How wet was Mars and for how long? This week on planetary radio.

Welcome, I'm Matt Kaplan of the the Planetary Society, with more of the human adventure across our solar

system and beyond.

Brioni Horgan has returned to share news about those long gone days when the red planet looked much more like our own.

How long did the water flow?

Long enough for life to get a toehold?

And when the freeze came, was it forever?

Or were there multiple ice ages,

like those Earth has known?

Also ahead is our weekly visit with the chief scientist.

Dr. Betts and I recorded this week's

what's up early so that I could head out on a brief vacation.

That's why this week's show is a bit abbreviated.

We'll begin with our new tradition.

Here are three stories you can find in the October 18th edition of

The Downlink, the Weekly Digest of Planetary Science and Exploration, edited by our own Jason Davis.

We'll begin with the story that got most of the attention last week.

While they would tell you it's no big deal in practical terms,

the first space walk conducted entirely by women is still a milestone worth noting.

NASA astronauts Christina Cook and Jessica Meyer successfully completed their work outside

the International Space Station right on time.

This was the 421st time humans have gone EVA, beginning with that first stroll in the park

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