Nuclear Weapons

Polonium and the History of Space Nuclear Power

12.14.06 | 3 min read | Text by Steven Aftergood

Updated Below

When the New York Times mentioned in passing recently that polonium-210 had once been used to power U.S. spacecraft, it caused a furrowing of the brow among the seven or so people who dwell on the history of space nuclear power, since it is almost certainly not correct.

“President Eisenhower, eager to promote ‘atoms for peace,’ had the high heats of polonium 210 turned into electricity for satellites,” wrote the estimable William J. Broad in a recent Times Week in Review piece (“Polonium, $22.50 Plus Tax,” December 3). “But the batteries lost power relatively fast because of the material’s short half-life, just 138 days. The United States made few such spacecraft.”

Not so, according to Gary L. Bennett, who devoted much of his career at the Department of Energy and NASA to the development of space nuclear power sources.

“As far as I know, the U.S. never flew a spacecraft powered by polonium-210,” Dr. Bennett told Secrecy News.

Dr. Bennett identified one documentary source (pdf) that claimed otherwise, a history of isotope production at the Mound Laboratory in Ohio. It is consistent with the New York Times account, but he said it too was in error.

That Mound history described the use of polonium in an early radioisotope power supply called SNAP 3A:

“The first SNAP-3A, fueled with polonium-210, provided power to a satellite radio transmitter. The use of satellites powered by SNAP for global communication was first demonstrated under President Eisenhower in 1961, at which time the President’s peace message was broadcast via a satellite containing a radio transmitter powered by the SNAP-3A RTG.” See here (at page 4).

But all other historical accounts agree that the first SNAP-3A was launched on June 29, 1961 (on the Transit 4A spacecraft), after President Eisenhower had left office, and it was fueled with plutonium-238, not polonium-210.

It is true that the SNAP-3A was originally designed with polonium fuel, because of Atomic Energy Commission restrictions on plutonium, according to a deeply researched official history of space nuclear power (very large pdf) prepared for the Department of Energy.

A photograph of President Eisenhower in the Oval Office enthusiastically examining a polonium-fueled SNAP battery appeared on the front page of the Washington Evening Star on January 16, 1959. (“Nuclear critic Ralph Lapp complained that a highly lethal item had been placed on the President’s desk.”)

But “the AEC eventually relaxed its policy and agreed to provide the plutonium fuel and SNAP-3A, as a result, was converted from polonium-210 to plutonium-238,” the official history stated (at page 23).

“Despite the president’s enthusiasm [in January 1959], the first RTG [radioisotope thermoelectric generator] flight came two and a half years after the White House demonstration,” the official DOE history states (page 18).

It was the plutonium-fueled version that was launched into space in June 1961, not the original polonium-fueled design.

See “Atomic Power in Space: A History,” prepared for U.S. Department of Energy, March 1987 (188 pages, 8.5 MB).

Polonium-fueled radioisotope power or heater units were used on spacecraft launched by the former Soviet Union on a number of occasions, Dr. Bennett noted.

Update: To its credit, the New York Times ran the following correction on December 17:

“An article on Dec. 3 about the many uses of polonium 210 referred incorrectly to the radioactive material utilized in early American satellites. While plans were drawn up to use polonium 210 as a power source, and one federal document said it was used, nuclear experts say that the government decided instead to rely on plutonium 238; no American satellites ever flew with polonium 210.”

publications
See all publications
Nuclear Weapons
Report
Nuclear Notebook: Russian Nuclear Weapons, 2023

The FAS Nuclear Notebook is one of the most widely sourced reference materials worldwide for reliable information about the status of nuclear weapons, and has been published in the Bulletin of the Atomic Scientists since 1987.. The Nuclear Notebook is researched and written by the staff of the Federation of American Scientists’ Nuclear Information Project: Director Hans […]

05.08.23 | 1 min read
read more
Nuclear Weapons
Blog
Video Indicates that Lida Air Base Might Get Russian “Nuclear Sharing” Mission in Belarus

On 14 April 2023, the Belarusian Ministry of Defence released a short video of a Su-25 pilot explaining his new role in delivering “special [nuclear] munitions” following his training in Russia. The features seen in the video, as well as several other open-source clues, suggest that Lida Air Base––located only 40 kilometers from the Lithuanian border and the […]

04.19.23 | 7 min read
read more
Nuclear Weapons
Blog
Was There a U.S. Nuclear Weapons Accident At a Dutch Air Base? [no, it was training, see update below]

A photo in a Los Alamos National Laboratory (LANL) student briefing from 2022 shows four people inspecting what appears to be a damaged B61 nuclear bomb.

04.03.23 | 7 min read
read more
Nuclear Weapons
Blog
STRATCOM Says China Has More ICBM Launchers Than The United States – We Have Questions

In early-February 2023, the Wall Street Journal reported that U.S. Strategic Command (STRATCOM) had informed Congress that China now has more launchers for Intercontinental Ballistic Missiles (ICBMs) than the United States. The report is the latest in a serious of revelations over the past four years about China’s growing nuclear weapons arsenal and the deepening […]

02.10.23 | 6 min read
read more