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Planetary RadioOctober 18, 2016

Charley Kohlhase and the Greatest Voyage

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On This Episode
Charley Kohlhase and Richard Spehalski with Cassini and the DVD
Charley Kohlhase

Engineer, Artist, Cassini Mission Designer

How did the Voyager spacecraft manage to weave their magnificent way through the outer planets of our solar system? Mission Design Manager Charley Kohlhase led the team that crunched the numbers to select the best possible trajectory from 10,000 candidates. The results have been astounding. Emily Lakdawalla prepares us for the arrival of Europe’s Exomars orbiter and Schiaparelli lander. Bill Nye says millennials and President Obama share excitement about humans to Mars. Win a copy of “Star Trek: The Official Guide to the Universe” in the What’s Up segment.

Charley Kohlhase

Charley Kohlhase

Charley Kohlhase
James Blinn (l.) and a young Charley Kohlhase (r.) working at JPL on pioneering computer animations of the Voyager flybys.
High-resolution global view of Jupiter from Voyager 1

NASA / JPL / Björn Jónsson

High-resolution global view of Jupiter from Voyager 1
A 14-frame mosaic of Jupiter from Voyager 1. Most of the data for this mosaic was captured in a 3-by-3 mosaic at around 8:45 on February 27, 1979, but gaps were filled with data taken an hour before and an hour later.
Saturn and its rings from Voyager 1


Saturn and its rings from Voyager 1
Voyager 1 looked back at Saturn on Nov. 16, 1980, four days after the spacecraft flew past the planet, to observe the appearance of Saturn and its rings from this unique perspective. A few of the spokelike ring features discovered by Voyager appear in the rings as bright patches in this image, taken at a distance of 5.3 million kilometers (3.3 million miles) from the planet. Saturn's shadow falls upon the rings, and the bright Saturn crescent is seen through all but the densest portion of the rings.
Uranus' crescent, February 1, 1986

NASA / JPL / Emily Lakdawalla

Uranus' crescent, February 1, 1986
A week after its flyby, Voyager 2 still had a high-resolution view of Uranus' receding crescent using its narrow-angle camera.
Neptune from Voyager 2

NASA / JPL-Caltech / Justin Cowart

Neptune from Voyager 2
This Voyager 2 Narrow Angle Camera image of Neptune was taken on August 20, 1989 as the spacecraft approached the planet for a flyby on August 25. The Great Dark Spot, flanked by cirrus clouds, is at center. A smaller dark storm, Dark Spot Jr., is rotating into view at bottom left. Additionally, a patch of white cirrus clouds to its north, named "Scooter" for its rapid motion relative to other features, is visible. This image was constructed using orange, green and synthetic violet (50/50 blend of green filter and UV filter images) taken between 626 and 643 UT.
The Pale Blue Dot of Earth


The Pale Blue Dot of Earth
This image of Earth is one of 60 frames taken by the Voyager 1 spacecraft on February 14, 1990 from a distance of more than 6 billion kilometers (4 billion miles) and about 32 degrees above the ecliptic plane. In the image the Earth is a mere point of light, a crescent only 0.12 pixel in size. Our planet was caught in the center of one of the scattered light rays resulting from taking the image so close to the Sun. This image is part of Voyager 1's final photographic assignment which captured family portraits of the Sun and planets.

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Trivia Contest

This week's prizes are Andrew Fazekas’ book, “Star Trek, The Official Guide to Our Universe,” a Planetary Society rubber asteroid, and a 200-point astronomy account.

This week's question:

In what region of Mars will the European Space Agency’s Schiaparelli land?

To submit your answer:

Complete the contest entry form at or write to us at [email protected] no later than Tuesday, October 25th at 8am Pacific Time. Be sure to include your name and mailing address.

Last week's question:

What moon in our solar system has the longest orbital period around its parent planet?


The answer will be revealed next week.

Question from the week before:

What are the names of the two asteroids Rosetta studied, and the name of the comet it orbited and was just set down on?


The asteroids studied by the Rosetta spacecraft were 21 Lutetia and 2867 Steins, while the comet it orbited was 67P/Churyumov Gerasimenko.

Listen more: history, Space Policy, mission status, Planetary Radio, ExoMars TGO, Mars, Bill Nye

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