NEAR Orbit Around Asteroid 433 Eros

Images of Eros

[NEAR image of asteroid Eros] A Hint of Structure

This is a mosaic of four images taken by NEAR Shoemaker on September 5, 2000, from about 100 kilometers (62 miles) above Eros. The knobs sticking out of the surface near the top of the image surround a boulder-strewn area (featured as the Image of the Day for April 4, 2000) and are probably remnants of ancient impact craters. The very faint grooves that run diagonally across the surface in this image may have formed during a collision between the asteroid and a smaller body. (Mosaic of images 0143581726, 0143581602, 0143581788, 0143581664)

[NEAR image of asteroid Eros] Flat and Smooth

NEAR Shoemaker obtained the two images in this mosaic on September 16, 2000, from a vantage point 100 kilometers (62 miles) above Eros. This view shows one of the asteroid's ends, and is interesting because the area appears very flat and smooth, with few impact craters. The largest craters (one just left of center and another at bottom right) have degraded to where they no longer have rims, which implies that they are relatively old. The shallow concave area in the upper middle of the mosaic is the outline of the boulder-strewn region highlighted on April 4, 2000. (Mosaic of images 144528837, 144528713)

[NEAR image of asteroid Eros] Brightness Variations in the Saddle

This montage of NEAR Shoemaker images, taken September 5, 2000, from an orbital altitude of 100 kilometers (62 miles), shows the north equatorial region of Eros' saddle. This region is known to exhibit brightness mottling, which may come from exposure of regolith less darkened by the space environment. In this spectacular view, the western part of the saddle faces the Sun, highlighting brightness variations in the surface materials. This type of lighting also minimizes shading variations. (Mosaic of images 0143581009, 0143581071, 0143581133, 0143581195)

[NEAR image of asteroid Eros] Square Craters

Craters generally tend to be round, but this image shows some craters that are more square than round. The likely reason for this is that Eros had some fractures (known as structural features) at its surface that were present before the impact events that formed the craters. These fractures can be seen in the lower part of the top crater. When the impacts that formed these craters occurred, the resulting crater cavities were influenced by the fractures. The result is that the crater rims that run parallel to the fractures are straighter than craters located in nonfractured areas. Geologists call this kind of effect on the craters "structural control", and a similar occurrence can be seen on Earth at Arizona's Barringer Meteor crater, which also has a slightly squared-off shape to its rim. Note also the boulder perched just beyond the right hand rim of the top crater that looks like a bright speck in the image. The shape of the boulder can be seen by its shadow, which is cast onto the crater floor. The shadow shows that the boulder is diamond shaped, and it appears to be standing on one tip. This image was taken on April 26, 2000, when NEAR Shoemaker was 50 kilometers above the surface. (Image 132151598)

[NEAR image of asteroid Eros] Under the Saddle

NEAR Shoemaker took the four images in this mosaic on September 9, 2000, from an altitude of about 100 kilometers (62 miles). NEAR Shoemaker's current orbit affords a global look at Eros much like earlier in the mission, but from a more southerly perspective. The top of this mosaic shows Eros' saddle, and curving around at upper right is the large bright-and-dark groove (featured on May 9 and June 2 ). The bright curved feature is a broad topographic rise separating the saddle region from the most boulder-rich area on the asteroid (featured April 4). (Images 143707341, 143707256, 143707426, 143707511)

[NEAR image of asteroid Eros] Looking Along the Southern Hemisphere

The camera on NEAR Shoemaker caught this long view of Eros' southern hemisphere during a stereo imaging sequence on September 6, 2000, from an orbital altitude of 101 kilometers (63 miles). This view adds context to high-resolution images taken from lower orbits with "footprints" only one-fourth to one-third the size. Craters shown in the left foreground of the image are about 1.3 kilometers (0.8 miles) across. (Image 0143688711)

[NEAR image of asteroid Eros] Inside the Paw, Part I

NEAR Shoemaker's camera caught this crater -- nicknamed "the paw" -- during a color imaging sequence on September 2, 2000, from an orbital altitude of 51 kilometers (32 miles). Several smaller craters superimposed on the southern rim of the large, 5.3-kilometer (3.3-mile) diameter impact crater help create a shape that resembles a giant animal footprint, thus the nickname. The bright material is believed to be relatively freshly exposed regolith uncovered after surface material slid down the crater wall. It appears brighter because it has not been exposed to the space environment for as long as the darker areas around it. The whole scene is 1.4 kilometers (0.9 miles) across. (Image 0143336637)

[NEAR image of asteroid Eros] Long Groove, Nice View

This view of a long groove on Eros was captured by NEAR Shoemaker's camera during an imaging sequence taken on September 1, 2000, from an orbital altitude of 83 kilometers (52 miles). The groove that cuts across the top of the image is 140 meters (460 feet) across but only a few meters deep. It is easily visible here only because it is so obliquely illuminated that the subtle topography stands out. Grooves are thought to have formed over deep fractures in the asteroid, possibly where loose regolith has drained into the cracks. This particular groove appears to be relatively old because a rather large 400-meter (1300-foot) diameter impact crater (seen in the upper right of the image) has been superimposed on it. The whole scene shown here is 2.7 kilometers (1.7 miles) across. (Image 0143180389)

[NEAR image of asteroid Eros] Mapping Eros

The camera on NEAR Shoemaker took this picture of a section on Eros' southern hemisphere on August 30, 2000, from an orbital altitude of 97 kilometers (60 miles). One of the mission objectives at this altitude is to cover the southern hemisphere taking images that look straight down onto the surface, as in this image. For cartography - that is, making maps - this kind of geometry is favored because it results in minimal distortion of surface features. The scene shown in this image is 4.1 kilometers (2.5 miles) across. (Image 0143008782)

[NEAR image of asteroid Eros] Big Old Crater

On August 28, 2000, the camera on NEAR Shoemaker took this picture of Eros' limb from an orbital altitude of 100 kilometers (62 miles). The two craters near the top left part of the frame are about 2.2 kilometers and 1.6 kilometers (1.4 miles and 1 mile) in diameter, respectively. The top large crater is thought to be relatively old because many smaller craters have been superimposed on its rim and interior--an indication that it has been subjected to a very long period of bombardment by impacting meteors. The whole scene is about 3 kilometers (1.8 miles) across. (Image 0142855427)

[NEAR image of asteroid Eros] Sentinels

This NEAR Shoemaker picture, taken August 6, 2000, from an orbital altitude of 49 kilometers (30 miles), shows Eros' horizon near the time of local sunset. The surface is dark because of the oblique illumination, but several boulders catch the sunlight and appear like bright sentinels on the landscape. The brightest of the boulders, just to the upper right of the deeply shadowed crater in the foreground, is about 30 meters (100 feet) across. The whole scene is about 2.2 kilometers (1.4 miles) across. (Image 0140941905)

[NEAR image of asteroid Eros] Starting with a Clean Slate

One of the surprising findings about Eros is the extent to which geologic activity has wiped out ancient craters on parts of the asteroid's surface. This picture, taken with NEAR Shoemaker's digital camera on August 5, 2000, from an orbital altitude of 52 kilometers (32 miles), shows part of the "saddle" region, in which many craters have been obliterated. Only two curved rim segments remain of the large crater in the right-middle part of the image. The whole scene is about 2.2 kilometers (1.4 miles) across. (Image 0140881190)

[NEAR image of asteroid Eros] Inside the Paw

This image, taken August 5, 2000, from an orbital altitude of 49 kilometers (30 miles), shows the inside wall of "the paw," the large, 5.3-kilometer (3.3-mile) diameter crater that dominates Eros' western hemisphere. Here the local contrasts in brightness of surface material are among the most dramatic on the asteroid. Bright, relatively newly exposed regolith has streamed slowly downslope to form tongue-like shapes that meet older, darker regolith exposed to the effects of solar wind and micrometeorite impacts. The whole scene is about 1.4 kilometers (0.9 miles) across. (Image 0140836452)

[NEAR image of asteroid Eros] Tracks

Some regions of Eros, like any other planetary body, pack a lot of rich geologic detail into small spaces. On Earth, for example, the Alps, Himalayas or Rockies hold "records" that show how the Earth works as a planet, and match those key features with scenes of beauty that capture the imagination. This NEAR Shoemaker picture, taken August 4, 2000, from an orbital altitude of 49 kilometers (30 miles), provides a wealth of information on Eros. The boulders near the center of the frame have intricate shapes that may indicate what causes Eros to fracture and break apart in a particular way. The oblong crater in the upper right of the frame has a bright ring in its interior wall that may hold information about subsurface properties. And the many small, smooth patches show that, very locally, some process either erases craters or resists their formation. At the same time the landscape provokes the imagination: the group of craters just to the right of the cluster of rocks bears an uncanny resemblance to a giant footprint or track. The whole scene is about 1.8 kilometers (1.1 miles) across. (Image 0140824679)

[NEAR image of asteroid Eros] Rocky Hollow Picture Show

NEAR Shoemaker images of Eros' saddle region show landscapes that couldn't differ more from what one might have expected for an ancient, crater-battered body. Early images of the northern part of the saddle stunned mission scientists with their abundance of boulders and lack of craters. Recent images of the southern part of the saddle, now well illuminated having emerged from the southern hemisphere's long night, continue this fascinating picture show. This picture, taken August 3, 2000, from an orbital altitude of 50 kilometers (31 miles), shows a region about 1.4 kilometers (0.9 miles) across. Boulders as small as 8 meters (26 feet) across are visible. In this part of the saddle, small patches of brighter regolith also occur among the rocks. (Image 0140695586)

[NEAR image of asteroid Eros] The Impact of Cratering

Impacts to Eros slowly and continually modify the appearance of the asteroid's surface. This NEAR Shoemaker image taken July 23, 2000, from an orbital altitude of 38 kilometers (24 miles), shows the effects around a crater that is nearly a mile (1.6 kilometers) across. An impact excavated a huge gouge, and caused some of the excavated material to form a thin cover on parts of Eros. The fastest-moving fraction of the crater's ejecta (traveling at more than several meters per second) escaped Eros, whereas slower-moving material eventually returned to the surface. The boulders in the foreground, about 15 meters (50 feet) across, are typical of the largest pieces in a crater's ejecta. Over time the surface layer slid off the crater's walls to expose brighter material from below, which has not yet been darkened by space weathering. The picture shows a region about 1 kilometer (0.6 miles) across. (Image 0139411864)

[NEAR image of asteroid Eros] A Lacework Surface

With the Sun high in Eros' sky, shadows disappear and bright surface features stand out. In this picture taken by NEAR Shoemaker on July 19, 2000, from an orbital altitude of 36 kilometers (22 miles), the Sun is nearly overhead. The steep local slopes are hard to see without shadows, but the lacework of bright and dark regolith is at its most conspicuous. The image shows a region about 800 meters (2,600 feet) across. The smallest visible rocks are about 6 meters (19 feet) across. (Image 0139411864)

[NEAR image of asteroid Eros] Eros' Littered Surface from Low Altitude

NEAR Shoemaker's incredibly detailed images from the low orbit around Eros continue to surpass the expectations of the mission team. This picture, taken July 24, 2000, from an orbital altitude of 36 kilometers (22 miles), shows a region about 900 meters (3,000 feet) across. Some of the largest boulders in the scene, such as the broken one at the upper left, show angular shapes. Many smaller boulders litter the scene; the smallest ones visible here are about 6 meters (19 feet) across.

Regolith seems to have banked up against several rocks. In some places, like the large crater below the center of the picture, regolith also appears to have filled, or "ponded," in low spots. (Image 0139820288)

[NEAR image of asteroid Eros] Sandy Impressions

Though it looks like raindrop impressions on a sandy beach, this image is actually a section of asteroid Eros that has an abundance of large, smoothed craters and a deficit of small craters. The pattern of impressions gives us clues to Eros' geologic history. The relative lack of small craters -- which should be far more abundant -- suggests that a resurfacing of this part of the asteroid has buried or removed the small craters.

The picture was taken July 12, 2000, from an orbital altitude of 46 kilometers (29 miles), and shows a region about 1.6 kilometers (1 mile) across. (Image 0138807458)

[NEAR image of asteroid Eros] Shapes Galore

Exploration of small asteroids by spacecraft and ground-based radar has shown that these tiny worlds come in many sizes and shapes. This NEAR Shoemaker image, taken July 12, 2000, from an orbital altitude of 38 kilometers (24 miles), brings home the irregularity of the tiny little world called Eros. Looking down the length of the asteroid, one sees near, middle, and far horizons. The whole scene is about 0.9 kilometers (0.5 miles) across. (Image 0138776896)

[NEAR image of asteroid Eros] The Battering and Debris

The many craters on Eros' surface attest to its battering by meteors - mostly debris ejected from other asteroids. This picture, taken July 7, 2000, from an orbital altitude of 50 kilometers (31 miles), neatly encapsulates the effects of a long history of impact cratering. Two overlapping craters, probably formed many millions of years apart, form a composite depression nearly 1.6 kilometers (1 mile) long. Large boulders, perhaps broken off Eros during these impacts, are perched on the craters' edge. The largest boulder, on the horizon in the center of the picture, is about 40 meters (130 feet) long. The whole scene is 1.8 kilometers (1.2 miles) across. (Image 0138353656)

[NEAR image of asteroid Eros] The Color of Regolith

On June 14, 2000, NEAR Shoemaker trained its camera on Eros' large, 5.3-kilometer (3.3-mile) diameter crater for a series of color pictures intended to measure the properties of regolith inside the asteroid's craters. In this false color view -- taken from an altitude of 50 kilometers (31 miles) -- redder hues represent rock and regolith that have been altered chemically by exposure to the solar wind and small impacts. Bluer hues represent fresher, less-altered rock and regolith, such as the bright patches that have been less affected by "space weathering." In that process, during micrometeorite impacts, rock reacts with miniscule amounts of trapped solar wind and is chemically changed. Interestingly, most of the large boulders have been just as affected as the regolith. This suggests either that the rocks are relatively old, or that they are "dirty" from an adhering film of regolith particles. (Composite of images 0136359580, 0136359582, 0136359584)

[NEAR image of asteroid Eros] Southwest of the Big Crater

This mosaic of eight images -- which NEAR Shoemaker snapped on May 14, 2000, from an altitude of 50 kilometers (31 miles) -- covers the region southwest of Eros' large, 5.3-kilometer (3.3-mile) diameter crater. The bright patches at upper right are relatively freshly exposed regolith on the inside wall of the crater. The two large, subdued craters in the center of the mosaic are each about 1 kilometer (0.6 miles) wide. The boulder on the floor of the crater to the left is one of the larger rocks on Eros, more than 90 meters (295 feet) across. The whole scene is about 4 kilometers (2.5 miles) across. (Mosaic of images 0133697893, 0133698083, 0133698273, 0133698463, 0133698653, 0133698843, 0133699033, 0133699223)

[NEAR image of asteroid Eros] The Wall

This picture of Eros, taken from NEAR Shoemaker on June 20, 2000, shows a stunning aspect of the "bent" asteroid's peanut-like shape. The far side of the asteroid looms like an enormous wall beyond a near horizon in the foreground. The image was taken from an altitude of 51 kilometers (32 miles) and shows a region about 1.4 kilometers (0.9 miles) across. (Image 0136395694)

[NEAR image of asteroid Eros] Rock Overhang

NEAR Shoemaker focused on a group of large boulders on Eros' horizon for this picture, taken on June 19, 2000, from an altitude of 51 kilometers (32 miles). One of the boulders (marked by the arrow) is about 30 meters (98 feet) high and has a large overhang on its right side. The right-hand tip of the boulder is about 10 meters (33 feet) off the ground, providing a space under the overhang large enough to park a tractor-trailer truck. The whole scene is approximately 1.9 kilometers (1.2 miles) across. (Image 0136823869)

[NEAR image of asteroid Eros] Peeking into the Sunlight

NEAR Shoemaker images have shown many large boulders on Eros' surface, but seldom are the boulders as big and as close as the ones in this image taken on June 20, 2000, from an altitude of 51 kilometers (32 miles). Nestled within the 700-meter (2300-foot) diameter crater at the center of the picture are four particularly large rocks whose tops protrude out from the shadowed crater interior and into sunlight. The center boulder, the largest, is about 100 meters (330 feet) across. The whole scene is approximately 1.9 kilometers (1.2 miles) across. (Image 0136819148)

[NEAR image of asteroid Eros] A Swath of Eros

NEAR Shoemaker's scientific observations of Eros focus on different priorities as the spacecraft descends into lower orbits. For example, during the 100-kilometer (62-mile) orbit from April 11 - 22, 2000, the camera's mission was to build a global photomosaic under optimal viewing conditions. Due to the asteroid's irregular shape, doing this required imaging Eros repeatedly until each spot had been covered just right.

This swath of images - taken April 13 as part of that mapping campaign - shows several of the asteroid's major features. From top to bottom, these include large craters in the north polar region; part of the ridge that wraps one-third of the way around Eros; the western part of the saddle; and a dense field of enormous boulders. (Mosaic of images 0131031742, 0131031827, 0131031912, 0131031997)

[NEAR image of asteroid Eros] Twin Pits

Some impact craters occurring on Earth and on other planetary bodies come in close pairs. These double craters are sometimes the result of the chance superimposition of two distinct impact events. However, a few double craters are also thought to have formed by the impact of two similarly sized bodies that are traveling in close orbit or touching each other. The near-Earth asteroid 4769 Castalia, which has been imaged by radar, is one of the most promising candidates for being such a "contact binary."

This image, taken on June 10, 2000, from an orbital altitude of 51 kilometers (32 miles), caught an obliquely illuminated view of a double crater on Eros. The two craters are so close to each other that they merge into the single dumbell-shaped depression in the center of the image. Each of the two craters is about 550 meters (1800 feet) across. The whole scene is 1.9 kilometers (1.2 miles) across. (Image 0135959925)

[NEAR image of asteroid Eros] Mosaic of Eros' Northern Hemisphere

While NEAR Shoemaker orbits Eros, the asteroid appears too large for the camera's field of view. In order to get a complete view of the surface from a particular vantage point, several images are mosaicked. To do this, the digital images returned by the spacecraft are draped over a computer model of the asteroid's shape.

This spectacular view -- looking down on the north polar region -- was constructed from six images taken February 29, 2000, from an orbital altitude of about 200 kilometers (124 miles). This vantage point highlights the major physiographic features of the northern hemisphere: the saddle seen at the bottom; the 5.3-kilometer (3.3-mile) diameter crater at the top; and a major ridge system running between the two features that spans at least one-third of the asteroid's circumference. (Mosaic of images 0127275100, 0127275164, 0127275246, 0127275310, 0127275456, 0127275520)

[NEAR image of asteroid Eros] Color View of the Saddle

Color imaging of Eros from the NEAR Shoemaker spacecraft has shown the asteroid's color variations are very subdued when compared to those of other planetary bodies, such as Mars. However, both the imager and the near-infrared spectrometer have detected discernible color differences between parts of the asteroid.

One location on Eros with distinctive color is the eastern side of the "saddle." This color composite image of that region was taken April 2, 2000, from an orbital altitude of 201 kilometers (125 miles). In this false color representation, the red and green image planes were taken in different wavelengths of infrared light, and the blue image plane was taken in blue light. NEAR scientists interpret the bright and greenish-gray appearing regions near the rim of the saddle to represent relatively fresh exposures of subsurface soil. In contrast, the pinkish looking soil covering other areas is thought to have been modified by exposure to small impacts and the solar wind. (Composite of images 130105837, 130105839, 130105841)

Captions and images courtesy of the NEAR Project (JHU/APL).
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More information on asteroid 433 Eros
Asteroid Fact Sheet
NSSDCA Asteroid Home Page

Information on the Multispectral Imager
Information on the NEAR Mission Profile and Trajectory

Images from the Eros and Mathilde Flybys
NEAR Eros Images - Applied Physics Lab, JHU

Detailed information on NEAR from the NSSDCA Master Catalog
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Dr. David R. Williams,
NSSDCA, Mail Code 690.1
NASA Goddard Space Flight Center
Greenbelt, MD 20771

NASA Official: Dr. Ed Grayzeck,
Last Updated: 18 December 2001, DRW