It was just as Christa McAuliffe would have wanted.
The Concord High School teacher and her six crewmates on the space shuttle Challenger appear with no special billing in a school lesson on space travel.
It was just as she once taught, that ordinary people make history. Except this time, she was the ordinary person and the history was a disaster 20 years ago Saturday that wounded the school and city so deeply that the slightest touch still can bring tears.
This week, as he has done for 19 previous anniversaries, biology teacher Philip Browne taught his students about space travel, from the Mercury missions to the space station. As McAuliffe did in her social studies classes, Browne kept it simple.
He demonstrated the size of the shuttle's cargo bay with an illustration of it holding a Trailways bus; he showed how the parts of its solid rocket booster were stacked together like round Lego blocks, sealed with huge rubber washers called O-rings.
And he explained what could happen if those O-rings got cold and brittle, as they did on Jan. 28, 1986, allowing flames to escape and hit the shuttle's huge fuel tank.
"A rubber O-ring failed, the flames leaked out, burned through the orange (fuel) tank, exploded the oxygen and hydrogen, and the shuttle never made it into orbit," said Browne, 57, who was one of four other New Hampshire finalists in the national competition that eventually selected McAuliffe to be the first teacher in space.
Around each anniversary, he takes his classes to McAuliffe's grave and the nearby planetarium built in her honor. In class, Browne calmly and expertly explains the science, but in an interview afterward, a single word, a question about the cemetery sojourn, brings him to tears: "Why?"
Taking a deep breath to fight sobs, he responds: "I don't want anybody to forget ... their bravery, their dedication. They were people who loved life. They wanted something better for the world."
The school is exhibiting material from McAuliffe's odyssey and offering students a new documentary about the teacher-astronaut's life. No special ceremonies are planned by the city.
Assistant Principal Bill Haubrich said the anniversary presents an annual dilemma.
"There is a legacy here. How do we promote the legacy, and not promote that particular day that was the most painful day in our school's history?" he said.
McAuliffe's husband, Steven, and children Scott and Caroline disappeared from public view after the explosion. In a rare comment, McAuliffe, now remarried and a federal judge, said he is grateful to the community.
"Our children have been taken in and protected by everyone, and so were allowed to grow up normally and without undue focus or attention, in the best of American small towns," he wrote in an e-mail to The Associated Press. "I suspect there are not many places where that could have happened, and I know Christa would want me to express her appreciation as well for that priceless gift."
Son Scott, 29, is married and pursuing a career in marine resource management, McAuliffe wrote. Daughter Caroline is 26, an educator like her mother.
"They both are healthy, happy, great kids, and first-rate people," their father said.
Twenty years ago, the city buzzed with excitement over Christa McAuliffe, who was 37. Scott's third-grade class even went to Florida for the launch.
Ben Provencal, 28, was one of the third-graders shivering in the VIP bleachers when Challenger exploded 73 seconds after liftoff.
A full-page photo in Newsweek later showed Provencal, looking tiny in his oversized baseball cap, his hands pulled into his sleeves against the cold. His teary eyes stared at white smoke and zigzag rocket contrails the explosion painted on the brilliant, blue sky.
Provencal said he and his classmates understood before their parents that the Challenger had exploded.
"We had been studying the space shuttle at school. We knew every second of that launch sequence and what was supposed to happen," he said.
He remembers the emptiness and the reluctance long afterward for teachers and friends to talk about space travel, especially when Scott was around. Now he focuses on other aspects of the trip, and on McAuliffe's goal.
He does it as "Mr. P.," special education assistant and coach at Concord's Rundlett Middle School.
"I used to say, `I want to be an astronaut too,"' Provencal said, "but now I'm so proud that I teach kids and work with kids and I can follow in the footsteps of people who were as incredible as Christa was."
Former classmate Zach Fried shared binoculars with his dad to gaze at the rising shuttle. He said the tragedy prompted questions about trust.
"I think all of us ended up with perhaps a different take on institutional confidence in what the government and what adults could tell us and promise us at the time," said Fried, 29, a graduate student at the University of Michigan.
Many assumed, he added, "that maybe we'd all be traumatized to a degree, and I think that, happily, that hasn't happened. ... Perhaps it made us into more thoughtful people, more thoughtful citizens."
As McAuliffe prepared for astronaut training, she realized she was caught up in her own lesson plan — that ordinary people make history. In an interview in August 1985, she said her students were part of it, too.
"I might be a name that is chosen to be put in the history book because I'm the first of a program, but what I try to tell my students is that 20 years from now, people are going to be looking back at 1985 and wondering what teenagers were like because they are a big part of the population."
Provencal recognized the connection.
"It's so true," he said. "That's exactly what she did. She made all of us part of history."