Ion Engine speed dawn toward asteroid Vesta this week on planetary radio. Planetary Radio. Welcome to Public Radio's Travel Show that takes you to the Final Frontier.

I'm Matt Kaplan of the Planetary Society.

Dawn Mission Chief Engineer Mark Raymond returns with an update on the spacecraft that will

orbit the two largest asteroids in our solar system.

Emily Lochuilohala reports on another impending encounter with a big

space rock in the Planetary Society blog, and Bill Nye, the Planetary Guy, will salute the now fully deployed

Icaros solar sail.

Have you ever wanted to have your very own space shuttle?

Bruce Betts and I will help you get it if you tell us why you need one.

That's later during What's Up.

First up is Emily.

She took time out from her vacation to join me by phone

for a review of recent blog entries.

One of the most significant things that you covered

over the last week was this upcoming

encounter between the European Space Agency's Rosetta and Lutisha.

Yes, Rosetta is I think the spacecraft that must win the award for the longest and most

circuitous cruise to its eventual destination. It arrives at Comatrio

Mogherson-Menko in 2014. On the way it's encountered Earth a couple

times in an asteroid named Stains, and this time it's about to fly past an asteroid named Lutisha.

Lutisha is by far the largest asteroid that has ever been visited by a spacecraft. It's numbered 21 in the asteroid

catalog and that alone tells you that it was discovered pretty early on so it must be

...