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Knowing precisely where a spacecraft lands on Mars is important for understanding the regional and local context, setting, and the offset between the inertial and cartographic frames. For the InSight spacecraft, the payload of geophysical and environmental sensors also particularly benefits from knowing exactly where the instruments are located. A ~30 cm/pixel image acquired from orbit after landing clearly resolves the lander and the large circular solar panels. This image was carefully georeferenced to a hierarchically generated and coregistered set of decreasing resolution orthoimages and digital elevation models to the established positive east, planetocentric coordinate system. The lander is located at 4.502384°N, 135.623447°E at an elevation of -2,613.426 m with respect to the geoid in Elysium Planitia. Instrument locations (and the magnetometer orientation) are derived by transforming from Instrument Deployment Arm, spacecraft mechanical, and site frames into the cartographic frame. A viewshed created from 1.5 m above the lander and the high-resolution orbital digital elevation model shows the lander is on a shallow regional slope down to the east that reveals crater rims on the east horizon ~400 m and 2.4 km away. A slope up to the north limits the horizon to about 50 m away where three rocks and an eolian bedform are visible on the rim of a degraded crater rim. Azimuths to rocks and craters identified in both surface panoramas and high-resolution orbital images reveal that north in the site frame and the cartographic frame are the same (within 1°).
RESUMO
The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft landed successfully on Mars and imaged the surface to characterize the surficial geology. Here we report on the geology and subsurface structure of the landing site to aid in situ geophysical investigations. InSight landed in a degraded impact crater in Elysium Planitia on a smooth sandy, granule- and pebble-rich surface with few rocks. Superposed impact craters are common and eolian bedforms are sparse. During landing, pulsed retrorockets modified the surface to reveal a near surface stratigraphy of surficial dust, over thin unconsolidated sand, underlain by a variable thickness duricrust, with poorly sorted, unconsolidated sand with rocks beneath. Impact, eolian, and mass wasting processes have dominantly modified the surface. Surface observations are consistent with expectations made from remote sensing data prior to landing indicating a surface composed of an impact-fragmented regolith overlying basaltic lava flows.
RESUMO
SETTING: The DOTS strategy was introduced in El Salvador in 1997 and had become fully implemented countrywide by 2001. Previously, many deficiencies were identified in the management of patients with tuberculosis (TB). OBJECTIVE: To ascertain the prevalence of Mycobacterium tuberculosis resistant to first-line drugs. DESIGN: A national prospective survey was carried out in 2001 using the standardised World Health Organization/ International Union Against Tuberculosis and Lung Disease model. RESULTS: A total of 711 cultures were analysed (59% of total smear-positive cases); 611 were never treated and 100 were previously treated patients. The study showed resistance rates to isoniazid and rifampicin, either alone or combined (multidrug resistance, MDR), of 1.3%, 1.1% and 0.3%, respectively, in never treated patients, and 12%, 13% and 7%, respectively, in previously treated patients. CONCLUSION: The low rates of MDR-TB in El Salvador are puzzling, as out-patient DOTS was introduced only recently and fixed-dose combination tablets have not been used.