Sharon Christa McAuliffe, a New Hampshire social studies teacher who says she will keep a pioneer's journal in orbit, is to be the first representative of the private citizen in space, Vice President Bush announced yesterday.

McAuliffe, 36, who teaches at Concord High School in New Hampshire and has a special interest in women's studies, was chosen from 10 teacher finalists to board the shuttle Challenger in January.

Barbara R. Morgan, 33, a second grade teacher in McCall, Idaho, was chosen as backup in case McAuliffe cannot go.

Bush, announcing McAuliffe's selection at a White House ceremony in the Roosevelt Room, pronounced her one of America's teachers with "the right stuff." She broke into tears when Bush read her name.

The finalists, chosen from among 11,416 applicants, had been told of the selection on their way into the White House only minutes earlier.

"It's not often that a teacher is at a loss for words," McAuliffe, who goes by Christa, said at the White House ceremony. "I know my students wouldn't think so."

McAuliffe, a teacher for 15 years that included work in Prince George's County schools from 1971 to 1978, wore a red rose pinned to her yellow blazer as she met with reporters on the White House lawn after the ceremony.

She described herself as "an ordinary teacher, but touched by an extraordinary experience . . . It's an unbelievable experience."

In her application, she said her project in orbit would be keeping a journal, "just as the pioneer travelers of the Conestoga-wagon days kept personal journals."

She told reporters that she hopes it will convey "the ordinary person's perspective."

McAuliffe, married to a lawyer and the mother of two children, will work for a year for the National Aeronautics and Space Administration at her normal pay, which she said is slightly more than $20,000 annually.

She and Morgan are to report to Johnson Space Center in Houston in September for 114 hours of training over four months.

McAuliffe said it will be unusual for her to begin a school year outside the classroom, but Bush promised there would be a substitute: Education Secretary William J. Bennett, who has said he wants to try some teaching again, is to stand in for her first class next fall.

McAuliffe called herself a "space participant," not an astronaut.

She is scheduled to make a six-day flight beginning Jan. 22 with five astronauts, including another woman, Judith A. Resnik. For a year afterward, she is to be a public relations worker for the space agency, and a liaison to educators.

Morgan, the runnerup, asked whether she was disappointed, replied: "I think we're all going to get a chance to fly someday."

The other eight finalists have been invited to Cape Canaveral in Florida for the launch.

They also have been asked to work for NASA for the next year in some capacity, although the details are not final, said NASA spokesman Sarah Keegan.

Two area teachers were among the other finalists -- Kathleen Anne Beres, 36, who teaches biology at Baltimore's Kenwood High School, and Judith Marie Garcia, 44, who is to teach French and Spanish at Fairfax County's new Thomas Jefferson High School for Science and Technology in Annandale.

"None of us feel we'd lost or were second best or were slighted," Beres said. "There has to be a bit of disappointment, but it's a new beginning. I look forward to going back to the classroom and telling my students about it."

Garcia, a teacher for 21 years, said she hopes a new vocabulary of space-related expressions will help hold her students' attention "while they're learning to conjugate verbs"-words such as la nave espacial and la navette spatiale -- Spanish and French for "the ship in space."

For now, "I'd like to go to the beach, lie in the sand and listen to the waves," Garcia said.

The 10 teachers, six women and four men, plan to reunite next month to help write lessons for McAuliffe to teach from space, and lessons for her Earth-bound colleagues around the country.

Said McAuliffe at the White House: "When that shuttle goes, there might be one body, but there's going to be 10 souls that I'm taking with me."

A top NASA official said McAuliffe was an early favorite of the 20-member selection panel, whose members ranged from former astronauts to TV stars.

She did well on a series of tests for the would-be astronauts in Houston last month, including a flight in a KC135 training plane that gives its passengers a brief experience of simulated weightlessness.

The official said the judges thought McAuliffe appeared to be a good team player and -- vital to her image-making duties -- stood out as a good communicator.