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

India PM Modi's Party Distances Itself From Religious Conversions

BJP under fire for being slow to rein in hardline affiliate groups allegedly trying to promote Hindu-dominant agenda by luring Muslims and Christians to convert More

Anti-Whaling Group Found in Contempt of Court

Radical environmentalists who threw acid and smoke bombs at Japanese whalers in the waters off Antarctica continue their campaign to disrupt Japan's annual whale hunt More

UN's Ban Urges End to Discrimination Against Ebola Workers

Ban was speaking in Guinea on the second day of a whistle-stop tour aimed at thanking healthcare workers of the countries at the heart of the epidemic 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.
US Decision on Cuba Underscores Divisions Among Miami Cubansi
X
Sharon Behn
December 19, 2014 9:34 PM
For decades, older, more conservative Cubans have been gathering at Café Versailles on the corner of Calle Ocho to eat Cuban food and talk politics. After hearing of President Barack Obama’s decision, a number of them gathered in front of the café with posters to protest. VOA's Sharon Behn reports on the situation.
Video

Video US Decision on Cuba Underscores Divisions Among Miami Cubans

For decades, older, more conservative Cubans have been gathering at Café Versailles on the corner of Calle Ocho to eat Cuban food and talk politics. After hearing of President Barack Obama’s decision, a number of them gathered in front of the café with posters to protest. VOA's Sharon Behn reports on the situation.
Video

Video Three Cities Bid for Future Obama Presidential Library

President Barack Obama still has two years left in his term in office, but the effort to establish his post-presidential library is already underway. The bid for the Obama Presidential Library is down to four locations in three states -- New York, Hawaii, and Illinois. As VOA’s Kane Farabaugh reports, each of them played an important part in the president’s life before he reached the White House.
Video

Video Cuba Deal is Major Victory for Pope’s Diplomatic Initiatives

Pope Francis played a key role in brokering the US-Cuba deal that was made public earlier this week. It is the most stunning success so far in a series of peacemaking efforts by the pontiff. VOA religion reporter Jerome Socolovsky has more.
Video

Video Fears of More Political Gridlock in 2015

2014 proved to be a difficult year politically for President Barack Obama and a very good year for the U.S. Republican Party. Republican gains in the November midterm elections gave them control of the Senate and House of Representatives for the next two years -- setting the stage for more confrontation and gridlock in the final two years of the Obama presidency. VOA National Correspondent Jim Malone has a preview from Washington.
Video

Video Sudan School Becomes Target of Aerial Attacks

The school dropout rate is at an all-time high in Sudan's South Kordofan state because many schools have been destroyed during the three-year civil war between the government and SPLA-N rebel forces. Adam Bailes visited Sudan's Nuba Mountains' region and reports many children are simply too scared to go to school
Video

Video VOA Reporter Tours Devastated Peshawar School

Islamist militants wearing military uniforms and strapped with explosives attacked a military run school Tuesday in the northwestern Pakistani city of Peshawar. At least 141 people were killed in the horrific attack, most of them young students. VOA reporter Ayaz Gul visited the devastated school and attended the funeral of the principal who courageously tried to save her students from the deadly attack.
Video

Video Nigerians Fleeing Boko Haram Languish in Camp Near Capital

In its five-year effort to impose Islamic law in northeastern Nigeria, the Boko Haram extremist group has killed thousands of people and forced hundreds of thousands to flee. Some of those who ran for their lives now live in squalor on the edges of the capital, Abuja. Chris Stein reports for VOA.
Video

Video Aceh Rebuilt Decade After Tsunami, But Scars Remain

On December 26, 2004 there was an earthquake in the Indian Ocean so powerful it caused the Earth’s axis to wobble a few centimeters. Onshore on the island of Sumatra, the resulting tsunami was devastating. A decade later, VOA Correspondent Steve Herman reports from Banda Aceh, Indonesia, where although there is little remaining evidence of the physical devastation, the psychological scars among survivors remain.

All About America

AppleAndroid