Blogs > Cliopatria > NYT wrong to claim that polonium-210 once was used to power US spacecraft

Dec 14, 2006 7:18 pm


NYT wrong to claim that polonium-210 once was used to power US spacecraft



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 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 (at page 4):

http://www.fas.org/nuke/space/mound.pdf

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 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):

http://www.fas.org/nuke/space/history.pdf

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.



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