Canceling the Tour

It was a mission that would have fired the public imagination and severely tested NASA's engineering ingenuity: an eleven-year flight to the very edge of the solar system. On one "Grand Tour," the spaceship would have swooped by Jupiter and with a whiplike assist from that planet's powerful gravitational field, flown past the ringed Saturn and finally Pluto, the outermost planet. In another version, the spacecraft would have used a similar "gravity assist" from Jupiter to swing by Uranus and Neptune instead of Pluto. Scheduled for the late 1970s, the Grand Tours would literally have been once-in-a-lifetime opportunities. The outer planets will not be in such a favorable position again for another 179 years.

Now plans for the far-ranging expeditions have been scrubbed, principally to allow the financially pressed space agency to concentrate on the Administration's multibillion-dollar space-shuttle program; one Tour mission, in contrast, would have cost about $700 million. As an alternative, NASA is considering what it euphemistically calls a "mini-grand tour": a flyby of Jupiter and possibly Saturn using modifications of existing vehicles like Mariner 9, still in orbit around Mars. In fact, such a spacecraft is now being prepared for launch from Cape Kennedy for a two-year flight to Jupiter.

That kind of mission will be much less of a challenge than the Grand Tour. For one thing, it will not require development of the long-lived, self-repairing computer (TIME, Dec. 7, 1970) necessary for an eleven-year mission--a device that could also have had important earthly uses. Beyond that, as President Nixon himself has said, the Grand Tour would have "dramatically expanded" man's knowledge of nature and the universe. Perhaps the most eloquent argument against cancellation comes from one of the bitterly disappointed scientists at Caltech's Jet Propulsion Laboratory, which would have managed the project. "We had a chance to do something unique as a people," says Astronomer Bruce Murray. To him and many of his colleagues, the sudden cancellation of the U.S. venture shows "an incredible lack of vision."

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