News / Science & Technology

'Dawn' Spacecraft Speeds Toward Asteroid Rendezvous

Artist's rendition of Dawn spacecraft leaving Earth
Artist's rendition of Dawn spacecraft leaving Earth

A large NASA spacecraft named Dawn is barreling toward an orbital rendezvous next month with a huge space rock, and scientists are hoping the unprecedented encounter in the asteroid belt will shed new light on the history of the solar system.  

Vesta is not just any asteroid.  At a whopping 530 kilometers in diameter, Vesta is the second most massive object in the asteroid belt, a vast region between the planets Mars and Jupiter that's filled with rocky debris of all sizes. Vesta is officially described as a "protoplanet" because it almost formed into a planet itself, like Mars or Earth.

And, next month, Vesta is getting a visitor - the Dawn spacecraft.  

Robert Mase is the Dawn project manager at NASA's Jet Propulsion Laboratory in California.

"After traveling for nearly four years, 1.7 billion miles [2.7 billion kilometers] and two laps around the Sun," said Mase, "Dawn is finally on our final approach to Vesta."

NASA's Dawn spacecraft is expected to fall into orbit around Vesta on July 16th.  

For navigation purposes, the spacecraft has sent back pictures of Vesta, and the images are far sharper than the ones from the earth-orbiting Hubble Space Telescope.  Researchers are already expressing surprise at the asteroid's extremely varied surface features, and the real science-gathering is not even expected to begin until August.

But how does a spacecraft get all the way from the Earth to the asteroid belt?  Dawn relies partially on solar energy.  The spacecraft has two solar panels, totaling about 16 meters in length. Tip-to-tip, Dawn's wingspan is about 20 meters, which Mase says makes Dawn the largest interplanetary spacecraft NASA has ever launched.  Plus, Dawn has three ion engines.  That is a type of propulsion that might be familiar to science fiction fans, as an alien spacecraft used it in the 1960s American television series, Star Trek.   

In that episode, Captain Kirk asked Mr. Spock to identify an alien spaceship that was approaching the starship Enterprise.  Spock responded, "Configuration unidentified.  Ion propulsion.  High velocity, though of a unique technology."  

Ion engines are unique - and efficient - because they are powered by electrical fields, not chemical reactions.  

NASA's Mase says ion engines initially produce very low thrust, about equal to the weight of a single piece of paper in your hand.

"So this means we go from zero to 60 [miles per hour, the equivalent of 95 kilometers per hour] in about four days," he explained.  "But the ion engine can continue to thrust and accelerate, day after day, month after month, eventually achieving tremendous velocities over time."  

And Dawn has time.  

The spacecraft will spend a year orbiting Vesta - the first prolonged visit to a main belt asteroid.  It will map the mineral composition and features of Vesta's surface, collect information about Vesta's gravity field, and peer into a massive crater that likely exposes the asteroid's interior.  

Then Dawn will fire its engines again and climb away toward the dwarf planet Ceres, the largest object in the asteroid belt.  It is expected to get there and drop into orbit in early 2015, and spend several months gathering data.

Mase says the Dawn mission is unusual because it is going to rendezvous with not one, but two, bodies in the solar system.

Researchers say the Vesta asteroid is no stranger to Earth.  Chunks of the protoplanet have been knocked off during collisions with other space rocks, and scientists believe many of the meteorites that are found on Earth - perhaps one of out 20 - originated on Vesta.   

You May Like

Pundits Split Over Long-Term US Role in Afghanistan

Security pact remains condition for American presence beyond 2014; deadline criticized More

US Eyes Islamic State Threat

Officials warn that IS could pose a threat to US homeland More

Video Ukraine: Captured Troops Proof of Russian Role in Separatist Fight

Moscow says Russian troops crossed into Ukrainian territory by mistake More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Scientists Unlock Mystery of Bird Flocksi
X
George Putic
August 25, 2014 4:00 PM
How can flocks of birds, schools of fish or herds of antelope suddenly change direction -- all the individuals adjusting their movement in concert, at seemingly the same time? British researchers now have some insights into this behavior, which has puzzled scientists for a long time. VOA's George Putic has more.
Video

Video Scientists Unlock Mystery of Bird Flocks

How can flocks of birds, schools of fish or herds of antelope suddenly change direction -- all the individuals adjusting their movement in concert, at seemingly the same time? British researchers now have some insights into this behavior, which has puzzled scientists for a long time. VOA's George Putic has more.
Video

Video Ukraine: Captured Troops Proof of Russian Role in Separatist Fight

Ukrainian officials say they have captured Russian soldiers on Ukrainian territory -- the latest accusation of Moscow's involvement in the conflict in eastern Ukraine. VOA's Gabe Joselow reports from the Ukrainian side of the battle, where soldiers are convinced of Russia's role.
Video

Video Rubber May Soon Come From Dandelions

Synthetic rubber has been around for more than a century, but quality tires for cars, trucks and aircraft still need up to 40 percent or more natural rubber content. As the source of natural rubber, the rubber tree, is prone to disease and can be affected by bad weather. So scientists are looking for replacements. And as VOA’s George Putic reports, they may have found one in a ubiquitous weed.
Video

Video Jewish Life in Argentina Reflected in Yiddish Tango

Jewish people from across Europe and Russia have been immigrating to Argentina for hundreds of years. They brought with them dance music that were eventually mixed with Argentine tango. The result is Yiddish tango -- a fusion of melodies and cultural experiences that is still evolving today. Elizabeth Lee reports from the Skirball Cultural Center in Los Angeles, where one band is bringing Yiddish tango to an American audience.
Video

Video Peace Returns to Ferguson as Community Tries to Heal

Thousands of people nationwide are expected to attend funeral services Monday in the U.S. Midwestern city of St. Louis, Missouri, for Michael Brown, the unarmed African-American teenager who was fatally shot by a white police officer August 9 in the St. Louis suburb of Ferguson. The shooting touched off days of violent demonstrations there, resulting in more than 100 arrests. VOA's Chris Simkins reports from Ferguson where the community is trying to move on after weeks of racial tension.
Video

Video Meeting in Minsk May Hinge on Putin Story

The presidents of Russia and Ukraine are expected to meet face-to-face Tuesday in Minsk, along with European leaders, for talks on the situation in Ukraine. Political analysts say the much welcomed dialogue could help bring an end to months of deadly clashes between pro-Russia separatists and Ukrainian forces in the country's southeast. But much depends on the actions of one man, Russian President Vladimir Putin. VOA's Daniel Schearf reports from Moscow.
Video

Video Artists Shun Russia's Profanity Law

Russia in July enacted a law threatening fines for publicly displayed profanity in media, films, literature, music and theater. The restriction, the toughest since the Soviet era, aims to protect the Russian language and culture and has been welcomed by those who say cursing is getting out of control. But many artists reject the move as a patronizing and ineffective act of censorship in line with a string of conservative morality laws. VOA's Daniel Schearf reports from Moscow.
Video

Video British Fighters on Frontline of ISIS Information War

Security services are racing to identify the Islamic State militant who beheaded U.S. journalist James Foley in Syria. The murderer spoke English on camera with a British accent. It’s estimated that several hundred British citizens are fighting for the Islamic State, also called ISIL or ISIS, alongside thousands of other foreign jihadists. Henry Ridgwell reports for VOA from the center of the investigation in London.

AppleAndroid