January 28, 1986 is a moment seared into our collective memory.

Just 73 seconds after it lifted off, the space shuttle challenger exploded from a leak that ignited the main liquid fuel tank.

All seven astronauts aboard died, including Krista McCullough, the first teacher to fly in space.

She's one of the reasons why so many people were watching that day

and never forgot it. Our resident space expert, Miles O'Brien, was covering the launch and has

his own personal connections. So settle in while we talk about how that tragedy 40 years ago

changed the shuttle program and NASA.

Miles O'Brien, always great to speak with you.

Likewise, Jeff.

The Challenger launch, 1986,

viewed by schoolchildren all across the country.

Interestingly enough, the space shuttle program had already been underway for several years.

So why was this particular launch?

Why did it capture the public's imagination in a way that previous launches hadn't? It was all about the teacher, Jeff, Krista McColliffe, elementary school teacher from Concord, New Hampshire,

who had participated in a nationwide contest to become the first teacher in space.

She was a fabulous, interesting character and won the rights to fly on the shuttle as the shuttle

program turned toward allowing civilians to fly in space.

They had previously flown then Congressman Bill Nelson, later senator, later administrator of NASA,

and Utah Senator Jake Garn.

And they were leaning toward trying to show the world that the space shuttle system was routine and could

get people to space, everyday people to space in a relatively inexpensive way.

And Krista McColliffe was supposed to be the first of several civilians that would fly.

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