Cassini's Night Ride
When thou seest an Eagle, thou seest a portion of Genius. lift up thy head!
We live in an era of exciting unmanned space projects: the Mars Pathfinder; the Chandra space telescope; Deep Space One. Tuesday, at 11:28 Eastern time, perhaps the most fascinating of them all, the Cassini probe, visits Earth, apparently for no more than 35 seconds, before wheeling outward toward its 2004 rendezvous with Saturn. Its flashing in at 35,000 mph; itll pick up an extra 11,000 by slinging round the Earth.
Cassini, a NASA craft HQd out at JPL, will achieve Saturn orbit sometime in November, 2004. At some point it will deposit the Huygens space probe, compliments of the European Space Agency, which will parachute into Titans atmosphere, measuring its pressure, temperature, and density. Tonight is our last chance to be near these probes till, one day, we follow their trail.
Adding to the intrigue is the possibility that Cassini could disintegrate in the upper atmosphere and hasten all our deaths. It carries 72 pounds of plutonium. One Arjun Makhijani, a nuclear engineer from the Institute for Energy and Environmental Research, claims that if Cassinis plutonium vaporized in our atmosphere it could release more radiation than all the open-air nuclear explosions since the very first Los Alamos blast in 1945, combined. This would be very serious business: Berkeley professor and Manhattan Project veteran John Gefman, who has an MD as well as a PhD, attributes an increase in lung cancer since the mid-1960s to the TRANSMIT 5BN-3 spacecraft, which fell back to Earth in 1964, and which carried about a third the plutonium Cassinis packing.
Michio Kaku, a man sufficiently visionary to be one of the first popular champions of string theory (I refer to his fine book, Hyperspace), has been perhaps even more vigorous in his denouncing of Cassini. He has written extensively-to a nonscientist such as myself, numbingly-about the potential dangers. Peace activists who protested Cassinis launch now protest the flyby; theyll be out tonight, you can count on it. These are people many are quick to dismiss, but, having marched with them a few times on other causes, I find it difficult to do so. I do find in them a nearly mystical fear of anything nuclear, and their propensity to link Cassini to a general "militarization of space" seems absurd. At the end of the day, though, Im in something like their position: a nonscientist picking among the conflicting testimonies of scientists in order to support my opinion about a scientific project.
The pro-Cassini side has some solid scientific credentials of its own. NASA can claim to have safely used radioisotopic thermoelectric generators-the "nukes" under discussion-on its Apollo, Pioneer, Viking, Voyager, Galileo and Ulysses missions. No incident. No problem. NASAs estimation of the odds for a failure in Earths upper atmosphere are 1 in 1.2 million. Bob Mitchell, Cassinis Program Manager, has said of such a failure, "Its not a credible event. Im not telling you its impossible, but its just not credible." Apparently the anti-Cassini faction has been saying that the nuclear-powered RTGs could have been replaced by solar cells; NASAs response is that solar cells just wont work as far out as Saturn because of the faintness of the suns energy at such a distance.
This puts me, and, perhaps, you, back in the ring with the peace activists, picking scientists. Finally, the act of choice, for myself and for national policy generally, must fall back upon personal preference:
Do you choose to favor this supremely cool mission, and accept the risk that it might, just might, lead to the deaths of millions by cancer? I do. Im not entirely comfortable with the choice, but Im not going to lose any sleep over it, either. It would be easy to theatricalize such a concern, to convey, through writing, something akin to Bill Clintons quivering bottom lip, but I wont do that. Ill be blunt: I want this mission, and will choose to believe the scientists who say there aint gon be no accident. I know Im "picking scientists" when I want Kaku to be wrong about Cassini but right about string theory. If youre pro-Cassini, and not, yourself, a scientist, you probably feel the same way. You may nod in mock-sympathy when confronted by someone deeply concerned about the projects dangers, but on the inside, youre lying. We are both inwardly delighted that no protest is going to stop this mission (and while were being honest, lets not pretend that the protests failure has anything to do with a general public interest in space exploration. Cassini benefits not from our enthusiasm, but from the publics indifference). Even deeper within us rests a conviction that we dont dare speak: that the success of this mission would, in the long run, do more for humanity than its failure would cost us, even if that failure be measured in human lives.
(Something, though, must voice this position, or mark my words, were going to lose space exploration-and that something might well be a philosophically and artistically serious Hard Science Fiction. Dan Goldin, space sciences left jab, cant hold off the mundane forever.)
So I hope you got out in spirit Tuesday night, brethren. We might not say whats in our hearts, but we can stand up for ourselves.
(Todd Jackson teaches a course in Science Fiction at Goucher College in Baltimore, Maryland, while writing the first of a series of African-American science fiction novels, titled The Lou Douglas Network.)