1989 Expected to Be an ‘Unparalleled’ Year for Space Science Missions

After all the fretting about the demise of space science in the aftermath of the Challenger disaster, the National Aeronautics and Space Administration is gearing up for a series of science missions that will be “unparalleled” in the history of the space program.

The use of expendable rockets by the Defense Department, NASA and the commercial sector to launch payloads into orbit has eased the burden on the shuttle, making it available for more scientific missions, and the space agency has assigned a higher priority to science than had been expected by most observers.

Next year, which will be the first full year of operations after the shuttle begins flying again, will bring “a sudden re-mergence of space science” because of a backlog of scientific projects that have been sitting in warehouses waiting for the shuttle to begin flying again, said Lennard A. Fisk, NASA’s chief scientist.

New Era Foreseen

Resumption of shuttle operations--scheduled to begin with the first flight around the end of August--coupled with renewed use of unmanned, expendable rockets, will usher in “one of the most exciting periods in space science that this nation has ever seen,” Fisk said during a recent conference here. The year is to be highlighted by the launching of the Hubble Space Telescope, destined to become the centerpiece of an aggressive effort to study the universe with orbiting observatories, plus the launching of two planetary probes, one to Venus and one to Jupiter.

And in the midst of it all, a grand old friend among space scientists, the Voyager, will arrive at its fourth planet--Neptune--to give humans their first close look at the eighth planet from the sun. That encounter will take place in late August of next year even if the shuttle never gets off the ground again, because Voyager was launched on its spectacular odyssey more than a decade ago.

Even Louis Friedman, executive director of the Pasadena-based Planetary Society and a longtime critic of NASA over its faltering planetary program, concedes, “Great stuff is coming up . . . if--and it’s a very big if-- there are no delays.”

Strict Timetable

Much of the success of 1989 depends on the shuttle resuming operations this fall. Any significant slip past early September could force NASA to reshuffle some of the projects, although it seems likely that enough missions will be launched next year to keep scientists busy for many years to come.

That is fortunate, because space science projects thin out dramatically in the early 1990s, and demands on the shuttle for both Defense Department missions and construction of the space station will severely limit the number of flights that can be made for purely scientific objectives, according to many sources within the space agency.

Still, the future does not look nearly as bleak as many had feared, due partly to a fundamental change in the nation’s space program. Before the explosion of the Challenger in January, 1986, both the Defense Department and NASA were under orders to use the shuttle as the sole means of getting to space, and expendable launch vehicles that had served the country so well in the past were being phased out.

But as a result of the Challenger tragedy, that policy has been reversed and expendable rockets are to be used extensively in the future, especially whenever a manned presence in space is not essential to the mission. The Defense Department, which was never too fond of the shuttle, has embraced that change with gusto and is pushing for a new generation of expendable rockets. NASA is also moving in that direction, but more slowly.

Appropriately enough, the first scientific mission to be launched since the Challenger disaster will be carried into orbit next February on an expendable rocket.

The Cosmic Background Explorer is designed to “look at radiation left over from the beginning of the universe,” Fisk said.

The Big Bang, which most scientists believe started it all, is believed to have released enormous amounts of radiation, some of which is distributed throughout the universe. By studying that radiation, called the “background,” scientists hope to learn more about the universe in its earliest stages.

Venus Mapping Project

The shuttle will reenter the space science arena next April when it is scheduled to launch the Magellan Venus Radar Mapper. A satellite launched by the shuttle spins for stability as it is released from a canister in the cargo bay. After it drifts a safe distance from the shuttle, which usually takes about an hour, the satellite’s solid-fuel rockets fire, sending it on its way.

“That will be the first planetary launch in a decade,” Fisk said, restating a fact that has been a source of extreme frustration for planetary scientists. After essentially inventing the field of planetary probes, the United States backed off from one of its most productive areas, and in recent years the Soviet Union has aggressively moved into the field. The Soviets are planning a series of unmanned missions to Mars beginning in July and extending through the end of the century. (Soviet leader Mikhail Gorbachev recently proposed that the United States and the Soviet Union participate in a joint venture to Mars, and that proposal is now being studied at NASA headquarters.)

The Jet Propulsion Laboratory’s Magellan mission will be a small step toward reasserting U.S. presence in the planetary sciences. Using radar to peek beneath the clouds that envelop the planet, the probe will systematically map nearly the entire surface of Venus.

The April launch is critical because if it is not launched then it will have to wait 20 months for the next “window” that would permit it to fly to Venus. Because of that severe penalty, Magellan has a high priority within NASA, Fisk said, and every effort will be made to launch it in April even if some major missions have to be reshuffled.

And next June, if all goes according to plan, the Hubble Space Telescope will be launched into orbit. Space Telescope, built at a cost of $1.2 billion, was to have been launched two years ago, and the cost of maintaining the telescope during this long hiatus has pushed the investment well above $2 billion, making it by far the most expensive scientific instrument this nation has ever built.

A Critical Look

Orbiting above the distorting effects of the Earth’s atmosphere, and viewing the universe through wavelengths of light that do not even reach the ground, Space Telescope will give astronomers a precious tool. It’s super-sharp images should reveal celestial treasures that are too small, or two distant, or too faint to be seen any other way.

The Space Telescope will be “a billion times” more sensitive than the unaided eye, Fisk said, and it should usher in a new era in astronomy, finding new treasures in deep space. Astronomers on the ground will follow up on those discoveries, aiming the Earth’s great telescopes with their enormous light-gathering mirrors toward objects that no one knew were there.

Yet for all its potential, Space Telescope is only one part of what NASA calls the “Great Observatories” program.

“We want to put into space observatories for all the wavelengths in the universe,” Fisk said.

Some wavelengths, which can tell much about the dynamics of celestial events, are absorbed by the Earth’s atmosphere. By putting into orbit telescopes that use those wavelengths, scientists will be able to study the universe as it appears through X-rays, gamma rays and ultraviolet and infrared wavelengths.

“The goal by the end of the century is to have all the great observatories operating at the same time,” Fisk said. “This is a unique capability that only the United States has.”

The launching of Space Telescope is to be followed in October, 1989, with a mission that some scientists at JPL were beginning to fear they might not live long enough to see. But unfortunately, they are not out of the woods yet.

Probe Delayed

The Galileo probe to Jupiter was to have been launched in 1986 on a course that would have carried it directly to the distant planet. But the Challenger explosion delayed the launch, and heightened concerns over safety forced NASA to abandon use of the liquid-fueled upper-stage rocket that was to carry it from the shuttle to Jupiter.

After much scrambling and redesigning, JPL scientists came up with a plan that would allow Galileo to be launched from the shuttle with much less powerful--albeit safer--solid-fuel rockets. But those rockets are not potent enough to send it to Jupiter.

So instead Galileo will take an enormous detour. Since it takes far less energy to fall into the sun than fly to the outer planets, Galileo will begin its journey just that way, by firing its rockets to slow its orbit, thus falling toward the sun. But on the way it will encounter Venus, and it will use that planet’s gravity to slingshot itself back out toward the Earth, picking up speed in the process. Two close flybys of the Earth will give it more momentum, ultimately hurling the probe toward Jupiter.

“It takes longer, but we will be able to do more science on the way,” said JPL’s John Casani, project manager.

In its long journey Galileo will fly past an asteroid, and it will continue to train its instruments on the solar system, sending back data all along the way.

“It will be a major event every year from 1989 to 1997,” Casani said. The probe should actually reach Jupiter in 1996 if it is launched next year.

However, if the shuttle’s schedule proves too demanding, and Galileo does not make its scheduled launch, it could be put on hold again. NASA is obligated to launch Europe’s Ulysses solar probe in 1990, and if it comes down to a choice between the two, Galileo will go back on the shelf again, Fisk said.

New Look at the Sun

Ulysses is to go into polar orbit about the sun, giving scientists their first look at areas of the sun that cannot be seen from Earth, and NASA is not anxious to make the European Space Agency any unhappier than it already is. Like Galileo, Ulysses was to have been launched in 1986.

Not all of NASA’s space science projects will be aimed at space in the years ahead. Many of them will be aimed back at Earth, using the unique vantage point of orbit to study what humans are doing to the planet. This is one area where expendable rockets will play a crucial role, ushering in a new era of relatively low-cost satellites.

“As we try to understand changes (in such things as the ozone layer), global observations become very important, and you can only do that from space,” said Shelby G. Tilford, director of earth science and applications at NASA headquarters.

Current evidence indicates that a hole in the ozone layer over Antarctica “is expanding rapidly,” Tilford said. Ozone shields the planet from potentially lethal solar radiation, and any significant change could have profound implications.

Satellites that will study the Earth as a total ecological system are part of a growing movement toward internationalism in space.

“This is one area where we must have international cooperation,” Tilford said.

Such satellites could also tell scientists much about such things as long-term changes in weather patterns.

Tilford said satellites can “actually measure ocean height from one side of the Atlantic to the other” within an accuracy of less than an inch. Scientists covet that kind of accuracy because it tells them when and where depressions occur in the ocean.

“As the ocean moves, there is a depression simply because of the movement,” Tilford said. “This gives us a direct measurement of ocean current and circulation. You can’t do this with a ship because the ship is sitting on the ocean.”

Permanent Space Station

Tilford’s office is developing an ambitious program to monitor the planet with satellites and instruments aboard the permanently manned space station, if and when that becomes a reality, as well as orbiting satellites.

International cooperation also plays an important role in other space science projects planned for the years ahead, including a multination effort to study such things as the effect of the solar wind on the Earth as the planet flys through the “interplanetary medium,” the extremely thin gas and dust that flows throughout the solar system.

The United States, Japan and Europe plan to send up six satellites over the next few years to study such things as what happens when the solar wind hits the magnetic field surrounding the Earth.

“The Soviets are very hot for this also,” said Stanley Shawhan, director of the space physics division at NASA headquarters. Shawhan said the Soviets are expected to put up five more satellites as part of the same program.

All the satellites will provide data that will be available to scientists all over the world, he added.

That will come some time after 1989, the year that NASA hopes to lay claim once again to its role of pre-eminence in space science. Yet the real scene stealer of the year will most likely be an artifact from the agency’s golden age of planetary missions.

The Voyager spacecraft, launched in 1977 but still in good health, was initially to have visited two planets, but it is now heading for its fourth, and possibly most spectacular, encounter.

Images Beamed Back

Nearly 15 months before it is to get there, Voyager is already returning images of Neptune that are about as good as those provided by the largest telescopes on Earth. But those images, showing a dim, fuzzy ball, tell little about a planet in the dark outback of the solar system, spinning through space more than 30 times farther from the Earth than the sun.

Voyager will take its final bows when it sweeps past Neptune’s major moon, Triton, a satellite so large that it could be as big as a planet. No one knows for sure just how big it is.

What mysteries will Voyager solve when it whips past Neptune and Triton? Caltech physicist Ed Stone, Voyager’s chief scientist, believes that the images Voyager sends back from its final encore may be a fitting end to a mission that may not be matched for many decades.

It is possible, Stone muses, that Triton may even have lakes of liquid nitrogen.

Photos of mountain lakes on a moon so far away could, indeed, tell the world that NASA is back.

MAJOR MISSIONS

If the space shuttle is back in operation by early September, the National Aeronautics and Space Administration expects to have a wide range of science missions next year. Although specific launch dates are subject to change, depending on the reliability of the shuttle, here are some of the major events expected by NASA in 1989.

COSMIC BACKGROUND EXPLORER: A satellite that will study radiation left over from the beginning of the universe is to be launched with an expendable rocket in February. MAGELLAN VENUS RADAR MAPPER: NASA’s first planetary probe to be launched in a decade is scheduled for an April launch from the shuttle. If the probe, managed by the Jet Propulsion Laboratory, does not go in April it will be delayed 20 months. HUBBLE SPACE TELESCOPE: After a delay of more than two years, costing hundreds of millions of dollars, the first of a series of major orbiting telescopes is to be launched in June. VOYAGER II: The Voyager spacecraft, launched more than a decade ago, will arrive at Neptune Aug. 25, 1989. Voyager has already visited three other planets, and Neptune is the final encounter on its long journey. GALILEO: It will have to detour by way of Venus to get there, but the Galileo spacecraft, which was to have been launched toward Jupiter two years ago, is scheduled for an October launch from the shuttle. ASTRO 1: An orbiting observatory designed to study the brightest supernova seen in 400 years is to fly aboard the shuttle in November, 1989.