Remember Voyager?

That is the unmanned space probe the National Aeronautics and Space Administration launched in September 1977. Since then Voyager has starred in at least two movies, discovered 26 moons orbiting various planets and, most recently, sent photographs of Uranus that are out of this world.

Voyager's timing, however, was wretched. The triumph at Uranus came just as the shuttle Challenger exploded Jan. 28 and killed its crew of seven. "Our press evaporated," moaned Voyager project director Richard Laeser at NASA's Jet Propulsion Laboratory here.

The loss of publicity for an unmanned scientific space venture, long the poor cousin in the nation's exploration of the heavens, was just the beginning of the cost the scientific community will pay because of the shuttle explosion.

With the shuttle grounded and other rocket systems broken, once-in-a-lifetime launch dates have come and gone and the competition is increasing to find bookings on future launches. Scientists worry that the Pentagon will preempt most nonmilitary launches, particularly when it gets into heavy testing of President Reagan's Strategic Defense Initiative, also known as "Star Wars."

As for NASA, its first priority after recovering from the shuttle disaster will be to push its long-time goal of building and supplying a space station, which will also require many shuttle missions.

As a result, the space science community is concerned about keeping its best people and attracting new blood at a time when the future at best is murky. "If young people perceive that space is not where the action is, we'll lose them," said Frank B. McDonald, NASA's chief scientist.

The last major U.S. scientific space probe -- Pioneer to Venus -- was launched in 1978. It seems probable that the next one will be at least a decade later.

Several scientific programs, including a major U.S. probe of Halley's comet, were eliminated from the NASA budget by the Reagan administration in 1981 in what one scientist described as the "slaughter of the innocents." Two major new efforts scheduled for launch in May have been delayed for uncertain months, if they ever go.

"What happens is we're going to be several years late starting new missions, we're going to be marking time . . . , " McDonald said. "We're losing a great deal of momentum in a high-visibility area."

Nonetheless and despite budgetary pressures, scientific space missions will remain an important part of NASA, McDonald and other NASA officials said. Science programs take about 10 percent of NASA's $7.5 billion annual budget.

Lost on the Challenger were several experiments and a satellite relay station needed to make functional a future, but now postponed, telescope in space. Lost in the aftermath were the two launches scheduled in May for the scientific missions named Ulysses and Galileo.

Ulysses is supposed to fly by Jupiter, where it will pick up a gravity boost to carry it out of the planetary plane and on top of the poles of the sun, never before seen from that angle. Galileo is to orbit Jupiter and send a probe into that planet's atmosphere. Both missions are time sensitive -- they had to be launched last month to take advantage of the Earth's position relative to Jupiter.

The next window of opportunity for Galileo is December 1987; Ulysses could be launched in July 1988. However, both require a working shuttle, and it is unclear how long it will take NASA to meet recommendations of the Rogers commission on making the shuttle safer.

Both missions also present new challenges for the shuttle. Ulysses and Galileo are to be launched from the shuttle's cargo bay by a previously untried liquid-fueled upper-stage booster system, and both must carry a nuclear source of electricity because they will travel too far from the sun to use solar cells.

Those circumstances have regenerated safety questions after the shuttle explosion and the Soviet power plant disaster at Chernobyl, such as, what happens if the radioactive power supply for Ulysses or Galileo gets scattered across the countryside in another shuttle explosion? Although NASA officials say they think they can handle the problem, they will have to answer more questions in advance about safety than they have in the past.

Tom Donahue, a professor at the University of Michigan who is an experimenter on the Galileo project, noted that the earliest Galileo could reach Saturn after a December 1987 launch would be late 1992 or early 1993. "I'm 65 years old," he said. "I'll be 71 or so, so the shuttle loss sure makes a difference to me . . . . The lifetime of a graduate student is about five years. How can people devote their time to the space program when they need to produce research?"

Donahue said, "We've been living with this since the decision to reduce the space program and use the shuttle as the only means of access to space for all activities."

Asked how he would justify purely scientific space missions, he said, "All that we're offering is a possibility of understanding how the universe got here, how it was formed, how it was developed. If mankind doesn't need that kind of information, then I'm very sorry for mankind."

Donahue is chairman of the National Academy of Sciences' space sciences board, but stressed he was speaking as an individual.

Chester M. Lee, director of customer services for NASA, said the agency has held discussions with the Defense Department and other shuttle customers and that "we've been able to work out something that seems acceptable." He said that while national security is the first priority in assigning launch dates, "that doesn't mean the first 10 payloads will be all Defense Department."

The shuttle can carry an assortment of cargo, depending on size and weight, and it will be possible to fit scientific loads around Pentagon satellites on the same shuttle mission, he said.

The second priority, he said, is to complete the satellite relay system needed for the space telescope. An important component of that system was lost in the Challenger explosion and will have to be replaced. Third comes Galileo, fourth is the space telescope itself.

While schedules are being drawn to take care of everybody, there is no question that "the science community is hurt, DOD is hurt, everybody's hurt," Lee said.

Galileo, Ulysses and the space telescope are just three of many scientific projects on the NASA drawing board that have been designed to fly on the shuttle. Just as the Pentagon and commercial users are beginning to look fondly again at old-fashioned throwaway rockets as launch vehicles, the scientific community is too. But for the short-term, the shuttle is it.

The loss of the Challenger "is a major disaster for the astronomical community," said Peter B. Boyce, executive officer of the American Astronomical Society. He said that "at the very least" there will be a two-year delay, and it will cause ripples.

For example, the Venus Radar Mapper, a spacecraft that is to do just what it sounds like, was to be constructed from spare parts for the Galileo mission. With Galileo stalled, the spare parts bin cannot be used.

With the near-term future for scientific launches in limbo, those decade-old Voyagers and a remarkable series of radio antennas called the Deep Space Tracking Network operated by the Jet Propulsion Laboratory (JPL) promise to continue producing scientific data.

The Voyager story is one of enormous engineering achievement, the sort of good news NASA and its agencies publicize well. JPL is almost, but not quite, a NASA center like Kennedy and Johnson. JPL is run for NASA by the California Institute of Technology, and therein lies the difference: Its employes are not civil servants.

There are two Voyagers, and both visited Jupter and Saturn between 1979 and 1981. Voyager 1 is traveling out of the solar system and will not meet another planet in the system, although it is still in radio contact with JPL. Voyager 2 flew by Uranus in January and is to fly past Neptune in August 1989.

"This spacecraft could die at any moment," project manager Laeser said. "One of the management challenges is to keep everybody on their toes so we don't make that fatal mistake. We could kill Voyager easily. How are we going to avoid that with four years between planets? We've concluded that a mix of old and new people is needed and that paranoia is a virtue. We check each other constantly."

Voyager is already half dead. One of its two radios quit shortly after launch and the other is severely crippled. JPL's experts have figured how to transmit and receive information, including those photos of previously undiscovered moons and strong evidence that Uranus is covered by an ocean of superheated water 5,000 miles deep.

"We have a pretty strong constituency, from science fiction freaks to legitimate scientists to people who have the spirit of the explorer," Laesar said. "This is the age of exploration with robots. Why should you close down something that has this almost universal appeal? It excites me that in two of my kid's textbooks I have seen pictures that our spacecraft has taken."