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

Is Air Travel Safe?

Aviation expert says despite tragic losses of Malaysian Airlines flights 370 and 17, industry experienced lowest fatality rate in recorded history last year More

Multimedia 100 Days Later, Nigerian Girls Still Held

Activists holding rallies in Nigeria and several other countries to mark 100th day of captivity for more than 200 schoolgirls being held by Boko Haram More

Chocolate Too Bitter? Swap Sugar for Mushrooms

US food technology company develops fermentation process using mushrooms to reduce bitterness in cocoa beans, believes it will cut sugar content in candy 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 Carriers Suspend Travel to Israeli
X
Carolyn Presutti
July 23, 2014 1:21 AM
The United States is prohibiting American carriers from flying to Israel's airport in Tel Aviv for 24 hours, because of rising violence between Israel and Hamas militants. The action was announced on Tuesday, after a rocket fired by Hamas militants in the Gaza Strip landed near the airport. As VOA's Carolyn Presutti tells us, international officials soon may have to determine which combat zones are too dangerous for commercial flights.
Video

Video US Carriers Suspend Travel to Israel

The United States is prohibiting American carriers from flying to Israel's airport in Tel Aviv for 24 hours, because of rising violence between Israel and Hamas militants. The action was announced on Tuesday, after a rocket fired by Hamas militants in the Gaza Strip landed near the airport. As VOA's Carolyn Presutti tells us, international officials soon may have to determine which combat zones are too dangerous for commercial flights.
Video

Video NASA Focuses on Earth-Like Planets

For decades, looking for life elsewhere in the universe meant listening for signals that could be from distant civilizations. But recent breakthroughs in space technology refocused some of that effort toward finding planets that may harbor life, even in its primitive form. VOA’s George Putic reports on a recent panel discussion at NASA’s headquarters, in Washington.
Video

Video IAEA: Iran Turns its Enriched Uranium Into Less Harmful Form

Iran has converted its stockpiles of enriched uranium into a less dangerous form that is more difficult to use for nuclear weapons, according to the United Nations’ Atomic Energy Agency. The move complies with an interim deal reached with Western powers on Iran's nuclear program last year, in exchange for easing of sanctions. Henry Ridgwell reports for VOA from London.
Video

Video Relic of Saint Draws Catholics Worried About Immigration Issue

A Roman Catholic saint who is a figure of devotion for those crossing the border into the United States is attracting believers concerned about the plight of undocumented immigrants. Mike O'Sullivan reports from Los Angeles, where a relic of Saint Toribio has drawn thousands to local churches.
Video

Video US Awards Medal of Honor for Heroics in Bloodiest of Afghan Battles

U.S. combat troops are withdrawing from Afghanistan, on pace to leave the country by the end of this year. But on Monday, U.S. President Barack Obama took time to honor a soldier whose actions while under fire in Afghanistan earned him the Medal of Honor. VOA's Jeff Seldin has more from the Pentagon.
Video

Video Ukraine Rebels Surrender MH17 Black Boxes

After days of negotiations, a senior separatist leader handed over two black boxes from an airliner downed over eastern Ukraine to Malaysian experts early Tuesday. While on Monday, the U.N. Security Council unanimously demanded that armed groups controlling the crash site allow safe and unrestricted access to the wreckage.
Video

Video In Cambodia, HIV Diagnosis Brings Deadly Shame

Although HIV/AIDS is now a treatable condition, a positive diagnosis is still a life altering experience. In Cambodia, people living with HIV are often disowned by friends, family and the community. This humiliation can be unbearable. We bring you one Cambodian woman’s struggle to overcome a life tragedy and her own HIV positive diagnosis.
Video

Video Nature of Space Exploration Enters New Age

Forty-five years ago this month, the first humans walked on the moon. It was during an era of the space race between the United States and the Soviet Union. World politics have changed since then and -- as Elizabeth Lee reports -- so has the nature of space exploration.

AppleAndroid