TV REVIEW : Voyagers’ ‘Tour’ Brings Joy and Sadness : Television: Two ‘Nova’ specials explore the first good look at far-away worlds and the explorers that took us there.

The “grand tour” of the outer planets by the two Voyager spacecraft was both the beginning and the end of an era.

The unmanned robots marked the first attempt by humans to explore the back yard of the solar system, including the huge gaseous planets that orbit many times farther from the sun than the Earth, and their sometimes baffling moons and glorious rings. But it also signaled the end of of what astronomer Carl Sagan calls the reconnaissance of the solar system, the first good look at worlds we had seen only through a glass so darkly.

There is in that duality both joy and sadness. The twin journeys by the two craft rank among the most successful engineering feats of all time, and they brought the joy of discovery to armchair explorers around the world. But never again will we have the thrill of that first look at these distant, mysterious worlds. Some day others will look more closely, but never again will anyone see them for the first time.

The public-television series “Nova” explores the wizardry that was Voyager in two one-hour shows on consecutive Tuesdays, beginning tonight at 8 on Channels 28 and 15, at 10 on Channel 50.

The first installment, “Neptune’s Cold Fury,” features the last stop on Voyager II’s journey: Neptune, now the most distant planet in the solar system because Pluto’s elongated orbit carries it inside Neptune’s path. The second installment, to be aired Oct. 16, is the fuller story of the expedition to the outer planets by the remarkable robots.

Both shows are fitting tributes to the Voyagers and to the men and women of NASA’s Jet Propulsion Laboratory in Pasadena who made the miracles happen.

The spacecraft forced experts to rewrite the textbooks on the solar system, and the data that they sent back to Earth will have to suffice for a long time into the future. It is unlikely that many who read these words today will live long enough to see another journey to such fantasy lands as Neptune and Uranus. There are no missions even in the early planning stages to send other robots to these distant bodies, and the celestial mechanics of getting there virtually rule out any effort for many decades.

So we must make do with what we have. But what an enormous treasure chest the two Voyager’s provided.

The Voyagers, launched from Florida in the summer of 1977, were twins, and they were designed initially to visit only Jupiter and Saturn. NASA built two spacecraft so that if one failed, the other could complete the mission, a philosophy that has been discarded by a more budget-conscious agency. Both craft carried out the complete mission, but at Saturn, Voyager II was given a new assignment. By using the gravity of that giant ball of gas, the small craft slingshotted itself out toward Uranus, extending its mission far beyond what it was designed to do.

No one was sure then that the mission was even possible, and “Nova” does its best to recapture the suspense of scientists and engineers who wondered whether they might stumble in front of a worldwide audience. While the result is a little like watching the replay of a ballgame when you already know the score, some of the anxiety still comes through.

“Nova” does add the dimension that it uses so well: allowing scientists to explain their work with vivid graphics and high school level experiments that clearly reveal such things as why Jupiter’s exotic moon, Io, is a patchwork of various shades of red. The enhanced images from JPL, depicting what the visits would have looked like to someone fortunate enough to have been riding aboard the spacecraft, capture much of the excitement that scientists with their trained eyes saw in the first fuzzy images beamed by Voyager to television monitors at the Pasadena lab.

Yet while the Voyager expedition was “unmanned” in the sense that no one was aboard either craft, the grand tour was a deeply personal experience for many. During the 12-year journey of Voyager II, a young scientist by the name of Edward Stone grew gray and even more eloquent. Stone, now vice president of Caltech, will take over as director of JPL this December.

And there is a young Andy Ingersoll, first appearing with a beard so long it looks as though he could step on it, and now a clean-shaven, distinguished scientist who is still struggling to understand the atmospheric dynamics of the distant planets.

These and so many others have grown older and wiser because of the Voyagers, and it is a little haunting to see them age so quickly in the second program. Many others who played key roles have retired, and some have died during the 13 years since the journey began.

None of them will ever again see anything that will rival the grand tour delivered by the Voyagers. They had the good fortune of being there when history was made, sharing in an expedition that even their own teachers could only dream about.

Both Voyagers are now on their way out of the solar system to journey through space. Their radios will be silenced by time, but they will travel on, remnants of a brief, historic time when humans reached beyond their world for the stars.