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June 2005

Image Credit: NASA/JPL

This illustration shows you the orbit of Earth and comet Tempel 1, along with their positions when the Deep Impact spacecraft was launched and at the time of the spacecraft's encounter with the comet.

Image Credit: NASA/JPL

Here's a closer view of the trajectory of the spacecraft. As it crosses the orbit of the comet it will actually be moving slower than Tempel 1 and thus it will get 'run over' by the comet. About one day prior to the collision the spacecraft will release the Impactor - which will actually hit the comet - while the main body of the spacecraft will perform a small trajectory correction maneuver that will cause it to pass close to the comet without hitting it. The Impactor will relay pictures and other data right up to the time of impact while the other vehicle will photograph the collision and make other measurements. At the time of the encounter the spacecraft and comet will be approaching each other at a relative velocity of over 6 miles per second. The nucleus of the comet is only a few miles across and thus if the timing of the spacecraft's arrival is off by just a couple of seconds it will miss the comet entirely. Pulling off this mission has been described as attempting to hit a bullet with a bullet while photographing the results from a third bullet.

Image Credit: NASA/ESA/JHU

Telescopes from all over the Earth have been scrutinizing comet Tempel 1 in advance of Deep Impact's arrival and on June 14 the Hubble Space Telescope caught this image of a gas outburst on that comet. Comets are thought to be collections of dust, rocks and frozen volatiles. As the comet approaches the Sun the increasing temperatures cause the volatiles to turn into gas and flow away from the comet. This is what creates the comet's coma and tail. This process is not uniform and sometimes pockets of gas burst into space in a huge cloud causing a sudden increase in the comet's brightness. Which is exactly what this image from Hubble shows.

Image Credit: NASA/ESA/JHU

A few days later the Deep Impact spacecraft took this series of images showing another gas outburst from Tempel 1. In this series of images the 'nominal' light from the comet has been subtracted from the images so that the gas outburst can be made more highly visible. This is why the comet appears to be missing from the first image in the series.

Image Credit: NASA/JHU

And here is the view of Tempel 1 today - June 30 - just a few days away from the encounter. The comet is still almost three million kilometers from the spacecraft and closing the distance by roughly 12 kilometers each and every second. Things should be getting very exciting in just a few days.

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Click here for the show's intro music.{0:41} Click here for the show's opening and our introduction of Jan Siegel {5:26} Click here for our story about the Cosmos 1 Solar Sail {2:24} Click here to learn about the docking of the Progress with the ISS {2:15} Click here for an update about the Mars Express mission {3:11} Click here for news about the Deep Impact mission {4:41} Click here for our interview with Jan Siegel. {1:08:17} Click here for the show's closing.{1:40} Click here for our current show. Click here for links to all of our previous Shows that you can listen to on the Hour 25 Web Site.

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William F. Nolan     Listen to this show

On Sunday - June 5th, 2005 - our guest on Hour 25 was author William F. Nolan chatting with us about his books as well as the art and craft of writing. It has been said that the luckiest person is the one for whom the work that puts bread on the table is that which he would do, even if he wasn't getting paid to do it. And by that criteria William F. Nolan is a very lucky man. He is someone who lives to write and who has succeeded in doing that in many different genres. As he says, he is a writer. Not a horror writer or a mystery writer or SF writer or a biographer or writer of westerns or a writer of technical manuals. Even though he has done all those things. No, he views himself as a writer because that's what he does. He writes. And what he writes depends on what story he has to tell. And to him, writing is the reason for living. When asked, "When do you take a vacation?", his answer is "When do you take a break from breathing?" Having written 70+ books and numerous scripts for TV and movies, he is a person who has sparked our imaginations for many years. His stories have frightened us with tales of carnivorous trains, diabolical creatures and worlds where it is against the law to grow old. He is a master of the art and craft of writing. It was a great pleasure to sit and chart with him about that which he loves so much.

Sharks Never Sleep and The Black Mask Murders are a couple of really cool books that show off Bill Nolan's considerable talents as a writer. They can be a bit hard to find today, but a few are available to order from his Official Web Site, just scroll down to the bottom of that page and you'll find the appropriate link. We've also recently found some copies at Bookfellows {a.k.a. The Mystery and Imagination Bookshop} in Glendale. Though, you might want to call or check their web site to make sure they still have copies in stock since these books don't seem to spend a lot of time waiting on the shelves for somebody to buy them. Give them a read. I think you'll enjoy them.

Dateline: Mars

Opportunity

Image Credit: NASA/JPL

There two pictures above show just how deep Opportunity's wheels had sunk into the sand of that Martian dune. You can go here to view movies of the rover's wheels spinning in the sand while it tried to extricate itself from this Martian sand trap.

Image Credit: NASA/JPL

And now for the good news. Opportunity has gotten unstuck! Here you see the deep tracks left in the sand as Opportunity worked itself out of this Martian sand trap. Scientists and engineers will now spend time studying this sand dune so they can better understand why it succeeded in capturing Opportunity while other sand dunes were only a minor hindrance to the rover's progress. Doing this will help them to keep from getting caught in the future sand traps.

Spirit

Image Credit: NASA/JPL

While exploring the Columbia Hills Spirit took this false-color image of three rock outcroppings. It then moved closer to them and took closeup images and acquired other data. Studies of such rock outcroppings allow scientists to study native bedrock that has not been covered by decades - or centuries - of drifting dust. Shown below are false color closeups of those three outcroppings.

Image Credit: NASA/JPL Methuselah Image Credit: NASA/JPL Jibsheet Image Credit: NASA/JPL Larry's Lookout

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Click here to listen to the entire show. {43:00} Or

Click here for the show's intro music.{0:41} Click here for the show's opening {13:29} Click here for our interview with William F. Nolan. {27:07} Click here for the show's closing.{1:43} Click here for our current show. Click here for links to all of our previous Shows that you can listen to on the Hour 25 Web Site.

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