Starting the fourth with a bang, this week on planetary radio. I'm Mad Kaplan.

Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier.

I'm Matt Kaplan.

Here is the sound of a thousand or so people

celebrating what may be the strangest climax of a space mission in history.

Crash, all right. history. What's? What's? Did you hear Bill Nye, the science guy, yell with glee, it crashed?

By doing so, deep impact, did exactly what it was supposed to do.

But no one suspected the spacecraft's violent end would be so

spectacular. It happened right on time at 1052 p.m. Pacific time, July 3rd 2005.

The huge crowd gathered at the Howe Performing Arts Center in Southern California can perhaps

be forgiven if they celebrated American Independence Day an hour early.

They gathered that evening to hear a series of speakers and to follow the live action a few miles

away at the Jet Propulsion Lab.

That's where an anxious group of engineers and scientists were waiting for the big moment

when the aptly named impactor portion of the two-part probe would hit the tip of Comet Temple

1 at nearly 23,000 miles per hour.

The other part of the spacecraft, joined by scores of telescopes back here on Earth and in Earth

orbit, would watch for this minor Big Bang, revealing for the first time just what's inside these

dirty snowballs that have fascinated humankind for our entire history.

Bill Smyth is one of those deep impact project scientists.

He somehow tore himself away from JPL to join our comet-bashing party up the road.

We started building his, I started building this thing about five years ago and before that a team of people the science team had proposed the mission once that got and turned down that took them a couple of years.

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