The Dawn spacecraft continues to move towards a close orbit of Ceres, the largest object in the asteroid belt. (See recent report here on Dawn’s status.)  The spacecraft has not yet begun making new images of the dwarf planet. Here is a report on analysis of the planet’s surface using imaging data obtained on the approach to Ceres.

Dawn’s Ceres Color Map Reveals Surface Diversity

A new color map of dwarf planet Ceres, which NASA’s Dawn spacecraft has been orbiting since March, reveals the diversity of the surface of this planetary body. Differences in morphology and color across the surface suggest Ceres was once an active body, Dawn researchers said today at the 2015 General Assembly of the European Geosciences Union in Vienna.

This map-projected view of Ceres was created from images taken by NASA’s Dawn spacecraft during its initial approach to the dwarf planet, prior to being captured into orbit in March 2015.

The map is an enhanced color view that offers an expanded range of the colors visible to human eyes. Scientists use this technique in order to highlight subtle color differences across Ceres. This can provide valuable insights into the physical properties and composition of materials on the surface. For example, scientists have not established clear connections between impact craters and the different colors visible here, but they are investigating this possibility.

Images taken using blue (440 nanometers), green (550 nanometers) and infrared (920 nanometers) spectral filters were combined to create the map. The filters were assigned to color channels in reverse order, compared to natural color; in other words, the short-wavelength blue images were assigned to the red color channel and the long-wavelength infrared images are assigned to the blue color channel.

“This dwarf planet was not just an inert rock throughout its history. It was active, with processes that resulted in different materials in different regions. We are beginning to capture that diversity in our color images,” said Chris Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles.

The Dawn mission made history on March 6 as the first spacecraft to reach a dwarf planet, and the first spacecraft to orbit two extraterrestrial targets. Previously, Dawn studied giant asteroid Vesta from 2011 to 2012, uncovering numerous insights about its geology and history. While Vesta is a dry body, Ceres is believed to be 25 percent water ice by mass. By comparing Vesta and Ceres, scientists hope to gain a better understanding of the formation of the solar system.

Ceres’ surface is heavily cratered, as expected, but appears to have fewer large craters than scientists anticipated. It also has a pair of very bright neighboring spots in its northern hemisphere. More detail will emerge after the spacecraft begins its first intensive science phase on April 23, from a distance of 8,400 miles (13,500 kilometers) from the surface, said Martin Hoffmann, investigator on the Dawn framing camera team, based at the Max Planck Institute for Solar System Research, Göttingen, Germany.

The visible and infrared mapping spectrometer (VIR), an imaging spectrometer that examines Ceres in visible and infrared light, has been examining the relative temperatures of features on Ceres’ surface. Preliminary examination suggests that different bright regions on Ceres’ surface behave differently, said Federico Tosi, investigator from the VIR instrument team at the Institute for Space Astrophysics and Planetology, and the Italian National Institute for Astrophysics, Rome.

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.

VIR has been examining the relative temperatures of features on Ceres’ surface. Preliminary examination suggests that region 1 is cooler than the rest of Ceres’ surface, but region 5 appears to be located in a region that is similar in temperature to its surroundings.

Based on observations from NASA’s Hubble Space Telescope, planetary scientists have identified 10 bright regions on Ceres’ surface. One pair of bright spots, by far the brightest visible marks on Ceres, appears to be located in a region that is similar in temperature to its surroundings. But a different bright feature corresponds to a region that is cooler than the rest of Ceres’ surface.

The origins of Ceres’ bright spots, which have captivated the attention of scientists and the public alike, remain unknown. It appears the brightest pair is located in a crater 57 miles (92 kilometers) wide. As Dawn gets closer to the surface of Ceres, better-resolution images will become available.

“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 said.

Both Vesta and Ceres are located in the main asteroid belt between Mars and Jupiter. The Dawn spacecraft will continue studying Ceres through June 2016.

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: dawn.jpl.nasa.gov/mission/

For more information about Dawn, visit: dawn.jpl.nasa.gov

We’ll soon see closeups of the big asteroid, or dwarf planet, Ceres:

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.

Artist’s concept of Dawn above Ceres around the time it was captured into orbit by the dwarf planet in early March. Since its arrival, the spacecraft turned around to point the blue glow of its ion engine in the opposite direction. Image credit: NASA/JPL

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: dawn.jpl.nasa.gov/mission

More details about Dawn’s trajectory are available at: dawnblog.jpl.nasa.gov

More information about Dawn is online at: dawn.jpl.nasa.gov

In case you have been wondering why there have not been any images lately from the Dawn probe of the Ceres asteroid (or dwarf planet as it is now categorized) and those two bright spots on the objects surface, it is because the probe shot past the object and has been far behind Ceres. Seen it could only see Ceres’ night side, no imaging has been done. The planned trajectory has it coming back into orbit around Ceres later this month.

Here is an overview of the status of the mission: Dawn Journal: Preparing to Photograph Ceres – The Planetary Society

The trajectory of Dawn as it goes past Ceres and then loops back.

—

The European Space Agency’s Asteroid Impact Mission (AIM) will visit a pair of asteroids for scientific exploration and also to investigate issues regarding the defense of earth from asteroid impacts: ESA’s planetary defence test set for 2020 – ESA

ESA’s Asteroid Impact Mission, or AIM. Intended to demonstrate technologies for future deep-space missions, AIM will also be the Agency’s very first investigation of planetary defence techniques.

Launched in October 2020, AIM will travel to a binary asteroid system – the paired Didymos asteroids, which will come a comparatively close 11 million km to Earth in 2022. The 800 m-diameter main body is orbited by a 170 m moon, informally called ‘Didymoon’.

This smaller body is AIM’s focus: the spacecraft will perform high-resolution visual, thermal and radar mapping of the moon to build detailed maps of its surface and interior structure. 

Two years after AIM reaches Didymos, NASA’s DART (Double Asteroid Redirection Test) spacecraft will collide into the smaller of the two asteroids while AIM observes the amount of deflection of the asteroid and the effects of the collision on the surface structure of the asteroid. This joint mission is called the Asteroid Impact & Deflection Assessment (AIDA) study:

—

* Dr. Bruce Damer, Tuesday, 3-31-15 – Thespaceshow’s Blog – Dr. Bruce Damer of DigitalSpace talked with David Livingston on the Space Show about a paper with several co-authors on a concept of capturing a small asteroid for NASA’s Asteroid Re-Direct Mission (ARM) within a sealed abd gas filled bag:

A sealed enclosure would make it possible to use an introduced atmosphere of xenon gas to detumble and despin the asteroid, and then to push the asteroid by using a steady xenon gas flow inside this enclosure to transfer the force of the spacecraft’s exterior solar electric propulsion engine to the asteroid.

The paper is available online at SHEPHERD: A Concept for Gentle Asteroid Retrieval with a Gas-Filled Enclosure.

Here is the interview:

Large version (649K)