The debate over the California desert began yesterday on Capitol Hill, complete with celebrities on camera and rhetoric as blistering as the Death Valley sun.

The occasion was the first Senate hearing on legislation to set aside more than 8 million acres of southeastern California as national parkland or wilderness. Environmentalists contend the action is needed to protect fragile desert lands; opponents view it as an attempt to lock up millions of dollars of minerals, grazing land and recreational terrain.

In other words, it's a textbook confrontation between conservationists and developers -- and both sides came out swinging.

In a morning news conference, the bill's author, Sen. Alan Cranston (D-Calif.), called Interior Secretary Donald Hodel an "environment-buster" who has allowed prospectors and dirt bikers to despoil the desert.

"From the mountains to the deserts, from the oceans to the ozone, Hodel has aided and abetted a creeping destruction, degradation and devastation of our environment," Cranston said. "Hodel almost makes one yearn for the 'good old days' of {former interior secretary} James Watt."

In Cranston's corner: screen stars Shelley Duvall and Morgan Fairchild, Lt. Gov. Leo McCarthy, a fellow Democrat, and representatives of most major environmental organizations.

Interior officials responded at an afternoon hearing of the Senate Energy and Natural Resources subcommittee on public lands, accusing Cranston and his allies of breaking faith with Californians and seeking to rekindle a decade-old battle that culminated in a comprehensive management plan for the desert.

"We believe this legislation would have a great negative impact on this 25 million-acre area, which comprises more than one-quarter of the state of California," said J. Steven Griles, assistant secretary for land and minerals management.

In Griles' corner: the Reagan administration, the administration of Republican Gov. George Deukmejian, and the California Desert Coalition, recently formed to represent the miners, ranchers, rockhounds, off-road vehicle owners and other groups who fear loss of access to the desert.

At stake is a piece of California nearly as large as the state of Kentucky, stretching from from Death Valley National Monument to the Mexican border. Nearly half of the land -- more than 12 million acres -- is administered by the Interior Department's Bureau of Land Management under the California Desert Conservation Plan.

Congress set up the plan in 1976 after conservationists complained that developers and recreationists were running roughshod over an ecosystem so fragile that tank tracks from military maneuvers are still visible 40 years after they were made.

Many of the plan's original proponents have become increasingly disenchanted with the program, saying it has been weakened by pro-development amendments, lax enforcement and a strong pro-industry bias under the Reagan administration.

Cranston's bill would take nearly 4 million acres from the bureau and transfer them to the National Park Service, creating three new national parks, and designate another 4.5 million acres in more than 80 areas as wilderness, off limits to mineral exploration and motorized traffic.

According to Cranston, the park and wilderness boundaries were drawn to exclude existing mines and popular off-road vehicle areas, and would leave more than 30,000 miles of paved and dirt roads open to motorists.

Interior officials contend that the bill would close off "thousands of miles" of access routes, to the detriment of residents as well as recreationists. "Simply stated, no one uses the desert without the use of motorized vehicles," Griles said.

Of more concern to the officials, however, is the prospect of closing off part of the desert to mineral exploration. Griles yesterday told the panel that the California desert is the nation's foremost source of rare-earth elements, which have drawn interest because of their potential use in high-temperature superconductors.

"If we cut off access to the sources of rare earths, we are putting these superconductivity advances in jeopardy," he said.

Andrew Grosz, a rare-earth specialist with the U.S. Geological Survey, said in an interview yesterday that one California desert mine produces most of the nation's light rare-earth elements. The heavier elements most commonly used in superconductor experiments, such as yttrium, are imported from Australia, he said.