September 26, 1997
The Honorable William Jefferson Clinton
President of the United States
The White House
Washington, DC 20500
Dear President Clinton:
We write to urge you to call for the postponement of the Cassini space probe, due to be launched on October 6th, 1997, until we can be assured that the risk of tragic results should an accident occur is not present.
The Cassini probe is due to carry 72.3 pounds of Plutonium-238 a potentially deadly radioactive material. Prominent scientists, including a former NASA safety official, as well as respected investigative environmental reporter Karl Grossman, have argued convincingly that the plutonium is not adequately shielded, and could pose serious danger should the probe explode at the time of its launch or later in the mission while the probe is approaching orbit.
While some have argued that an accident is highly unlikely, the 1986 Challenger tragedy and other recent incidents should serve to remind us of the dangers that can exist. The threat of plutonium release is present not only at the launch of the Cassini space probe. There is also potential danger to the population of Earth at various points throughout the mission, including the probe's "flyby" of Earth planned for 1999.
Considering the risk that nuclear materials pose to humans, regardless of how carefully designed and managed by NASA, we believe that alternative energy sources must be considered. For instance, the dramatic advances in solar technology over the last several years clearly demonstrate its potential as a power source. While solar energy may not be appropriate for a launch as early as October, we ask that you seriously consider postponing the launch of Cassini until other mission options have been thoroughly examined and researched.
While we have much to learn through the exploration of space, in this instance the grave potential danger posed by the plutonium on the probe would seem to outweigh the potential benefit from this mission. It is too important to squander the public's trust on such a risky mission. A NASA that all Americans can support instills hope for the future, not fear of tragedy.
Thank you for your consideration of this matter. We look forward to knowing of your views on this important issue.
(signed by 15 members of Congress)
Lynn C. Woolsey
Ronald V. Dellums
Peter A. DeFazio
Fortney Pete Stark
John W. Olver