Planetary Radio • Apr 21, 2015

Saving the Planet at the Planetary Defense Conference

Please accept marketing-cookies to listen to this podcast.

Download MP3

On This Episode

20150421 william ailor thumbnail

William Ailor

Distinguished Engineer for The Aerospace Corporation

20150421 Fabrizio Bernardi thumbnail

Fabrizio Bernardi

Chief Executive Officer for SpaceDyS

Paul chodas portrait

Paul Chodas

Manager, NASA NEO Program Office for Jet Propulsion Laboratory

20180710 Lindleyat Helm

Lindley Johnson

Planetary Defense Officer for NASA

20190926 Detlef Koschny large

Detlef Koschny

Planetary Scientist for ESA

20131231 amy mainzer

Amy Mainzer

Professor in the Lunar and Planetary Lab at the University of Arizona, Principal Investigator for the NEOWISE mission, and leads the NEO Surveyor project

Planetary Radio Live was the only public event at the just-completed Planetary Defense Conference in Italy. Join us for excerpts from an all-star celebration of worldwide efforts to find, track, characterize and eventually deflect killer Near-Earth Objects. Our guests are William Ailor, Fabrizio Bernardi, Paul Chodas, Lindley Johnson, Detlef Koschny and Amy Mainzer. Bruce Betts was on hand for an on stage What’s Up segment and award of the latest round of Shoemaker NEO grants.

Planetary Radio Live at the Planetary Defense Conference
Planetary Radio Live at the Planetary Defense Conference The all-star panel on stage at the Italian Space Agency for Planetary Radio Live at the Planetary Defense Conference.Image: Erin Greeson

Related Links:

This week's prize is Jim Bell’s excellent book, "The Interstellar Age: Inside the Forty-Year Voyager Mission," signed by the author.

This week's question:

As of April 11, 2015, about how many near-Earth comets are there known to be?

To submit your answer:

Complete the contest entry form at or write to us at [email protected] no later than Tuesday, April 28th at 8am Pacific Time. Be sure to include your name and mailing address.

Last week's question:

What is the orbital period of Neptune’s moon Triton?


The answer will be revealed next week.

Question from the week before:

What are trans-Neptunian objects in a 2:1 orbital relationship with Neptune called? (2 orbits of Neptune, 1 orbit of the body)


Trans-Neptunian objects in a 2:1 relationship with Neptune are called Twotinos.