based on the growing support for explorations of the surface of Mars.

Our Hope

We hope that this issue, in some small way, contributes to the new openness with which radioisotope generators are being discussed. There may be some new ideas here, possibly even some with commercial potential. Feel free to make contact with us if you have any questions or comments.

Nuclear Batteries: Tools for Space Science

The Apollo missions to the moon are famous for heroic astronauts, exciting first steps and incredible pictures that fired the imaginations of a whole generation of scientists, engineers and school children. Mixed in along with the hoopla about sending men into space on huge, fire spewing rockets, however, was some serious science. Each time the […]

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Earth Bound RTG Systems: Uses Closer to Home

Tiny, milliwatt capacity RTGs found a home inside the chests of middle aged people in countries like France, Russia and even the United States. These devices – about the same size as a AA battery – were designed to power cardiac pacemakers. Not all of the RTGs that have been produced have been designed for […]

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RTG Heat Sources: Two Proven Materials

Strontium is not associated with nuclear weapons and has never been called the most deadly element known to man. There is a precedence in the United States for widely licensing small quantities of sealed Sr-90; it is used in some aircraft ice detection systems.Essentially all RTGs that have been produced have been designed for long […]

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Sources for Atomic Energy Insights September 1996 (RTGs)

Bennett, G. L. et al “Status Report on Radioisotope Thermoelectric Generators using Silicon Germanium Thermoelectric Elements”, paper presented at the 29th Intersociety Energy Conversion Engineering Conference, Monterey CA, 1994. AIAA-94-4127-CP Kelly, E C. and Klee, P. “Cassini RTGs – Small Scale Module Tests”, paper presented at the 29th Intersociety Energy Conversion Engineering Conference, Monterey CA, […]

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Cassini: Near Term Use of RTGs

The only planned use of RTGs in the US space program in the near term is the unmanned, 1997 Cassini mission to explore Saturn. The Cassini spacecraft will be powered by three General Purpose Heat Source Radioisotope Thermal Generators (GPHS RTGs) each designed to provide 276 W of electrical power at the beginning of the […]

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