About eight months from now, according to current Pentagon plans, a B52 bomber flying over the Beaufort Sea along Canada's Arctic coast will launch a cruise missile southward into the frigid air, then wheel away.

If all goes according to plan, the unarmed flying bomb will drop low, then navigate a meandering course over snowcovered conifer forests, muskegs and isolated Indian settlements east of the Mackenzie River in Canada's remote Northwest Territories. Reaching the Primrose military test range straddling Alberta and Saskatchewan provinces at Cold Lake, after a 1,370-mile flight, the 20-foot-long Boeing missile will pop a parachute and come to rest in front of waiting technicians.

The United States wants about a dozen such flights. They are considered crucial to checking out the missile's ability to carry nuclear warheads across similar monotonous terrain of the northern Russian plain to Moscow and other strategic Soviet targets.

Outside of the Soviet Union itself, only the subarctic Mackenzie lowland has enough featureless terrain to adequately challenge the complex cruise navigation system, which steers its way to a designated target by using onboard radar and altimeters to compare ground contours with electronic maps stored aboard. The flight path is adjusted if they do not agree.

The United States has not yet asked for permission to stage the tests, which it would like to conduct next winter. But the prospect of the flights has stirred Canadians as few other arms issues in recent years. The controversy has put unexpected pressure on the Liberal government of Prime Minister Pierre Elliott Trudeau, ruffled cross-border relations anew and helped fuel a debate here about the Reagan administration's military policies, the value of the NATO alliance and the global disarmament movement.

The issue resembles the European controversy over NATO's 1979 decision to begin placing 572 new Pershing II and cruise missiles on the continent this year to answer a Soviet buildup of SS20 missiles targeted on Western Europe.

It reflects an underlying aspect of life here that frequently is overlooked in the United States--Canada's European orientation. Like citizens of nonnuclear West European powers, Canadians virtually across the political spectrum increasingly are concerned over the lack of progress in U.S.-Soviet negotiations on the Euromissile question.

Vice President Bush led a U.S. delegation here last week as part of the administration's effort to assure its NATO partners that Reagan sincerely wants mutual arms reductions. At a state dinner completing the visit Trudeau said, as he has before: "Our people want more evidence of flexibility" from Washington and Moscow on the talks. At the same time, however, he said, "We'd be pretty poor alliance partners if we said no" to a U.S. request for permission to use Canadian air space for the cruise tests.

But the anticruise movement remains undeterred.

"My personal hope is that we use this as a symbolic issue to wind down the arms race," said Dr. Pauline Jewett, a New Democratic Party member of Parliament from British Columbia. She is spokeswoman on the cruise issue for the 32 NDP members of the 282-seat House of Commons. The socialist NDP is unanimously opposed to the tests under any circumstances.

"I view the cruise as destabilizing," she said. "It would be very hard to verify, and people feel this in their bones."

Sentiment for a nuclear weapons freeze has risen markedly since mid-1981 throughout the country, Canadians say. The national press has given detailed coverage of the arms reduction talks in Europe and closely followed the Reagan administration's anti-Soviet declarations.

Influential columnists, scientists and former government officials are emphatically calling for greater U.S. efforts at the conference table. Frequently these calls are tied to comments on the possible cruise missile tests.

Last month, for example, George Ignatieff, a former U.N. ambassador and NATO representative, told a Toronto peace gathering that "helping in the development of cruise technology won't make us more secure, it will make us more susceptible to an attack from the Soviets . . . . The testing would increase Canada's commitment to continental defense at a time when we are supposed to be doing less."

Meanwhile, a grass-roots organization called Operation Dismantle last year spearheaded a drive to get a general disarmament referendum on municipal election ballots in November. After a series of court fights to breach Canada's stiff rules that virtually rule out a U.S.-style referendum petition drive, a question calling for general disarmament was included on ballots in 123 towns and cities. Almost a million Canadians voted, and 76.5 percent voted in favor of the proposal.

Gallup polls over the past five years show that Canadians support the idea of a U.N. disarmament referendum by about 3 to 1. The local referendum drive, similar to the U.S. freeze movement's referendum drive last year, will continue.

T. James Stark, who founded Operation Dismantle six years ago and now dreams of a global referendum, says Reagan is the reason for rising Canadian concern. "In a way, he is the godfather of the movement," Stark said. "His talk of limited nuclear war has propelled this forward."

Ottawa and Washington last month signed a framework agreement pledging negotiations whenever the United States actually requests the cruise tests. The agreement thus allows Trudeau some breathing room while giving Washington a measure of reassurance that his government's intentions are positive on the question.

Canadians continue to hope that some kind of breakthrough will occur in the Euromissile talks and that the Soviet Union and the United States will reduce the number of theater weapons poised over Western Europe.

But even if this came about, the United States still would want to test the cruise missile guidance system over Canadian terrain. While negotiators conceivably could agree not to deploy any of the ground-launched cruise missiles planned for Western Europe, the United States still plans to develop air-launched and submarine-launched versions. The guidance systems are the same for all three versions, so the tests still would be needed.