CONCORD, N.H. -- Carol Brown will always remember the agonizing moment on Jan. 28, 1986, when she stood near the launching area at Cape Canaveral and watched her friend, Christa McAuliffe, die with six other crew members in the explosion of space shuttle Challenger.

"It was probably the hardest thing I've ever had to go through because it was so sudden, such a complete reversal," said Brown, children's librarian at the Concord Public Library. "It was all one way one minute and incomprehensible the next."

The death of McAuliffe, a popular teacher at Concord High School, remains a tender subject in this city of 38,000.

"I think it's still something we talk about in a very guarded way," said Clinton Cogswell, a Concord elementary-school principal who also witnessed the tragedy firsthand at Cape Canaveral.

Kerry Clock, an elementary-school teacher, said that, while "there's still a sense of sorrow" in the community, it could be eased with the opening here of a planetarium dedicated to McAuliffe and her ideals.

The $3 million pyramid-shaped facility, built with $2.5 million in state funds and $500,000 in corporate donations, is to open formally June 21 and has hosted school groups since late March.

The planetarium was built according to the recommendations of a state commission appointed in 1986 by then-Gov. John H. Sununu (R) to select a memorial for McAuliffe.

Although the city has taken only a little role in the project, Concord residents have responded enthusiastically to the planetarium, which they say captures the spirit of McAuliffe, who is buried in a cemetery overlooking the new building.

"Clearly, it's not simply a statue or a monument . . . . This is really dedicated to children and education -- what she cared about," City Manager James C. Smith said.

McAuliffe's husband, Steve, was among dignitaries who viewed one of the planetarium's dazzling multimedia shows and told an Associated Press reporter, "I know Christa would be delighted." He said the array of shows "graphically demonstrates the beauty of science, the beauty of math."

Former friends and colleagues of McAuliffe, who taught social studies, share her husband's enthusiasm for the project. "It's like a living memorial" to McAuliffe, said Daniel Richardson, a Spanish teacher at Concord, the city's only high school.

The heart of the planetarium production is a DIGISTAR projection system manufactured by Evans and Sutherland Corp., of Salt Lake City. The system involves projecting computer-designed graphics through a fisheye lens onto the planetarium's 40-foot dome. Looking up, the audience is surrounded by celestial objects, which cover the dome.

Traditionally, planetariums have used "mechanical" projection, which involves shining a high-intensity lamp through a ball-shaped collection of metal plates that project the light through lenses onto a dome.

Planetarium Director Clinton W. Hatchett said the mechanical system can offer only a fixed-star field. But with the computer-driven system, used in about 12 other planetariums, viewers can be taken on journeys into distant space, touring other planets, stars and galaxies. With help from about 80 special-effects projectors, the planetarium can simulate everything from exploding stars to Sesame Street characters.

In a recent demonstration, viewers watched a lunar landing from the moon, rotating galaxies, a simulated portrayal of the Hubble Space Telescope and a hookup between an orbiting space station and shuttle. The show was so realistic that it induced the dizzying sensations of floating or hurtling through space.

By late summer, organizers hope to have installed an additional computer system that will enable the 92 audience members to select a destination in space by "voting" on electronic boxes at their seats. The planetarium also may be used eventually for such non-spatial journeys as travels through the human body.

"We're trying to excite kids about what's out there in the universe," Hatchett said.

State Sen. Roger Heath, a member of Sununu's commission, said he thinks of the planetarium as "the classroom of the next century."

Concord High Principal Charles F. Foley said that, because of lingering grief and a desire to respect the McAuliffe family's privacy, the community has been largely quiet about the tragedy. Until now, he said, planning a city memorial would have been premature.

The state-funded planetarium, he said, "serves us very well."

Smith said many Concord residents are optimistic that, with the formal opening of the planetarium, "we can have the hoped-for celebration, the good feeling everyone was looking forward to and expecting when Christa returned."