Like an unruly student, a cold front with threatening thunderstorms delayed the scheduled Sunday morning shuttle liftoff of teacher Sharon Christa Corrigan McAuliffe, who is poised to become what she calls the first "ordinary person" in space.

She and six other crew members are now scheduled for launch at 9:37 a.m. EST Monday from Kennedy Space Center aboard the shuttle Challenger, with McAuliffe's son's stuffed frog, named Fleegle, along as mascot.

McAuliffe, 37, a social studies teacher from Concord, N.H., plans to teach the first classes from orbit to millions of school children.

McAuliffe's adventure begins an era for NASA in which the macho mystique of "the right stuff" will be replaced at least in part with an appeal for everybody's "stuff."

She is first shuttle passenger sought by NASA under its "private citizen" designation. Other nonastronaut passengers have included Sen. Jake Garn (R-Utah), Rep. Bill Nelson (D-Fla.), an Arab prince and German and Mexican engineers.

McAuliffe is to be followed into space by several other citizen-passengers, or "guestronauts," selected by NASA. The next will be a journalist and after that, poets, blue-collar workers, musicians and others will be invited to apply.

Her presence on the mission has achieved at least part of the effect sought by the space agency in boosting public interest, particularly in schools, in the delay-plagued shuttle program.

On Friday, Ron Epps, a senior crew trainer for NASA, compared the globe of the Earth depicted on this mission's official badges to "an apple for the teacher."

After 400 hours of training, including bouncing around in the KC135 training plane sometimes called the "vomit comet," which briefly approximates the sensation of weightlessness, McAuliffe exhibited "no unique problems," he said.

About 850 journalists, nearly twice the average for recent launches, have applied for credentials to cover her flight, officials said. Many are from New England and have never covered a launch.

Thousands of visitors, including 66 busloads of teachers and students, and dozens of public officials and other dignitaries, are expected to be on hand for liftoff, which can occur anytime within three hours beginning at 9:36 a.m.

Vice President Bush, who announced McAuliffe's selection last July from among 11,000 applicants, has said he will attend. So will McAuliffe's husband Steven, an attorney; her son Scott, 9, and daughter Caroline, 5.

Scott McAuliffe, who donated Fleegle from his extensive frog collection to serve as Challenger's mascot, arrived Thursday with 17 classmates from Kimball Elementary School in Concord. His space center tour included a look at the shuttle that will carry his mother on her 2-million-mile journey.

Like other tourists at Spaceport USA here, the class saw movies about the space program, spacecraft models in the "rocket garden" and such exhibits as "The Uses of Velcro in Space."

On the fourth day of the planned six-day mission, McAuliffe is to deliver two lessons from space, via satellite, to classrooms across the country. The lessons will be carried by the Public Broadcasting Service, which has asked its 300 U.S. affiliates to interrupt regular programming for the two half-hour segments.

The unprecedented space classes will permit McAuliffe's students at Concord High School to ask her questions.

During her career, the ebullient teacher has specialized in teaching the role of the unsung common citizen in history. She said one of her goals in applying for the flight was to show that "ordinary people can make a contribution, too."

Barbara Morgan, selected as McAuliffe's alternate, will introduce McAuliffe's lessons, and her students at an elementary school in McCall, Idaho, also will beam questions to McAuliffe.

As many as 25 million students from kindergarten through high school, from Florida to Alaska, might watch the live broadcasts, officials said. About 2.5 million students are expected to see McAuliffe's broadcasts, as well as other shuttle programming, through satellite transmissions to receiving discs at their schools.

McAuliffe, who taught in Prince George's County, Md., schools between 1971 and 1978, will describe life in orbit in the first lesson, "The Ultimate Field Trip." In the second, she will explain why Americans are exploring space.

The mission's other goals, largely upstaged, include deployment of a science probe to study Halley's Comet and launch of a satellite designed to improve communication between ground controllers and future shuttle crews.

The crew is commanded by retired Air Force major Francis R. (Dick) Scobee, with Navy Cmdr. Michael J. Smith as pilot. Mission specialists are Judith A. Resnik, Ronald E. McNair and Air Force Lt. Col. Ellison S. Onizuka. Hughes Aircraft Co. electrical engineer Greg Jarvis is payload specialist.