Subscribe free to our newsletters via your
. 24/7 Space News .

Dawn races into 2013 on target for Ceres
by Marc Rayman for Dawn News
Pasadena CA (JPL) Jan 04, 2013

illustration only

Dawn concludes 2012 almost 13,000 times farther from Vesta than it began the year. At that time, it was in its lowest orbit, circling the alien world at an average altitude of only 210 kilometers (130 miles), scrutinizing the mysterious protoplanet to tease out its secrets about the dawn of the solar system.

To conduct its richly detailed exploration, Dawn spent nearly 14 months in orbit around Vesta, bound by the behemoth's gravitational grip. In September they bid farewell, as the adventurer gently escaped from the long embrace and slipped back into orbit around the sun. The spaceship is on its own again in the main asteroid belt, its sights set on a 2015 rendezvous with dwarf planet Ceres. Its extensive ion thrusting is gradually enlarging its orbit and taking it ever farther from its erstwhile companion as their solar system paths diverge.

Meanwhile, on faraway Earth (and all the other locations throughout the cosmos where Dawnophiles reside), the trove of pictures and other precious measurements continue to be examined, analyzed, and admired by scientists and everyone else who yearns to glimpse distant celestial sights. And Earth itself, just as Vesta, Ceres, Dawn, and so many other members of the solar system family, continues to follow its own orbit around the sun.

Thanks to a coincidence of their independent trajectories, Earth and Dawn recently reached their smallest separation in well over a year, just as the tips of the hour hand and minute hand on a clock are relatively near every 65 minutes, 27 seconds. On Dec. 9, they were only 236 million kilometers (147 million miles) apart. Only?

In human terms, this is not particularly close. Take a moment to let the immensity of their separation register. The International Space Station, for example, firmly in orbit around Earth, was 411 kilometers (255 miles) high that day, so our remote robotic explorer was 575 thousand times farther. If Earth were a soccer ball, the occupants of the orbiting outpost would have been a mere seven millimeters (less than a third of an inch) away.

Our deep-space traveler would have been more than four kilometers (2.5 miles) from the ball. So although the planet and its extraterrestrial emissary were closer than usual, they were not in close proximity. Dawn remains extraordinarily far from all of its human friends and colleagues and the world they inhabit.

As the craft reshapes its solar orbit to match Ceres's, it will wind up farther from the sun than it was while at Vesta. (As a reminder, see the table here that illustrates Dawn's progress to each destination on its long interplanetary voyage.)

We saw recently, however, that the route is complex, and the spacecraft is temporarily approaching the sun. Before the ship has had time to swing back out to a greater heliocentric range, Earth will have looped around again, and the two will briefly be even a little bit closer early in 2014. After that, however, they will never be so near each other again, as Dawn will climb higher and higher up the solar system hill, its quest for new and exciting knowledge of distant worlds taking it farther from the sun and hence from Earth.

Although our cosmic ambassador is much, much too remote to be discerned with our humble eyes, our far more powerful minds' eyes can locate it. As a convenient guide to begin, you can use the moon on Jan. 21. The details of the geometry will be somewhat dependent on your terrestrial position, which determines when the moon is above your horizon and how it aligns with the more distant cosmic landscape.

Nevertheless, if you look at the moon that day, Dawn will appear to be nearby in the sky (although more than 670 times farther away). For observers in the continental United States, as the sun sets, the probe will be about five degrees to the east (left) of the moon, or about the width of three fingers held at arm's length. (Your correspondent has found that the measurement works best if you use not only your own fingers, but also your own arm.)

As the evening progresses, they will draw closer and closer together. By the time the moon sinks below the western horizon at around 3:30 a.m. on Jan. 22, they will be separated by less than two degrees for observers on the east coast, and those on the west coast will find Dawn less than one degree away.

After using the moon to guide your eyes to the general location of the intrepid ship in the sky, let your mind take over. Allow it to transport you far, far into space, beyond all the human-made satellites around Earth, beyond the moon, beyond the orbit of Mars, and continue out farther than the sun (although in a different direction).

Deep in the main asteroid belt, where no other spacecraft has ever taken up permanent residence and farther than all but a handful of probes have ever ventured, you can espy Dawn. Its long solar array wings, spanning nearly 20 meters (almost 65 feet) are pointing at the sun, capturing its light.

A lovely beam of xenon ions glows blue-green as it propels the craft toward Ceres. Almost like a living creature, it is intensely active within; computers and myriad electronic circuits, heaters, and other components are working together to keep the ship flying true. Out there, in that direction, alone, far away from any firm surface or familiar ground, this Brobdingnagian celestial dragonfly flies gracefully, silently, and patiently toward its next planetary perch.

Dawn is 2.7 million kilometers (1.7 million miles) from Vesta and 57 million kilometers (38 million miles) from Ceres. It is also 1.65 AU (247 million kilometers or 153 million miles) from Earth, or 625 times as far as the moon and 1.68 times as far as the sun today. Radio signals, traveling at the universal limit of the speed of light, take 27 minutes to make the round trip.


Related Links
Dawn at JPL
Asteroid and Comet Mission News, Science and Technology

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

"All-Clear" Asteroid Will Miss Earth in 2040
Hilo HI (SPX) Dec 24, 2012
Using the Gemini North telescope on Mauna Kea, Hawai'i a team of astronomers from the University of Hawaii's Institute for Astronomy (IfA) have confirmed that the chance of asteroid 2011 AG5 impacting Earth in 2040 is no longer a significant risk - prompting a collective sigh-of-relief. Previously, scientists estimated that the risk of this 140-meter-diameter (about the length of two Ameri ... read more

Russia designs manned lunar spacecraft

GRAIL Lunar Impact Site Named for Astronaut Sally Ride

NASA probes crash into the moon

No plans of sending an Indian on moon

Stanford researchers develop acrobatic space rovers to explore moons and asteroids

Researchers Identify Water Rich Meteorite Linked To Mars Crust

Mars meteorite has significant water

'Spiky' rovers could explore martian moon

Congress Approves Bill Supporting Human Space Exploration

China's Chengdu aiming to be world's next Silicon Valley

Satellite highs, suspension lows for Indian space sector in 2012

NASA's Destination Station Exhibit Opens In Mesa, Arizona

Mr Xi in Space

China plans manned space launch in 2013: state media

China to launch manned spacecraft

Tiangong 1 Parked And Waiting As Shenzhou 10 Mission Prep Continues

Station Crew Ringing in New Year

Expedition 34 Ready to Ring in New Year

New ISS crew docked at Space Station

Expedition 34 Spends Christmas in Space

CSF Applauds Passage Of Risk-Sharing Regime Extension For Launch Industry

Rokot Launch Set for January 15

Russian rocket launch rescheduled

Investigation into Proton Launch Anomaly Continues as Root Cause is being Evaluated

Billions and Billions of Planets

ALMA Shows How Young Star and Planets Grow Simultaneously

ALMA Sheds Light on Planet-Forming Gas Streams

A stray planet

COM DEV wins commercial contract from MacDonald Dettwiler and Associates

Thai 'scavengers club' turns trash to treasure

Malaysia convoy in Australia rare earth plant protest

All Systems Go for Highest Altitude Supercomputer

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement