As Dawn orbits Ceres, together they orbit the sun. Closer to the master of the solar system, Earth (with its own retinue, including the moon and many artificial satellites) travels faster in its heliocentric orbit because of the sun’s stronger gravitational pull at its location. In December, Earth was on the opposite side of the sun from Dawn, and now the planet’s higher speed is causing their separation to shrink. Earth will get closer and closer until July 22, when it will pass on the inside track, and the distance will increase again.
In the meantime, on April 12, Dawn will be equidistant from the sun and Earth. The spacecraft will be 2.89 AU or 269 million miles (433 million kilometers) from both. At the same time, Earth will be 1.00 AU or 93.2 million miles (150 million kilometers) from the sun.
Illustration of the relative locations (but not sizes) of Earth, the sun, Dawn and Ceres on April 12, 2015. (Earth and the sun are at that location every April 12.) The distance from Earth to Dawn is the same as the distance from the sun to Dawn. The images are superimposed on the trajectory for the entire mission, showing the positions of Earth, Mars, Vesta, and Ceres at milestones during Dawn’s voyage. Compare this to the arrangement in December, when Earth and Dawn were on opposite sides of the sun. Credit: NASA/JPL
It will be as if Dawn is at the tip of a giant celestial arrowhead, pointing the way to a remarkable solar system spectacle. The cosmos should take note! Right there, a sophisticated spaceship from Earth is gracefully descending on a blue-green beam of xenon ions. Finally, the dwarf planet beneath it, a remote remnant from the dawn of the solar system, is lonely no more. Almost 4.6 billion years after it formed, and 214 years after inquisitive creatures on a distant planet first caught sight of it, a mysterious world is still welcoming the new arrival. And as Dawn prepares to settle into its first close orbit, ready to discover secrets Ceres has kept for so long, everyone who shares in the thrill of this grand and noble adventure eagerly awaits its findings. Together, we look forward to the excitement of new knowledge, new insight and new fuel for our passionate drive to explore the universe.
Dawn is 35,000 miles (57,000 kilometers) from Ceres, or 15 percent of the average distance between Earth and the moon. It is also 3.04 AU (282 million miles, or 454 million kilometers) from Earth, or 1,120 times as far as the moon and 3.04 times as far as the sun today. Radio signals, traveling at the universal limit of the speed of light, take 51 minutes to make the round trip.
Dr. Marc D. Rayman
Vielfalt der Farben auf Ceres
Es ist ein kleiner Kunstgriff, mit dem die Planetenforscher den dunklen Zwergplaneten Ceres farbig machen: Mit sieben Farbfiltern des Kamerasystems an Bord der Raumsonde Dawn analysieren sie in verschiedenen Wellenlängenbereichen, wie Ceres das Licht reflektiert. Die Daten stammen dabei aus der Anflugphase, als Dawn sich dem Zwergplaneten näherte, um am 6. März 2015 in die Umlaufbahn von Ceres einzuschwenken. Die Falschfarbenaufnahmen zeigen dabei deutlich, dass Ceres eine Oberfläche aus verschiedenen Materialien hat. "Ceres offenbart immer mehr, dass wir einen spannenden und vielfältigen Himmelskörper untersuchen", sagt Prof. Ralf Jaumann, Planetenforscher am Deutschen Zentrum für Luft- und Raumfahrt (DLR) und Mitglied im Kamerateam der Dawn-Mission. Die Falschfarbenaufnahmen erstellt das Max-Planck-Institut für Sonnensystemforschung. Das DLR-Institut für Planetenforschung wird den Zwergplaneten kartieren und aus tausenden von Einzelaufnahmen dreidimensionale Geländemodelle berechnen.
Bereits die bisherigen Aufnahmen haben gezeigt, dass Ceres von Kratern übersät ist. Selbst Krater von bis zu 300 Kilometern Durchmesser bedecken den Himmelskörper, der 2006 von der Klasse der Asteroiden in die neue Klasse der Zwergplaneten eingeordnet wurde. Fast 1000 Kilometer beträgt sein Durchmesser - damit gehört er zu den größten Objekten im Asteroidengürtel zwischen Jupiter und Mars. Auffällig waren auf den Bildern der Kamera vor allem mehrere helle Punkte in der nördlichen Hemisphäre. Der hellste Fleck befindet sich sehr wahrscheinlich in einem Krater von 92 Kilometern Durchmesser. Auf was die Wissenschaftler dort blicken, wird sich erst untersuchen lassen, wenn Dawn in ihrem Orbit näher um Ceres kreist.
Umrundung nach Umrundung dichter an Ceres heran
Nach der Ankunft am Zwergplaneten verschwand Dawn zunächst hinter der sonnenabgewandten Seite von Ceres und konnte keine weiteren Bilder aufnehmen. Am 10. April 2015 "tauchte" sie wieder auf und schraubt sich nun bei seinen Umrundungen aus einer Entfernung von 42000 Kilometern bis zum 23. April 2015 auf eine Höhe von nur noch 13500 Kilometern hinunter. Dann beginnt die erste wissenschaftliche Phase: "Dann werden wir auch vielleicht schon die ersten Antworten auf unsere Fragen bekommen", sagt DLR-Planetenforscher Prof. Ralf Jaumann.
Mit Dawn fliegen die Planetenforscher direkt in die Vergangenheit unseres Sonnensystems. Damals, als sich vor 4,5 Milliarden Jahren die Planeten bildeten, sorgten Jupiters Kräfte dafür, dass die Asteroiden in diesem Prozess steckenblieben. Als "halbfertige" Planeten konservieren sie so die Anfänge unseres Sonnensystems und erlauben den Blick in dessen Entstehungszeit. Von 2011 bis 2012 besuchte die Dawn-Sonde der NASA bereits den Asteroiden Vesta, ein wasserarmer Asteroid. Mit Ceres, die hinter der Frostgrenze liegt und dementsprechend eisig ist, untersuchen die Wissenschaftler eine ausgesprochen wasserreichen Himmelskörper: Die Forscher vermuten unter seiner Kruste sogar einen Ozean.
Die Mission DAWN wird vom Jet Propulsion Laboratory (JPL) der amerikanischen Weltraumbehörde NASA geleitet. JPL ist eine Abteilung des California Institute of Technology in Pasadena. Die University of California in Los Angeles ist für den wissenschaftlichen Teil der Mission verantwortlich. Das Kamerasystem an Bord der Raumsonde wurde unter Leitung des Max-Planck-Instituts für Sonnensystemforschung in Göttingen in Zusammenarbeit mit dem Institut für Planetenforschung des Deutschen Zentrums für Luft- und Raumfahrt (DLR) in Berlin und dem Institut für Datentechnik und Kommunikationsnetze in Braunschweig entwickelt und gebaut. Das Kamera-Projekt wird finanziell von der Max-Planck-Gesellschaft, dem DLR und NASA/JPL unterstützt.
Dawn Glimpses Ceres' North Pole
This animation shows the north pole of dwarf planet Ceres as seen by the Dawn spacecraft on April 10, 2015. Dawn was at a distance of 21,000 miles (33,000 kilometers) when its framing camera took these images.
Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
After spending more than a month in orbit on the dark side of dwarf planet Ceres, NASA's Dawn spacecraft has captured several views of the sunlit north pole of this intriguing world. These images were taken on April 10 from a distance of 21,000 miles (33,000 kilometers), and they represent the highest-resolution views of Ceres to date.
Subsequent images of Ceres will show surface features at increasingly better resolution.
Dawn arrived at Ceres on March 6, marking the first time a spacecraft has orbited a dwarf planet. Previously, the spacecraft explored giant asteroid Vesta for 14 months from 2011 to 2012. Dawn has the distinction of being the only spacecraft to orbit two extraterrestrial targets.
Ceres, with an average diameter of about 590 miles (950 kilometers), is the largest body in the main asteroid belt between Mars and Jupiter. Dawn has been using its ion propulsion system to maneuver to its first science orbit at Ceres, which it will reach on April 23. The spacecraft will remain at a distance of 8,400 miles (13,500 kilometers) from the dwarf planet until May 9. Afterward, it will make its way to lower orbits.
Dawn's mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, California, for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK, Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team.
NASA Snaps New Views of Dwarf Planet Ceres' Mystery Spots (Video)
NASA's Dawn spacecraft has photographed Ceres' intriguing bright spots again as it prepares to begin its science mission at the dwarf planet.
Dawn, which arrived at Ceres on March 6, imaged the mysterious bright spots on April 14 and 15 during a photography campaign designed to help guide the spacecraft to its first Ceres science orbit by April 23. NASA officials combined the photos into a short video that shows Ceres' bright spots moving as the dwarf planet rotates.
"The approach imaging campaign has completed successfully by giving us a preliminary, tantalizing view of the world Dawn is about to start exploring in detail," Dawn Mission Director and Chief Engineer Marc Rayman, of NASA's Jet Propulsion Laboratory in Pasadena, California, said in a statement. "It has allowed us to start asking some new and intriguing questions."
The new photos were taken when Dawn was about 14,000 miles (22,500 kilometers) above Ceres' north pole, NASA officials said. It's still unclear what, exactly, the white spots are. (Scientists suspect they're deposits of either water ice or salts.)
The bright spots' makeup is just one of many mysteries Dawn will explore with the beginning of intensive observations on April 23. Those initial observations will be made from a circular orbit about 8,400 miles (13,500 km) above the dwarf planet's surface. Then, on May 9, Dawn will begin spiraling closer, to get even better views of Ceres, which, at 590 miles (950 km) wide, is the largest denizen of the main asteroid belt between Mars and Jupiter.
NASA's Dawn spacecraft captured this image of northern Ceres on April 14 and 15, 2015, when it was about 14,000 miles (22,500 kilometers) above the dwarf planet's north pole.
The $466 million Dawn mission launched in September 2007 to study Ceres and Vesta, the asteroid belt's second-biggest body. Both objects are intact protoplanets left over from the solar system's early days; investigating them should reveal key insights about how rocky planets such as Earth came to be, mission officials have said.
Dawn orbited Vesta from July 2011 to September 2012, when the probe departed for Ceres. Dawn is scheduled to keep observing the dwarf planet until June 2016, when it will run out of fuel.
Dawn is the only spacecraft ever to orbit two different bodies beyond the Earth-moon system, and the first probe to study a dwarf planet up close. Another NASA probe is about to get a good look at the solar system's most famous dwarf planet: the New Horizons spacecraft will zoom past Pluto on July 14, lifting the veil on a body that has remained mysterious since its 1930 discovery.
Ceres North Pole View
Several intriguing and as yet unexplained bright spots also dot the surface.
“There is no analog to this visual phenomena in the solar system,” Russell told AmericaSpace.
“When we understand it better we may find an analog that displays itself differently. But this is a total surprise. Right now it seems to be unique!”
These images, from Dawn’s visible and infrared mapping spectrometer (VIR), highlight two regions on Ceres containing bright spots. The top images show a region scientists have labeled “1” and the bottom images show the region labeled “5.” Region 5 contains the brightest spots on Ceres. Credits: NASA/JPL-Caltech/UCLA/ASI/INAF
Dawn made history in March when it simultaneously became the first probe from Earth to reach Ceres as well as the first spacecraft to orbit two extraterrestrial bodies.
It had previously visited Vesta. After achieving orbit in July 2011, Dawn became the first spacecraft from Earth to orbit a body in the main Asteroid Belt, located between Mars and Jupiter.
The probe remained in orbit around the rocky world for an extended mission of 14 months, yielding reams of bonus science images and spectral data for the research teams until departing in September 2012. Vesta is a dry world.
After an interplanetary voyage of some two and a half years and achieving orbit, the ship flew on its planned trajectory on the dark side of Ceres — the side facing away from the sun. It reached a maximum altitude of 46,800 miles (75,400 kilometers) on March 18 based on the spacecraft’s momentum.
Dawn is descending toward the first planned science orbit, which will be 8,400 miles (13,500 kilometers) above the surface. After it arrives on April 23, the spacecraft starts the first “intensive prime science campaign” says NASA.
The first images from the dark side are crescent views taken on April 10 and April 14.
The north pole of Ceres was glimpsed on April 10 in its highest resolution yet. The view is shown herein and taken from a distance of 21,000 miles (33,000 kilometers).
The solar powered probe was approximately 38,000 miles (61,000) kilometers distant at the moment it slipped into orbit around Ceres on March 6.
In sharp contrast to Vesta, Ceres is an icy world.
Scientists believe that Ceres may harbor an ocean of subsurface liquid water as large in volume as the oceans of Earth below a thick icy mantle despite its small size – and thus could be a potential abode for life. Overall Ceres is estimated to be about 25% water by mass.
Dawn’s images obtained thus far reveal Ceres to be a pockmarked world with craters of many sizes, large and small.
Ceres is a huge and mysterious alien world the size of Texas. It measures approximately 590 miles (950 kilometers) in diameter and is nearly round.
It is the largest and most massive object in the main Asteroid Belt, which lies between Mars and Jupiter. Vesta is the second most massive object in the asteroid belt.
Both are fossil remnants dating back to the formation of our Solar System. Exploring the difference between the two will help elucidate our understanding of the origin and evolution of our solar system.
Today, Ceres features a remarkable collection of perhaps 10 or more bright spots. The brightest are a duo of dauntingly mysterious bright spots smack dab in the middle of a 57 miles (92 kilometers) wide crater that look like a pair “eyes.”
The bright spots have not yet been resolved in the camera images. They will be resolved soon, now that Dawn is spiraling down in altitude ever closer towards the surface.
“More detail will emerge after the spacecraft begins its first intensive science phase on April 23,” said Martin Hoffmann, investigator on the Dawn framing camera team, based at the Max Planck Institute for Solar System Research, Göttingen, Germany.
The bright spots are reflected sunlight, but what these reflections represent and the nature of their composition is still unknown.
“The bright spots continue to fascinate the science team, but we will have to wait until we get closer and are able to resolve them before we can determine their source,” Russell noted.
2 Brightest spots on Ceres. This image was taken by NASA’s Dawn spacecraft of dwarf planet Ceres on Feb. 19 from a distance of nearly 29,000 miles (46,000 kilometers). It shows that the brightest spot on Ceres has a dimmer companion, which apparently lies in the same basin. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Dawn is an international science mission run by NASA and equipped with a trio of science instruments from the US, Germany and Italy.
The visible and infrared mapping spectrometer (VIR), provided by Italy is an imaging spectrometer that examines Ceres in visible and infrared light.
The team is using it to determine the temperatures of Ceres surface features, says Federico Tosi, investigator from the VIR instrument team at the Institute for Space Astrophysics and Planetology, and the Italian National Institute for Astrophysics, Rome.
Curiously, the various bright regions on Ceres appear to exhibit different temperature profiles, deepening their mysterious nature. Some spots, including the bright pair, have temperatures similar to their surroundings. Whereas others are cooler by comparison.
Dawn was launched on September 27, 2007 by a United Launch Alliance (ULA) Delta II Heavy rocket from Space Launch Complex-17B (SLC-17B) at Cape Canaveral Air Force Station, Florida.
Stay tuned here for continuing updates on Dawns’ orbital capture and science mission at protoplanet Ceres!