The day America's space dream almost died: Son of hero teacher who died alongside six other astronauts leads families in marking the 30th anniversary of the Challenger explosion

One of the defining moments of Ronald Reagan's presidency was when he addressed the nation after the Challenger disaster, postponing the State of the Union address he was set to give that night.

Instead, he paid tribute to the seven heroes, calling the explosion 'a national loss'.

Knowing that Americans young and old watched the failed launch, Reagan took part of his speech to directly address the nation's children.

'I know it's hard to understand but sometimes painful things like this happen.

'It's part of the process of exploration and discovery. It's all part of taking a chance and expanding man's horizons.

'The future doesn't belong to the fainthearted, it belongs to the brave. The challenger crew was pulling us into the future and we will continue to follow them,' Reagan said.

After the disaster, then-President Ronald Reagan addressed the nation from the White House (pictured above)

He then went on to say that the disaster would not bring an end to space exploration.

'Nothing ends here. Our hopes and our journeys continue.'

Reagan finished his moving speech by drawing a comparison to the crew, and the English explorer Sir Francis Drake, who died at sea, mapping the world.

'Today we can say of the Challenger crew, their dedication was, like Drake's, complete

'The crew of the space shuttle Challenger honored us with the manner in which they lived their lives

'We will never forget them, nor the last time we saw them - this morning - as they prepared for their journey and waived goodbye, and slipped the surly bonds of Earth to touch the face of God.'

Three decades: Thirty years after high school teacher Christa McAuliffe (pictured in 1985) died in the Challenger explosion, several of her former students have gone on to teach themselves 

Thirty years after the Concord High School class of '86 watched social studies teacher Christa McAuliffe and six astronauts perish when the space shuttle Challenger exploded on live TV, a number of them have gone into teaching — and some wonder if, indirectly, the tragedy affected them enough that they wanted to make a difference, as she did.

One of them, Tammy Hickey, didn't like social studies at all, but she enjoyed McAuliffe's law class.

McAuliffe took Hickey and fellow students to courtrooms and conducted mock trials in class. Hickey remembers how personable she was, and how she shared her enthusiasm and experiences when she was in the running to be the first teacher in space.

Hickey, now a junior high physical education teacher in Bradenton, Florida, just knew McAuliffe would be picked from more than 11,000 applicants.

'As a teacher now, I know that I want to show respect and show my students that I care,' Hickey says. 'I can say to emulate how she was, would be a service to these kids for sure.'

Hickey joins a number of members of the class of '86 in Concord who became teachers and guidance counselors in the 30 years since they and other students of all ages nationwide watched with disbelief and horror as the shuttle broke apart 73 seconds after liftoff on January 28, 1986, becoming a generational touchstone.

'I try to be very mindful,' says Joanne Walton, who teaches grades four through six in Fairfax, Virginia. She says she sometimes goes through a 'What would Christa do?' mantra in her teaching.

'She knew that teaching was way more than just imparting information and that it was really important to know students,' Walton says.

Holly Merrow, a math teacher for students in fifth through eighth grades in Camden, Maine, had McAuliffe for American Women in History, a class that McAuliffe created and is still taught at Concord High. She worries people will forget her and her motto: 'I touch the future. I teach.'

'I hear people use it, and I wonder if they know that it came from her,' she says.

Members of the class of '86 have petitioned the Obama administration to have a national holiday named for McAuliffe and the Challenger crew, 'to honor Christa and the other astronauts for their ultimate sacrifice.' The hope was to reach 100,000 signatures by Friday, but it has fewer than 200 so far.

Concord, a city of about 42,000, built and named a planetarium for McAuliffe, 37 when she died, then later changed it to the McAuliffe-Shepard Discovery Center, recognizing native son Alan Shepard, the first American in space. Just a few years ago, it named an elementary school for her.

The city has been low-key on marking Challenger anniversaries as her family stayed in Concord and her young children, Scott and Caroline, grew up. Today, both are educators with children of their own. Caroline declined to be interviewed, and Scott did not respond to an email.

Flying: McAuliffe received a preview of microgravity during a special flight aboard NASA's KC-135 'zero gravity' aircraft

'The passage of 30 years since the Challenger accident is not of great personal significance to our family,' their father and Christa's widower, Steven McAuliffe, said in a statement. 'For us, Challenger will always be an event that occurred just recently. Our thoughts and memories of Christa will always be fresh and comforting.'

McAuliffe, a federal judge, added, 'We are happy to know that Christa's goals have been largely accomplished in that she has inspired generations of classroom teachers and students, and has focused public attention on the critical importance of teachers to our nation's well-being.'

Steven and Scott McAuliffe are expected to attend a ceremony Thursday at the Kennedy Space Center Visitor Complex.

Also Thursday, students at Concord High will hold a moment of silence, writing about their dreams as part of a 'Reach for the Stars' assignment and listening to discussions about McAuliffe. They are gathering old yearbook photos and combing through the planetarium archives to put together a permanent display.

Scott Reynolds, a 1987 alumnus who teaches science at the elite St. Paul's School in Concord, conducts a field trip to a local cemetery with his students for one course. The students, from all over the world, get demographic data from the gravesites and make a spreadsheet linking people's deaths to wars and diseases.

When they're done, they drive by Christa McAuliffe's gravestone, and he asks if they know who she was.

'There's always one kid who knows,' he says. 'I can't say I'm depressed. It's 30 years. It's completely understandable that they don't remember this. I'm more enlightened by the fact that there's always somebody who knows who she was.'

Hometown hero: Both of McAuliffe's children have gone on to become teachers as well. The mother and her two kids pictured above during a 1985 parade through Concord, New Hampshire