Are there giant caves on Mars? It's a deep subject 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. Their discoverers call them the seven

sisters, black dots on the surface of the red planet that appear to be either deep

pits or perhaps windows on huge lava tubes running under the surface.

Either way, they have once again demonstrated that Mars continues to spring exciting surprises on us.

We'll talk with three of the United States Geological Survey scientists who found and

confirm these holes and are now trying to figure out what they represent.

Later today, Bruce Betts turns the and are now trying to figure out what they represent.

Later today, Bruce Betts turns the tables on you.

You're used to him showing us what's up.

This time, he wants you to show him a specific bit of the night sky and your photo might win you a

prize. That's along with our usual space trivia contest and Emily Lochawala

will be along shortly with a Q&A classic. Things are looking up, if you'll

pardon the expression, on both Space Shuttle Atlantis and the International Space Station.

As we prepared this week's show, NASA had cleared the shuttle for reentry.

A space walking astronaut stapled that troublesome thermal protection system blanket back in place,

and last we checked all the critical computer systems on the ISS

were once again working and talking with each other.

Several of them failed at the same time last week, causing mission controllers considerable concern.

Trouble Shooting continues.

Many of you will remember Mike Brown, the intrepid discoverer of distant coiper belt objects.

Mike Brown and Caltech graduate assistant Emily Schaller

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