Beagle 2 was anticipated to land in Isidis Planitia on 25 December 2003. Less than half an hour after scheduled touchdown, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) acquired a wide angle view of the landing site. It was hoped by the MOC team that some evidence of the lander's passage through the atmosphere would be seen. That image was released on the MGS MOC web site on 31 December 2003. Like subsequent wide angle images obtained during the landings of the two Mars Exploration Rovers (e.g., Spirit), there was no visible atmospheric descent contrail or plume.
As the next several days passed without a signal from Beagle 2, the MGS MOC team, in consultation with the Beagle 2 team, began a search for the lander. The Beagle 2 team projected the highest probability landing ellipse in Isidis Planitia, and that information was made available to the MOC operations team. In other words, Beagle 2 was expected to have landed within a very specific zone. That area is shown below in Figure MOC2-835a.
Prior to landing, there were no MOC images of the final landing ellipse. The final ellipse was a bit further north than originally planned, thus all of the MOC coverage obtained before the landing was concentrated in an area outside the final ellipse. Thus, it would not be possible to compare a "before and after" view of the site where Beagle 2 had landed. The first opportunity to acquire an image of a portion of the ellipse occurred on 5 January 2004, as shown in Figure MOC2-835a and released on 30 January 2004. The ellipse in Figure MOC2-835a is drawn over a base map constructed from Mars Odyssey THEMIS Visible and Infrared images that were available at the time of landing.
MOC2-835a: Beagle 2 December 25, 2003, landing ellipse (links to 30 January 2004 release about 5 January 2004 MOC image).
NASA/JPL/Malin Space Science Systems |
Subsequent MOC imaging of the Beagle 2 landing site focused on the eastern half of the ellipse. The Beagle 2 team's decision to request that MOC concentrate its limited imaging opportunities on the eastern half of the ellipse was based on knowledge of the conditions of the martian atmosphere that came up during the period in which all three landers--Beagle 2, Spirit, and Opportunity--reached the planet. In December 2003, large dust storms had altered the temperature and pressure conditions of the atmosphere, and this ultimately resulted in the two Mars Exploration Rovers landing downrange (east) of the centers of their landing ellipses. Beagle 2, also, might have landed east of the ellipse center.
Figure MOC2-835b shows the MOC narrow angle camera coverage, acquired at full resolution of 1.5 m/pixel, obtained during the lander search campaign in January through April 2004. The 2 km scale bar is about 1.2 miles long. Slightly more than 36% of the total ellipse, and 72% of the east half of the ellipse, has been covered by MOC. Raw, cosmetically-cleaned, and map-projected versions of each MOC image were provided to the Beagle 2 team for evaluation. MOC scientists at Malin Space Science Systems also examined the images for evidence of Beagle 2, it parachute, or other hardware.
Based on their experience with searches for previous landed vehicles (Viking 1, Mars Pathfinder, Mars Polar Lander, MER-A (Spirit), and MER-B (Opportunity)), and their knowledge of the characteristics of the MOC imaging system, only one reasonably-likely candidate for Beagle 2 was identified. That candidate is indicated in Figure MOC2-835b by an arrow. The candidate is a small, dark spot located immediately west of the largest meteor impact crater in the Beagle 2 ellipse, at 11.7°N, 269.4°W. The dark spot suggested that perhaps Beagle 2 had crashed at this location. However, the dark spot is about 20 meters (~65 ft.) across, a bit larger than might be created by a crashed lander of Beagle 2's size.
MOC2-835b: East half of Beagle 2 landing ellipse, showing main MOC search area. Arrow indicates candidate "crash" site found by MOC. View at 12 m/pixel (5.2 MB) -- View at 6 m/pixel (10.4 MB) -- View at 3 m/pixel (31.4 MB) NASA/JPL/Malin Space Science Systems |
The next step in the search for Beagle 2 was to acquire an image of the dark spot with the very highest resolution that can be obtained using the MGS MOC system. MOC was designed to obtain images of resolutions as high as 1.4 to 1.5 meters per pixel (5 feet per pixel). However, during 2003 and 2004, the MOC and MGS operations teams have been developing and testing a technique whereby images of 50 centimeters per pixel in the downtrack direction (still 1.5 m/pixel crosstrack) can be acquired. This technique, known as cPROTO (compensated Pitch and Roll Targeted Observation), was used with terrific success to find the Viking 1 and Mars Pathfinder landers, and the Mars Exploration Rovers, Spirit and Opportunity.
Because the cPROTO technique is still new, it took two tries before MOC hit the candidate Beagle 2 site. Figure MOC2-835c shows a comparison of the results obtained from the normal, 1.5 m/pixel view in which the candidate site was found (left), and the cPROTO obtained with 50 cm/pixel resolution in April 2004 (right). With the higher spatial resolution obtained by the cPROTO, it became clear that the candidate Beagle 2 "crash" site was really just a small, eroded meteor impact crater with a dark patch of sand on its northern floor.
MOC2-835c: Candidate "crash" site viewed at 1.5 m/pixel (the original MOC image of the spot) and at 0.5 m/pixel in later MOC cPROTO image. View at 50% original size (3.4 MB) -- View at full size (5.2 MB) NASA/JPL/Malin Space Science Systems |
The full cPROTO image of the Beagle 2 candidate site is shown in Figure MOC2-835d. This image has been map-projected at 50 cm/pixel scale and is 3 km (1.9 mi) wide (north is up and the dark bars result from data loss upon transmission). The white arrow indicates the location of the dark candidate Beagle 2 site, which turned out to be a small, degraded impact crater and windblown sand.
MOC2-835d: The full MOC cPROTO image acquired in April 2004 to examine the candidate "crash" site. View at 3 m/pixel (3.4 MB) -- View at full size, 50 cm/pixel (36.6MB) NASA/JPL/Malin Space Science Systems |
Based on the MGS MOC imaging campaign and subsequent analyses, no incontrovertible evidence of the Beagle 2 lander was found within the areas imaged by MOC. While the period of intense searching by MOC has ended, the landing ellipse will remain a MOC target, indefinitely, until either the ellipse is covered or the MGS MOC mission ends, whichever comes first. At present, MOC is expected to continue observing Mars into late 2006, and the MOC team hopes, because of the science benefits anticipated, that another mission extension will be possible beyond 2006.
All MOC narrow angle images shown here are illuminated from the left/lower left and oriented such that north is up and east is to the right. MOC images and text describing the search for Beagle 2 by MGS MOC were included in the final report of the Beagle 2 team, released on 24 August 2004. For more information about Beagle 2 and the team's reports, visit http://www.beagle2.com/.
Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, California. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, California and Denver, Colorado.
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