Five little helium weather balloons were launched today into the foggy early morning darkness here along the Oregon coast and all they had to do was drift east. Everything and everybody else was ready.

But the balloons went the wrong way, grounding Vera Simons of McLean, her crew of three, and the 8,488 pounds of gear -- including four bottles of French champagne -- they had packed aboard the DaVinci TransAmerica. That's the high-altitude balloon that's been waiting here nearly two months to attempt the first non-stop balloon crossing of the United States.

The 7-Up soft drink company, which is paying for most of the $250,000 effort, had dispatched its director of corporate affairs from St. Louis for today's expected launch. He had said the balloon "can't miss."

Balloon launching experts from Minnesota stayed up all night waiting to pump helium. Tillamook County sheriff's deputies directed traffic in the dank morning.

But the little helium balloons drifted west over the Pacific and the balloon flight, which has provoked court battles between two major television networks and is under investigation by a federal agency, was delayed until Wednesday.

"What we've got is a defect in the wind right around Tillamook," said Rudolf J. Englemann, the balloon flight director.

Weather reports indicated that there was a fair weather pattern moving east, which is precisely what the DaVinci TransAmerica needs for its planned six-day, 2,295-mile flight to Norfolk, Va.

Yet, according to Bob Rice, the Bedford, Mass. meteorologist who is advising the balloonists here by telephone, there was a hole in that weather pattern around Tillamook, where the winds were blowing the wrong way.

In pre-flight preparations on Sunday, Englemann told the meteorologist that in order to lift off today the crew was more than willing to spend a few hours floating over the ocean. "Listen," Englemann had said over the phone, "I'm not scared to go out over the Pacific as long as you tell us how long we'll be there."

But meteorologist Rice said today he couldn't guarantee that the balloon would ever drift back to the continental United States if it were launched this morning.

Since 1775, when a French man named Pilatre de Rozier was burned to death in an ill-designed combination hot air-hydrogen balloon, success in long-distance ballooning has not come easy. Seventeen balloons failed and five pilots died before the first successful crossing of the Atlantic ;ast August. last August. TransAmerica said it was not discouraged by its misfortunes.

Their bad luck began in August when ABC television went to court in New York, filing a suit aimed at stopping the balloonists from granting NBC exclusive rights to cover the flight. The suit was thrown out of court, but Vera Simons, the Northern Virginia balloonist who has been planning the flight since 1971, said the legal tangle "really upset" her and delayed flight preparation.

Two weeks ago, the National Oceanic and Atmospheric Administration (NOAA) withdrew its support from the flight and pulled its instruments off the balloon. The instruments were to be used to measure air pollutants, ozone levels and radiation as the balloon floated over the nation.

NOAA said that the move was made because an agency employe, identified by sources as Englemann, may have used his "position or the influence of his position for his personal gain." NOAA lawyers are investigating the possible illegal conflict of interest.

Englemann, who had stated that he knows of no conflict of interest and who terms the accusations against him "a helluva thing", said today that despite the legal problems and the delays imposed by wayward winds he "remained optimistic."

"The crew is up to snuff," said Englemann, who slept three of the past 48 hours. "We've got a good weather system and I'd be really surprised if we didn't go Wednesday."

Simons, pilot of the plastic translucent balloon that is larger than the Goodyear blimp, didn't attend today's morning press conferences, the first of which was held at 3 a.m.

She was in her hotel nearby at 1:15 a.m. when her husband called the balloon control launching site. He was told the wind was wrong. "Let Vera sleep," balloon control said.