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Mission update 1: Mars comes into focus in this enhanced-colour view of the Terra Sirenum region of Mars. These gullies in the sides of an unnamed crater are further signs of the erosive action of water in martian geological history. This image covers an area just 250 m across, showing the potential of the HiRISE camera on NASA’s Mars Reconnaissance Orbiter. The high signal-to-noise ratio of the HiRISE camera allows colours to be distinguished in shadows, so that true albedo features can be distinguished from topographical features in dark areas. (NASA/JPL/ Univ. of Arizona) As orbiters and rovers work simultaneously on Mars, an Earth orbiter shows the way forward for planetary exploration; multiwavelength astronomy shows its power in astrophycial investigations of the oldest and most distant objects. MRO makes ready for work NASA’s Mars Reconnaissance Orbiter has made a series of observations from a low orbit, producing detailed environmental observations from the present and past martian surface (figure 1). The orbiter’s high-resolution camera, imaging spectrometer, context camera, ground-penetrating radar, atmospheric sounder, global colour camera, radio and accelerometers were being checked out on various parts of the planet’s surface before the start of the primary mission in November this year. All the instruments are working well, and the High Resolution Imaging Science Experiment (HiRISE) camera was even able to snap a picture of the rover Opportunity as it sat in Victoria Crater. http://www.nasa.gov/mission_pages/ MRO/main/index.html Dry ice and dust geysers An idea for the origin of an enigmatic area near the southern martian pole has been dismissed as a result of data A&G • December 2006 • Vol. 47 from the European Space Agency’s OMEGA instrument on Mars Express. The “cryptic region” was detected by orbiters in the 1970s, in the form of a pattern of large areas that became much darker than their surroundings in the spring. Once the temperature was measured at –135 °C, researchers knew that solid carbon dioxide was likely, and suggested that a layer of clear carbon dioxide ice might be present that would allow the dark surface below to show through. But OMEGA’s infrared observations have shown no significant carbon dioxide ice signal in the cryptic region. http://www.esa.int/SPECIALS/Mars_ Express/SEMMT0O7BTE_0.html Spitzer shows supernova The supernova that formed Cassiopeia A exploded in such a way as to keep intact much of its original onion-like layering, astronomers using NASA’s infrared Spitzer Space Telescope have discovered. The original star that exploded to form Cas A, like all mature massive stars, was once formed of concentric shells with lighter elements in the outer skin, middle layers lined with heavier elements such as neon, and the heaviest elements, such as iron, in the core. A fairly uniform explosion would send these compositional layers outwards in order, preserving the pattern in the expanding debris. Observations had shown some layering patterns, but there were mysterious gaps. Spitzer observations of X-ray emis- sions arising from expelled material heated by shock waves from the explosion solved the riddle. It turns out that parts of the Cas A star had not been shot out as fast as others when the star exploded. Material that hit the shock wave sooner had more time to heat up to temperatures that radiate X-ray and visible light. Mat erial that is just now hitting the shock wave is cooler and glowing with infrared light. Consequently, previous X-ray and visible-light observations identified hot, deep-layer material that had been flung out quickly, but not the cooler missing chunks that lagged behind. Spitzer’s infrared detectors were able to find gas and dust made from the middle-layer elements neon, oxygen and aluminum. “Spitzer has essentially found key missing pieces of the Cassiopeia A puzzle,” said Jessica Ennis of the University of Minnesota, Minneapolis, lead author of a paper in the 20 November issue of the Astrophysical Journal. http://www.spitzer.caltech.edu/spitzer Long ago and far away Astronomers have images – and detailed physical properties – of two of the most distant galaxies ever seen. Carnegie Fellow Ivo Labbé, along with Rychard Bouwens and Garth Illingworth of the UCO/Lick Observatory at the University of California, Santa Cruz, and Marijn Franx of the Leiden Observatory, examined galaxies in the Hubble Ultra Deep Field (HUDF) using the sensitive Infrared News • Mission Update Space Shorts Sensorwebs show way An Earth observation satellite has shown the effectiveness of artificial intelligence in making use of a web of sensors, in this case to start observing a newly active volcano. Earth Observer 1 began watching the Indonesian volcano Talang in September 2005 before volcanologists were asked to examine it, thanks to its intelligent response to observations. EO-1 can tap into networks of sensors on Earth, in this case the USGS volcano observatories in Hawaii, Washington and Antarctica, and is starting to use sensors on other satellites, such as the MODIS infrared spectrometers on NASA satellites Terra and Aqua, that can pick up heat from forest fires and volcanoes. In this case, EO-1 detected a volcanic plume, but it can seek out flash-floods, forest fires, disintegrating sea-ice, and anything unexpected. http://science.nasa.gov/headlines/ y2006/26oct_sensorweb. htm?list108954 Sunrise on Hinode The Solar-B satellite, a joint Japan/NASA/PPARC mission which was launched on 22 September 2006 and renamed Hinode, reported its first observations of the Sun on 31 October. Hinode is Japanese for sunrise, an appropriate name given that the mission’s target is to watch massive explosive solar flares at close quarters as they erupt from the Sun’s surface and rise into interstellar space. All three instruments are working well: the Solar Optical Telescope, the X-Ray Telescope, and the EUV Imaging Spectrometer. Researchers at University College London’s Mullard Space Science Laboratory have led work on the EIS. “Waiting for the first data from an instrument that has taken years to design and build is always a heartstopping moment,” said Prof. Len Culhane, EIS Principal Investigator. “We create incredibly sensitive detectors such as EIS, then strap them to a rocket and hurl them into space under extremely challenging conditions. Finding out that it survived and is working correctly is a huge relief because the options are very limited if it is not.” http://www.pparc.ac.uk/Nw/Stereo_ launch.asp 6.9