Space Shuttle Flight Director Paul Hill, this week on planetary radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier.

I'm Matt Kaplan.

Everything looks a-okay for Space Shuttle Discovery as we put the finishing touches on this week's program.

Early on Sunday morning, NASA gave the go for a Wednesday July 13 launch.

The world will be watching this return to flight after a two and a half year hiatus.

The man in charge of SDS 114 will give us a quick update on flight status and review the many measures

NASA has taken since the Columbia accident.

Then we'll talk about return to flight and what comes after the shuttle with astronaut and scientist Owen

Gariot.

Stick around for Bruce Betts and special guest Bill Nye the Science Guy on a festive edition

of What's Up. And Emily is back with Q&A, right after just a couple of news notes.

Got SETI?

You millions of SETI at home users should know there has been an exciting development.

No, we haven't found ET yet, but if your computer comes up with that jackpot signal, we'll all know

about it much sooner.

Get the details at planetary.org where you can also see new and achingly beautiful

images from Cassini at Saturn.

Okay, here's Emily and a thousand billion friends. I'll be right back.

Hi, I'm Emily Loch Dowala with questions and answers.

A listener asked, how many comets are there?

Once in a while, the news headlines are full of stories about a comet that is visible

from the Earth with the naked eye.

...