DEEP NEWS Newsletter for the NASA Deep Impact mission Issue 9, March 2004

Status Report From: Jet Propulsion Laboratory
Posted: Monday, March 22, 2004

image Welcome to our March issue of Deep News, the newsletter that gives you the latest update on the Deep Impact mission to put a crater in Comet Tempel 1. A year from now we will be speeding toward Tempel 1 to look beneath its surface by excavating a crater the size of a football stadium using an impactor spacecraft. Since this will be the first mission to offer you a peak inside of a comet nucleus, scientists look forward to finding new clues to the formation of the solar system hidden deep inside. To learn more about the Deep Impact mission, visit our web site at:


If you are one of the over 625,000 people who entered our name collection campaign, Send Your Name to a Comet, then we have a picture for you. The CD containing the names is safely sealed onto the surface of the copper nosed impactor that will make a crater in Comet Tempel 1 on July 4th, 2005. The CD, along with both the flyby and impactor spacecraft, will go through environmental testing later this month.


This month, PI, Mike A'Hearn reports on the launch of the European Space Agency's Rosetta mission and its relationship to the Deep Impact mission.


Jessica Sunshine is a member of the Deep Impact science team. When she isn't preparing to use the IR spectrometer to tell us about the composition and geology of Comet Tempel 1, you might find her playing the viola for an orchestra in the Washington, D.C. area.


Data from the Deep Impact mission will answer many of our questions about the structure and composition of comets but what have some of our ancient cultures thought of them? Are they omens of disaster or messengers of the gods? Noah Goldman, a student intern from the College Park Scholars program at the University of Maryland decided to explore this issue.


Actually, early cultures where not even aware of comets as being icy bodies in the Solar System. So every comet they saw was a 'new' demon in their belief system. It wasn't until the late 1600's that astronomers thought that some comets that had been observed through the centuries might be the same comets seen over and over. In fact, the "first" comet that is defined as periodic, meaning that it is seen on a regular basis, is comet Halley. It is named after Edmund Halley who noticed that every 76 years there was a comet visible. He was able to predict when that one comet would return. Unfortunately, he died before he could see his prediction come true, but the comet was still named after him. How was he able to predict the return of this comet? Well, every comet has a very distinctive orbit or elliptical path around the sun. That orbit can be defined with a set of numbers that we refer to as "orbital elements." Since the path of the comets (and the planets) are in three dimensional space, we need at least 3 numbers to orient that path, a few others to define the size and shape, and a few to define the position in the orbit. Using these orbital elements, we can then calculate a comet's past and future positions to predict when it will next be observable. If a comet is found by chance, one has to observe it long enough to trace its path on the sky, fit it to an ellipse to determine the orbital elements, then compare those values to a table of known comet orbital elements to identify it.

We will be adding some more about orbital elements to the website in the future so stay tuned.

In the meantime take a look at,

CAN YOU ANSWER THIS? Play the "Can You Answer This" game that tests your skills in treasure hunting around the Deep Impact web site for clues to the answers. If you didn't get the chance to play our past games, you may want to visit:

If you played Can You Answer This? in February, here are the answers:

And now - on to March 2004 Can You Answer This. From now on, the answers will be available to you as well - but no cheating!


Ray Brown, a science journalist at the University of Maryland joins our web team of writers. Over the coming months, Ray will explain how the activity of impacting Comet Tempel 1 will answer the science questions posed by the Deep Impact science team. It's trickier than you think so you'll want to see each upcoming issue. But first, in case you are missing any of the basics for our mission, take a look at Ray's introduction and you'll be ready next month when we start digging into those science questions.

WHERE ARE WE MAKING A DEEP IMPACT? The answer is - all over the United States. If you visited Carl's Junior or Hardees during January and February, you may have purchased your own toy comet and Deep Impact trading card with your children's meal. The swirling comet was one of four special offer toys in their NASA Kids series.

The Deep Impact mission is a partnership among the University of Maryland (UMD), the California Institute of Technology's Jet Propulsion Laboratory (JPL) and Ball Aerospace and Technology Corp (BATC). Deep Impact is a NASA Discovery mission, eighth in a series of low-cost, highly focused space science investigations. See or our mirror site at

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