The Cassini Gamble

The U.S. National Aeronautics and Space Administration launched a space ship on October 15, 1997 on a 7-year flight to study the distant planet Saturn in hope of "understanding the birth and evolution of our solar system," (from Final Environmental Impact Statement, FEIS, June 1997, page 1). However, because the ship contains 72 pounds of radioactive Plutonium (P-238), it poses a major public health threat if NASA follows through with its plans to return it from Venus to circle Earth (for a so-called Earth Fly-By) to increase its speed on route to Saturn.

Federal regulations require an independent evaluation whenever radioactive material is introduced into space. A Nuclear Safety Review Panel consisting of a representative of the U.S. EPA, Dept. of Energy, Dept. of Defense, the Nuclear Regulatory Commission and NASA issued a Safety Evaluation Report (SER) July 1997, which noted major discrepancies in the various Environmental Impact Statements by NASA:

1. NASA claimed the Plutonium containers "were designed to withstand re-entry" into our atmosphere (FEIS p. 2-17 et al.). Yet the SER noted that they were not designed to withstand the heat of an accidental re-entry at the planned flyby-by speed of 10 miles per second (p. 3-24).

2. NASA claimed that almost none of the Plutonium could become airborne in any accident (FEIS-Supplemental p. E-95). In contrast the SER notes that 9 kilograms could become airborne in respirable form, the only hazardous state (p. 3-19).

3. NASA estimated that in the event of an accident the Plutonium could cause 120 fatal cancers (Final Supplemental EIS, p.4-9). Yet, the SER states "tens of thousands" cancer deaths could result from a major accident (p. ES-4).

4. NASA discusses the cancer-causing potential of Plutonium on the basis of the cancer dose from general ionizing radiation. Yet the SER notes "the probability of a single inhaled particle inducing a cancer" (P. 3-12). This was reported in the Proceedings of the National Academy of Sciences (April 1997) from experiments performed at Columbia University, financed in part by NASA, yet completely ignored in all their EIS's. The SER however omits mentioning that each kilogram of Plutonium contains trillions of radioactive atoms, and the number of fatal cancers might be many times greater than the tens of thousands estimated by the SER.

5. NASA claims the chance of an accidental re-entry of the space-ship into our atmosphere is less than one in a million. Yet a Jet Propulsion Lab report (May 1997) lists 18 different types of malfunctions that may occur, including electrical short-circuits, meteors and space debris striking the space probe, and erroneous ground commands. At the planned Fly-By speed of 10 miles per second, a loss of control lasting only 42 seconds could result in the Cassini's re-entry into our atmosphere where the ship will burn up.

In view of the multiple major conflicts between NASA's claims and the SER findings, and NASA's gross error in the carcinogenicity of Plutonium, NASA should not be permitted to risk thousands of civilian lives by the Flyb-By without an evaluation by an independent scientific group such as the National Academy of Sciences. A recent report by the Government Accounting Office merely repeated NASA's claims, but completely ignored the findings of the SER.


Earl Budin, M.D., Former Assoc.Clin.Prof.Radiology (805-965-7327)
F.H. Knelman, Ph.D., Former Prof. Env. Studies
N. Meshkati, Ph.D., Assoc. Prof.Civil Engin. (213-740-8765)

Last revision: 3/7/99 3:47:48 PM