The European spacecraft Giotto caught the first pictures ever taken of the surface of Halley's comet last night -- with glimpses of what appeared to be hills, valleys and a mountain -- before the craft suddenly was hammered by a "wall of dust" and the historic pictures ended abruptly.

The European Space Agency scientist in charge of the spacecraft's cameras narrated what promised to be the most exciting moment of Halley's return, when Giotto would pass near the surface of the mysterious object that appears in 2,200 years of human legend.

The scientist-narrator in Darmstadt, West Germany, became increasingly excited as the image of the comet's nucleus, about 930 miles from Giotto, filled the viewing screen.

"It's rather like an odd-shaped potato," he recounted. "It's obvious there is structure to the nucleus. It is like mountains or little hills . . . a crater . . . there is an area which is like white snow against surrounding dark dust. It is incredible detail . . . marvelous detail," he said, and suddenly stopped in mid-sentence. "Well, ahhh . . . . "

The signal turned to static and the images disappeared as the 9-foot-tall cylindrical craft was 415 miles from the comet's nucleus. Scientists soon reported that Giotto, which had been sailing through an area relatively free of dust, slammed into a wall of particles as large as sand grains traveling faster than bullets.

The particles shot straight through the one-millimeter-thick shield put up to protect the cameras and other instruments from damage, scientists said.

After a 25-minute blackout, Giotto began transmitting data again, but there were no more pictures, officials said.

"Some equipment is operating. We are receiving some data. We think we have not lost the spacecraft," said ESA's Peter Wenzel.

The scene from West Germany was transmitted by satellite to the United States and other nations. Giotto's photographs were viewed here at the National Aeronautics and Space Administration headquarters. A briefing today should disclose more about the damage and the data.

The sudden encounter with dense dust also was felt by two Soviet Vega spacecraft that flew within about 5,000 miles of the comet's nucleus in the past week. The two craft lost about half their power when comet dust pierced their solar panels.

The Giotto craft, launched by ESA last July, was named after the Italian painter Giotto Bondone, who apparently saw the comet in 1301 and painted an image of it in a chapel in Padua. Yesterday's false-color images transmitted back to Earth were in colors more brilliant than any on an artist's pallet, with the center appearing in an electric red oval, surrounded by light blue, magenta, periwinkle blue and dark blue ovals.

Estimates made from last night's encounter suggest that the comet's nucleus is about 1.8 miles by 4.3 miles.

The most widely accepted theory holds that comets have cores of ice embedded with dust and small rocks, which leave trains of glowing dust and gas thousands of miles long. When a comet nears the sun, its light heats and sizzles off layers of the comet's surface to make the cometary tail.

Comets, scientists believe, constitute small, frozen samples of the soup that made the solar system4.5 billion years ago. Although comets have glided in the space around Earth's sun from the time of the solar system's birth, man still has not discovered some of the simplest facts about their composition and behavior.

The flotilla of spacecraft and instruments recently sent by the Soviets, Europeans, and Japanese are intended to answer some of these questions, such as:

*What were the materials that made up the solar system at its formation, and later made up planets and life itself?

*Will there be much ammonia or methane or other complex molecules in Halley?

*What elements and minerals make up the comet's dust?

Although scientists have guessed and estimated for years about the answers, they now have an opportunity to measure directly the size and chemistry of the hunk of ice and dust that is the nucleus of the comet, as well as its shape and rate of tumbling.