Home
In this issue

Jonathan Tobin: Defending the Right to a Jewish State

Heather Hale: Compliment your kids without giving them big heads

Megan Shauri: 10 ways you are ruining your own happiness

Carolyn Bigda: 8 Best Dividend Stocks for 2015

Kiplinger's Personal Finance editors: 7 Things You Didn't Know About Paying Off Student Loans

Samantha Olson: The Crucial Mistake 55% Of Parents Are Making At Their Baby's Bedtime

Densie Well, Ph.D., R.D. Open your eyes to yellow vegetables

The Kosher Gourmet by Megan Gordon With its colorful cache of purples and oranges and reds, COLLARD GREEN SLAW is a marvelous mood booster --- not to mention just downright delish
April 18, 2014

Rabbi Yonason Goldson: Clarifying one of the greatest philosophical conundrums in theology

Caroline B. Glick: The disappearance of US will

Megan Wallgren: 10 things I've learned from my teenagers

Lizette Borreli: Green Tea Boosts Brain Power, May Help Treat Dementia

John Ericson: Trying hard to be 'positive' but never succeeding? Blame Your Brain

The Kosher Gourmet by Julie Rothman Almondy, flourless torta del re (Italian king's cake), has royal roots, is simple to make, . . . but devour it because it's simply delicious

April 14, 2014

Rabbi Dr Naftali Brawer: Passover frees us from the tyranny of time

Greg Crosby: Passing Over Religion

Eric Schulzke: First degree: How America really recovered from a murder epidemic

Georgia Lee: When love is not enough: Teaching your kids about the realities of adult relationships

Cameron Huddleston: Freebies for Your Lawn and Garden

Gordon Pape: How you can tell if your financial adviser is setting you up for potential ruin

Dana Dovey: Up to 500,000 people die each year from hepatitis C-related liver disease. New Treatment Has Over 90% Success Rate

Justin Caba: Eating Watermelon Can Help Control High Blood Pressure

The Kosher Gourmet by Joshua E. London and Lou Marmon Don't dare pass over these Pesach picks for Manischewitz!

April 11, 2014

Rabbi Hillel Goldberg: Silence is much more than golden

Caroline B. Glick: Forgetting freedom at Passover

Susan Swann: How to value a child for who he is, not just what he does

Cameron Huddleston: 7 Financial Tasks You Should Tackle Right Now

Sandra Block and Lisa Gerstner: How to Profit From Your Passion

Susan Scutti: A Simple Blood Test Might Soon Diagnose Cancer

Chris Weller: Have A Slow Metabolism? Let Science Speed It Up For You

The Kosher Gourmet by Diane Rossen Worthington Whitefish Terrine: A French take on gefilte fish

April 9, 2014

Jonathan Tobin: Why Did Kerry Lie About Israeli Blame?

Samuel G. Freedman: A resolution 70 years later for a father's unsettling legacy of ashes from Dachau

Jessica Ivins: A resolution 70 years later for a father's unsettling legacy of ashes from Dachau

Kim Giles: Asking for help is not weakness

Kathy Kristof and Barbara Hoch Marcus: 7 Great Growth Israeli Stocks

Matthew Mientka: How Beans, Peas, And Chickpeas Cleanse Bad Cholesterol and Lowers Risk of Heart Disease

Sabrina Bachai: 5 At-Home Treatments For Headaches

The Kosher Gourmet by Daniel Neman Have yourself a matzo ball: The secrets bubby never told you and recipes she could have never imagined

April 8, 2014

Lori Nawyn: At Your Wit's End and Back: Finding Peace

Susan B. Garland and Rachel L. Sheedy: Strategies Married Couples Can Use to Boost Benefits

David Muhlbaum: Smart Tax Deductions Non-Itemizers Can Claim

Jill Weisenberger, M.S., R.D.N., C.D.E : Before You Lose Your Mental Edge

Dana Dovey: Coffee Drinkers Rejoice! Your Cup Of Joe Can Prevent Death From Liver Disease

Chris Weller: Electric 'Thinking Cap' Puts Your Brain Power Into High Gear

The Kosher Gourmet by Marlene Parrish A gift of hazelnuts keeps giving --- for a variety of nutty recipes: Entree, side, soup, dessert

April 4, 2014

Rabbi David Gutterman: The Word for Nothing Means Everything

Charles Krauthammer: Kerry's folly, Chapter 3

Amy Peterson: A life of love: How to build lasting relationships with your children

John Ericson: Older Women: Save Your Heart, Prevent Stroke Don't Drink Diet

John Ericson: Why 50 million Americans will still have spring allergies after taking meds

Cameron Huddleston: Best and Worst Buys of April 2014

Stacy Rapacon: Great Mutual Funds for Young Investors

Sarah Boesveld: Teacher keeps promise to mail thousands of former students letters written by their past selves

The Kosher Gourmet by Sharon Thompson Anyone can make a salad, you say. But can they make a great salad? (SECRETS, TESTED TECHNIQUES + 4 RECIPES, INCLUDING DRESSINGS)

April 2, 2014

Paul Greenberg: Death and joy in the spring

Dan Barry: Should South Carolina Jews be forced to maintain this chimney built by Germans serving the Nazis?

Mayra Bitsko: Save me! An alien took over my child's personality

Frank Clayton: Get happy: 20 scientifically proven happiness activities

Susan Scutti: It's Genetic! Obesity and the 'Carb Breakdown' Gene

Lecia Bushak: Why Hand Sanitizer May Actually Harm Your Health

Stacy Rapacon: Great Funds You Can Own for $500 or Less

Cameron Huddleston: 7 Ways to Save on Home Decor

The Kosher Gourmet by Steve Petusevsky Exploring ingredients as edible-stuffed containers (TWO RECIPES + TIPS & TECHINQUES)

Jewish World Review

How the Dawn mission works

By Marshall Brain

Printer Friendly Version
Email this article

http://www.JewishWorldReview.com | (MCT) If everything goes as planned, NASA will launch an incredibly interesting mission on June 30. It is called the Dawn mission, and its goal is to visit and map out the two largest asteroids in the asteroid belt.

The first asteroid on the menu is Vesta. At 321 miles long, it is the second largest asteroid. For comparison, the earth's moon is about 2,100 miles in diameter. On a planetary scale, Vesta is tiny. But in terms of asteroids, it is huge. Like most asteroids, Vesta is a big, rocky, irregularly shaped lump.

The second asteroid is named Ceres. This asteroid is so big that it actually looks spherical like a planet, but at 600 miles in diameter it is much smaller than a normal planet. The most interesting thing about Ceres is its similarities to Earth. Scientists believe Ceres has an iron core and possibly lots of fresh water (in the form of ice) stored underneath the surface.

One unusual part of the Dawn mission is the engine that the spacecraft uses. Instead of using big, fiery chemical rockets to blast from one asteroid to another, Dawn is using a Xenon ion drive powered by huge, 10,000-watt solar panels. The ion drive uses electrical fields to turn Xenon atoms into ions. Then the engine shoots the ions out of the nozzle at 78,000 miles per hour. The total thrust that this engine produces is very small (it would take four days for the spacecraft to accelerate from zero to 60 using this propulsion system), but the engine can fire for months when it needs to. The Dawn spacecraft will be the fastest ship NASA has ever built and will also be the first to orbit one body, then move to a second body and orbit it.

Here is how the mission will unfold. A Delta 2 rocket will take the Dawn spacecraft out of earth's orbit. Then the ion engine will fire and send the spacecraft toward Mars. Dawn will slingshot past Mars in March of 2009, arriving at Vesta in October of 2011. In April 2012 the spacecraft will fire its ion drive again to leave Vesta and arrive at Ceres in February of 2015, having traveled a total of three billion miles.

The goals of the mission are to map the two asteroids using an optical camera and then use two different kinds of spectrometers to see what the asteroids are made of. The first spectrometer is like a super-specialized camera. It has only one pixel of resolution, but can deliver very precise color readings from this pixel by looking at visible and infrared light. With this data, scientists can identify different minerals seen on the surface of the asteroid. The second spectrometer is the gamma ray and neutron spectrometer. It can see the gamma rays and neutrons that the asteroids emit. This instrument can detect things like hydrogen, carbon, oxygen and nitrogen, along with radioactive elements.

To send all of its data and images back to earth, Dawn uses a 100-watt radio and a 5-foot diameter dish antenna. Back here on earth, gigantic dish antennas up to 200 feet in diameter pick up the faint signals so that computers can decode them.

One of the things that NASA scientists hope to discover is why one asteroid looks like a lump while the other is a nice, spherical, planet-like object. What would cause the two asteroids to be so different? Using the data that Dawn gathers, scientists may be able to discover the reason. Another goal is to understand exactly what elements make up these asteroids. The thought is that asteroids can tell us what the earth might have looked like when it first formed, and with this information we can learn more about the origins of the earth, Venus and Mars. We may also learn a great deal about the beginnings of our solar system.

Because of the long timeline for the mission, we won't hear much about Dawn after its launch. Then, four years from now, it will be in the news again as images start streaming back from Vesta and we learn new things about the asteroid belt. Then things will get quiet again for 3 more years until, once again, images start arriving from Ceres. It is a very long mission, and one that will reveal many new things about our solar system's origins.

Every weekday JewishWorldReview.com publishes what many in the media and Washington consider "must-reading". Sign up for the daily JWR update. It's free. Just click here.

Comment by clicking here.



Previously:


How Kassam rockets work
How the North American Eagle works
Why aren't we flying to work?
How tofu and soy milk work
How Colony Collapse Disorder works
How airbags work
How the U.S. income tax works
How gum works
How caffeine works
How Daylight Saving Time works
How a cruise missile works
How snow making works

© 2007, How Stuff Works Inc. Distributed by McClatchy-Tribune Information Services.

Columnists

Toons

Lifestyles