Ceres
JPL News – Day in Review
Features on dwarf planet Ceres that piqued the interest of scientists throughout 2015 stand out in exquisite detail in the latest images from NASA’s Dawn spacecraft, which recently reached its lowest-ever altitude at Ceres.
Dawn took these images near its current altitude of 240 miles (385 kilometers) from Ceres, between Dec. 19 and 23, 2015.
Kupalo Crater, one of the youngest craters on Ceres, shows off many fascinating attributes at the high image resolution of 120 feet (35 meters) per pixel. The crater has bright material exposed on its rim, which could be salts, and its flat floor likely formed from impact melt and debris. Researchers will be looking closely at whether this material is related to the “bright spots” of Occator Crater. Kupalo, which measures 16 miles (26 kilometers) across and is located at southern mid-latitudes, is named for the Slavic god of vegetation and harvest.
“This crater and its recently-formed deposits will be a prime target of study for the team as Dawn continues to explore Ceres in its final mapping phase,” said Paul Schenk, a Dawn science team member at the Lunar and Planetary Institute, Houston.
Dawn’s low vantage point also captured the dense network of fractures on the floor of 78-mile-wide (126-kilometer-wide) Dantu Crater. One of the youngest large craters on Earth’s moon, called Tycho, has similar fractures. This cracking may have resulted from the cooling of impact melt, or when the crater floor was uplifted after the crater formed.
A 20-mile (32-kilometer) crater west of Dantu is covered in steep slopes, called scarps, and ridges. These features likely formed when the crater partly collapsed during the formation process. The curvilinear nature of the scarps resembles those on the floor of Rheasilvia, the giant impact crater on protoplanet Vesta, which Dawn orbited from 2011 to 2012.
Dawn’s other instruments also began studying Ceres intensively in mid-December. The
visible and infrared mapping spectrometer is examining how various wavelengths of light are reflected by Ceres, which will help identify minerals present on its surface.
Dawn’s gamma ray and neutron detector (GRaND) is also keeping scientists busy. Data from GRaND help researchers understand the abundances of elements in Ceres’ surface, along with details of the dwarf planet’s composition that hold important clues about how it evolved.
The spacecraft will remain at its current altitude for the rest of its mission, and indefinitely afterward. The end of the prime mission will be June 30, 2016.
“When we set sail for Ceres upon completing our Vesta exploration, we expected to be surprised by what we found on our next stop. Ceres did not disappoint,” said Chris Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles. “Everywhere we look in these new low- altitude observations, we see amazing landforms that speak to the unique character of this most amazing world.”
Dawn is the first mission to visit a dwarf planet, and the first mission outside the Earth-moon system to orbit two distinct solar system targets. After orbiting Vesta for 14 months in 2011 and 2012, it arrived at Ceres on March 6, 2015.
Dawn’s mission is managed by the Jet Propulsion Laboratory 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, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit: http://dawn.jpl.nasa.gov/mission
More information about Dawn is available at the following sites: http://dawn.jpl.nasa.gov and http://www.nasa.gov/dawn
Lowdown on Ceres: Images From Dawn’s Closest Orbit
NASA’s Dawn spacecraft, cruising in its lowest and final orbit at dwarf planet Ceres, has delivered the first images from its best-ever viewpoint. The new images showcase details of the cratered and fractured surface. 3-D versions of two of these views are also available.
Dawn took these images of the southern hemisphere of Ceres on Dec. 10, at an approximate altitude of 240 miles (385 kilometers), which is its lowest-ever orbital altitude. Dawn will remain at this altitude for the rest of its mission, and indefinitely afterward. The resolution of the new images is about 120 feet (35 meters) per pixel.
Among the striking views is a chain of craters called Gerber Catena, located just west of the large crater Urvara. Troughs are common on larger planetary bodies, caused by contraction, impact stresses and the loading of the crust by large mountains — Olympus Mons on Mars is one example. The fracturing found all across Ceres’ surface indicates that similar processes may have occurred there, despite its smaller size (the average diameter of Ceres is 584 miles, or 940 kilometers). Many of the troughs and grooves on Ceres were likely formed as a result of impacts, but some appear to be tectonic, reflecting internal stresses that broke the crust.
“Why they are so prominent is not yet understood, but they are probably related to the complex crustal structure of Ceres,” said Paul Schenk, a Dawn science team member at the Lunar and Planetary Institute, Houston.
The images were taken as part of a test of Dawn’s backup framing camera. The primary framing camera, which is essentially identical, began its imaging campaign at this lowest orbit on Dec. 16. Both cameras are healthy.
Dawn’s other instruments also began their intense period of observations this month. The visible and infrared mapping spectrometer will help identify minerals by looking at how various wavelengths of light are reflected by the surface of Ceres. The gamma ray and neutron detector is also active. By measuring the energies and numbers of gamma rays and neutrons, two components of nuclear radiation, it will help scientists determine the abundances of some elements on Ceres.
Earlier in December, Dawn science team members revealed that the bright material found in such notable craters as Occator is consistent with salt — and proposed that a type of magnesium sulfate called hexahydrite may be present. A different group of Dawn scientists found that Ceres also contains ammoniated clays. Because ammonia is abundant in the outer solar system, this finding suggests that Ceres could have formed in the vicinity of Neptune and migrated inward, or formed in place with material that migrated in from the outer solar system.
“As we take the highest-resolution data ever from Ceres, we will continue to examine our hypotheses and uncover even more surprises about this mysterious world,” said Chris Russell, principal investigator of the Dawn mission, based at the University of California, Los Angeles.
Dawn is the first mission to visit a dwarf planet, and the first mission outside the Earth-moon system to orbit two distinct solar system targets. It orbited protoplanet Vesta for 14 months in 2011 and 2012, and arrived at Ceres on March 6, 2015.
Dawn’s mission is managed by the Jet Propulsion Laboratory 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, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit: http://dawn.jpl.nasa.gov/mission
More information about Dawn is available at the following sites: http://dawn.jpl.nasa.gov and http://www.nasa.gov/dawn
Dawn in Excellent Shape One Month After Ceres Arrival
Since its capture by the gravity of dwarf planet Ceres on March 6, NASA’s Dawn spacecraft has performed flawlessly, continuing to thrust with its ion engine as planned. The thrust, combined with Ceres’ gravity, is gradually guiding the spacecraft into a circular orbit around the dwarf planet. All of the spacecraft’s systems and instruments are in excellent health.
Dawn has been following its planned trajectory on the dark side of Ceres — the side facing away from the sun — since early March. After it entered orbit, the spacecraft’s momentum carried it to a higher altitude, reaching a maximum of 46,800 miles (75,400 kilometers) on March 18. Today, Dawn is about 26,000 miles (42,000 kilometers) above Ceres, descending toward the first planned science orbit, which will be 8,400 miles (13,500 kilometers) above the surface.
The next optical navigation images of Ceres will be taken on April 10 and April 14, and are expected to be available online after initial analysis by the science team. In the first of these, the dwarf planet will appear as a thin crescent, much like the images taken on March 1, but with about 1.5 times higher resolution. The April 14 images will reveal a slightly larger crescent in even greater detail. Once Dawn settles into the first science orbit on April 23, the spacecraft will begin the intensive prime science campaign.
By early May, images will improve our view of the entire surface, including the mysterious bright spots that have captured the imaginations of scientists and space enthusiasts alike. What these reflections of sunlight represent is still unknown, but closer views should help determine their nature. The regions containing the bright spots will likely not be in view for the April 10 images; it is not yet certain whether they will be in view for the April 14 set.
On May 9, Dawn will complete its first Ceres science phase and begin to spiral down to a lower orbit to observe Ceres from a closer vantage point.
Dawn previously explored the giant asteroid Vesta for 14 months, from 2011 to 2012, capturing detailed images and data about that body.
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, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit: http://dawn.jpl.nasa.gov/mission
More details about Dawn’s trajectory are available at: http://dawnblog.jpl.nasa.gov
More information about Dawn is online at: http://dawn.jpl.nasa.gov
NASA Spacecraft Becomes First to Orbit a Dwarf Planet
NASA Spacecraft Becomes First to Orbit a Dwarf Planet
Latest News From NASA’s Jet Propulsion Laboratory
NASA’s Dawn spacecraft has become the first mission to achieve orbit around a dwarf planet. The spacecraft was approximately 38,000 miles (61,000) kilometers from Ceres when it was captured by the dwarf planet’s gravity at about 4:39 a.m. PST (7:39 a.m. EST) Friday.Mission controllers at NASA’s Jet Propulsion Laboratory in Pasadena, California received a signal from the spacecraft at 5:36 a.m. PST (8:36 a.m. EST) that Dawn was healthy and thrusting with its ion engine, the indicator Dawn had entered orbit as planned. “Since its discovery in 1801, Ceres was known as a planet, then an asteroid and later a dwarf planet,” said Marc Rayman, Dawn chief engineer and mission director at JPL. “Now, after a journey of 3.1 billion miles (4.9 billion kilometers) and 7.5 years, Dawn calls Ceres, home.”
In addition to being the first spacecraft to visit a dwarf planet, Dawn also has the distinction of being the first mission to orbit two extraterrestrial targets. From 2011 to 2012, the space-craft explored the giant asteroid Vesta, delivering new insights and thousands of images from that distant world. Ceres and Vesta are the two most massive residents of our solar system’s main asteroid belt between Mars and Jupiter.
The most recent images received from the spacecraft, taken on March 1, show Ceres as a crescent, mostly in shadow because the spacecraft’s trajectory put it on a side of Ceres that faces away from the sun until mid-April. When Dawn emerges from Ceres’ dark side, it will deliver ever-sharper images as it spirals to lower orbits around the planet.
“We feel exhilarated,” said Chris Russell, principal investigator of the Dawn mission at the University of California, Los Angeles (UCLA). “We have much to do over the next year and a half, but we are now on station with ample reserves, and a robust plan to obtain our science objectives.”
Dawn’s mission is managed by JPL 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, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.
For a complete list of mission participants, visit:
http://dawn.jpl.nasa.gov/mission
For more information about Dawn, visit:
Dawn Spacecraft Begins Approach to Dwarf Planet Ceres
• Dawn has entered its approach phase toward Ceres
• The spacecraft will arrive at Ceres on March 6, 2015
PRESS RELEASE (NASA/JPL) – NASA’s Dawn spacecraft has entered an approach phase in which it will continue to close in on Ceres, a Texas-sized dwarf planet never before visited by a spacecraft. Dawn launched in 2007 and is scheduled to enter Ceres orbit in March 2015.
Dawn recently emerged from solar conjunction, in which the spacecraft is on the opposite side of the sun, limiting communication with antennas on Earth. Now that Dawn can reliably communicate with Earth again, mission controllers have programmed the maneuvers necessary for the next stage of the rendezvous, which they label the Ceres approach phase. Dawn is currently 400,000 miles (640,000 kilometers) from Ceres, approaching it at around 450 miles per hour (725 kilometers per hour).
The spacecraft’s arrival at Ceres will mark the first time that a spacecraft has ever orbited two solar system targets. Dawn previously explored the protoplanet Vesta for 14 months, from 2011 to 2012, capturing detailed images and data about that body.
“Ceres is almost a complete mystery to us,” said Christopher Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles. “Ceres, unlike Vesta, has no meteorites linked to it to help reveal its secrets. All we can predict with confidence is that we will be surprised.”
The two planetary bodies are thought to be different in a few important ways. Ceres may have formed later than Vesta, and with a cooler interior. Current evidence suggests that Vesta only retained a small amount of water because it formed earlier, when radioactive material was more abundant, which would have produced more heat. Ceres, in contrast, has a thick ice mantle and may even have an ocean beneath its icy crust.
Ceres, with an average diameter of 590 miles (950 kilometers), is also the largest body in the asteroid belt, the strip of solar system real estate between Mars and Jupiter. By comparison, Vesta has an average diameter of 326 miles (525 kilometers), and is the second most massive body in the belt.
The spacecraft uses ion propulsion to traverse space far more efficiently than if it used chemical propulsion. In an ion propulsion engine, an electrical charge is applied to xenon gas, and charged metal grids accelerate the xenon particles out of the thruster. These particles push back on the thruster as they exit, creating a reaction force that propels the spacecraft. Dawn has now completed five years of accumulated thrust time, far more than any other spacecraft.
“Orbiting both Vesta and Ceres would be truly impossible with conventional propulsion. Thanks to ion propulsion, we’re about to make history as the first spaceship ever to orbit two unexplored alien worlds,” said Marc Rayman, Dawn’s chief engineer and mission director, based at NASA’s Jet Propulsion Laboratory in Pasadena, California.
The next couple of months promise continually improving views of Ceres, prior to Dawn’s arrival. By the end of January, the spacecraft’s images and other data will be the best ever taken of the dwarf planet.
The Dawn mission to Vesta and Ceres is managed by JPL, a division of the California Institute of Technology in Pasadena, for NASA’s Science Mission Directorate, Washington. UCLA is responsible for overall Dawn mission science.
More information about Dawn:
http://dawn.jpl.nasa.gov
Media Contact
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
Elizabeth.Landau@jpl.nasa.gov
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Cosmology & Space Research Institute 
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