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| Astronomy & Geophysics 44 (4) 4.04 | | |||||
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| Lift-off for Mars missions Peter Bond surveys the missions that have set off for Mars.  Mars Express is on its way and (inset) the planned landing sites: 1 Meridiani Planum; 2 Gusev crater; 3 Isidis Planitia; 4 Mars Polar Lander. (Nature) Mars missions were grabbing the headlines in June and July as four spacecraft set off towards the Red Planet: Mars Express and Beagle 2 and NASA&Apos;s two Mars Exploration Rovers called Spirit and Opportunity. Mars Express, the European Space Agency's first planetary spacecraft, lifted off from Baikonur on 2 June and the Fregat upper stage successfully injected the 1120 kg probe into its interplanetary orbit. During subsequent spacecraft commissioning, engineers recorded an interconnection problem between the solar arrays and the power conditioning unit. This means approximately 70% of the power generated by the solar arrays is available for the satellite and its payload to use. Despite this power shortage, ESA insists that the nominal Mars observation mission will be achievable, although satellite payload operations may have to be reviewed for short periods. After about 400 million km, Mars Express will release Beagle 2 on a collision trajectory with Mars. After five days of ballistic flight, the lander will plunge into the thin martian atmosphere on Christmas Day, using a parachute and airbags during its descent to Isidis Planitia. Once its clam-like structure opens to reveal the main communications antenna, solar arrays and instruments, Beagle 2 will gather mineralogical data that should, for the first time, allow rock samples to be dated with absolute accuracy. Boasting the highest science-payload-to-systems-mass ratio of any planetary spacecraft, Beagle 2 carries a grinder-corer and a wire-guided mini-robot “mole” that can burrow under rocks. Beagle 2 has a gas analysis package, environmental sensors, a microscope, two spectrometers to investigate the composition of rocks and stereo cameras. Meanwhile, Mars Express will carry out a detailed investigation of the planet from an elliptical near-polar orbit. Its seven instruments (some based upon those lost on Mars-96) include a very-high-resolution stereo camera, spectrometers to map the planet's mineralogy and analyse the composition of the martian atmosphere, and a radar instrument to sound the surface to a depth of 2 km, exploring its structure and searching for pockets of water. Another instrument will investigate the interaction between the upper atmosphere and the interplanetary medium. The orbiter mission should last at least one martian year (687 days), while Beagle 2 is expected to operate on the planet's surface for 180 days (www.esa.int/SPECIALS/Mars_Express/index.html and www.beagle2.com). NASA&Apos;s $800 m Mars Exploration Rover project got off the ground on 10 June, when a Delta II rocket lifted off from Cape Canaveral carrying the Spirit rover. If all goes according to plan, Spirit will land in Gusev Crater, 15° south of Mars' equator, on 3 January 2004. Opportunity should touch down at Meridiani Planum, about 2° south of the equator and halfway around the planet from Gusev, on 25 January. Both rovers will reach the surface with the aid of parachutes, retro-rockets and inflated gasbags. The two landing sites were selected after a lengthy debate. Gusev is a 150 km diameter impact crater which is entered from the south east by a 900 km long meandering channel called Maadim Vallis. This valley is believed to have been eroded long ago by flowing water which subsequently filled the crater. Sediments on the crater floor may provide clues to conditions that prevailed during a previous wetter epoch. Meridiani Planum is one of the flattest, smoothest places on Mars, but its main attraction for scientists is the existence of grey haematite, a mineral that forms on Earth in the presence of liquid water (mars.jpl.nasa.gov/mer/). Peter Bond | |||
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| AstroGrid and the Astrophysical Virtual Observatory: first capabilities Nicholas Walton brings news of solid progress. AstroGrid (www.astrogrid.org) is now making rapid progress in creating the UK's Virtual Observatory. 31 March 2003 saw the delivery of its Iteration 1 release. Future iteration releases will be delivered on a three monthly basis, the next being 30 June 2003. Each iteration release will provide increased functionality for the end user. Early users of AstroGrid products will find more information at the “beta tester” pages located at wiki.astrogrid.org/bin/view/Astrogrid/BetaTesting. AstroGrid plays a major role in the European Astrophysical Virtual Observatory initiative. Its “first light” event was held at Jodrell Bank Observatory on 20 January 2003. This saw the demonstration and release of a sophisticated tool to access and manipulate deep multiwavelength data coming from the public access GOODS programme (Great Observatories Origins Deep Survey). Full details are available at www.euro-vo.org/pub/articles/avoprototype3.html. Together with its European and international partners (e.g. the USA&Apos;s National Virtual Observatory), AstroGrid is taking the lead in organizing a major demonstration of early-release Virtual Observatory capabilities at the upcoming IAU General Assembly (see www.astronomy2003.com/). The Virtual Observatory projects will be exhibiting during this event under the umbrella of the International Virtual Observatory Alliance (www.ivoa.net), and will feature demonstrations from the major VO projects. In a collaborative programme AstroGrid and the Australian-VO project will show the deployment, on the AstroGrid system, a compute-intensive volume-rendering application that will allow an astronomer to perform advanced visualization of large data cubes remotely located on the Grid. A full report of this and further developments with AstroGrid will feature in a future issue of A&G. Nicholas Walton |
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| Who wants to use the JKT? The Jacobus Kapteyn telescope on La Palma will be more widely available this year. Rene Rutten seeks expressions of interest.  The Jacobus Kapteyn Telescope: excellent facilities available to the community. The 1 m Jacobus Kapteyn Telescope at the world-class observatory site Roque de los Muchachos on the island of La Palma, Spain, will be taken out of service as a common-user facility as of August 2003. Instead, the telescope may be offered for use to paying customers. This announcement calls for expressions of interest from potentially interested parties. Expressions of interest should be sent, preferably by email, to the address below, to arrive before 5 September. You will receive an acknowledgement of receipt. Your statement should include an indication of how you expect to use the telescope (i.e. for a specific long-term scientific programme, as part of a consortium, student training etc) and how you expect to acquire funding. Note that at this stage no firm commitments are requested. Further enquiries can be directed to the same address: Dr R G M Rutten, Isaac Newton Group of Telescopes, Apartado de Correos 321, E-38700 Santa Cruz de la Palma, Spain; rgmr@ing.iac.es. Rene Rutten | |||
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This issue of A&G is unusual in that it carries a set of papers around just one theme: Mars. In part this reflects the close approach of the planet to Earth, celebrated in National Astronomy Week, which means that the planets will be especially visible, to both astronomers at work and those who watch the skies at rest, or at play. The close approach also means a flurry of missions to the Red Planet, taking advantage of the conjunction. Among them will be Beagle 2, a British-led lander, aboard Mars Express, the first European spacecraft to head for Mars. But the work reported in this issue also reflects the success of recent NASA missions such as Pathfinder, Mars Global Surveyor and Mars Odyssey, which have provided a wealth of high-quality data and a consequent renaissance in planetary science. The papers collected here do not say all there is to be said about research on Mars, but they show the scope and quality of current work. Much of the current interest in Mars stems from the possibility of finding traces of life there, either extant or in the past; it is almost as exciting to think that the planet might still be geologically active. When the current spacecraft arrive safely at Mars, we have every chance of finding out. Watch this space! Sue Bowler, Editor | |||||
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| Eta Carinae shows “model” behaviour Julian M Pittard reports on the ups and downs of a stellar survivor – which suggest that it is, in fact, two stars. Eta Carinae is a massive star that survived the greatest non-terminal stellar explosion known. But it has been suggested (see Pittard, A&G 2003 44 1.17–22) that the star is actually a member of a binary system. X-ray monitoring of Eta Carinae, led by Dr Michael Corcoran at NASA&Apos;s Goddard Space Flight Center, has recently confirmed the expected sudden sharp drop in flux in the 2–10 keV energy band. The timing of the decline agrees well with predictions based on a 5.52 yr orbital period. In this scenario, another massive star orbits Eta Carinae and their hypersonic stellar winds collide violently to produce plasma at more than 100 million K. This radiates mainly at X-ray energies, and the observed flux depends on the separation of the stars and their orientation. The X-ray lightcurve (lheawww.gsfc.nasa.gov/users/corcoran/eta_car/etacar_rxte_lightcurve/) is broadly consistent with the hypothesized, highly eccentric orbit, where the separation varies from about 30 AU to about 1.5–3 AU. It is around the time of closest approach that the X-ray flux drops precipitously. Detailed analysis of X-ray spectra should reveal whether the companion star causes Eta Carinae to eject extra mass at this time. Julian M Pittard | |||
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RAS thesis prizewinners The RAS is happy to announce the winners of the 2002 RAS Michael Penston and Blackwell Prizes and to present the winners with their prizes at the RAS meeting in May this year. Ms Sue Corbett, journals director of Blackwell Publishing, presented Dr Emma Bunce with the 2002 RAS Blackwell Prize. Prof. Ian Halliday, Director of PPARC, presented Dr Mark Wright with the 2002 RAS Michael Penston Astronomy Prize. The picture shows, from left to right, Ian Halliday, Mark Wright, Emma Bunce and Sue Corbett. The RAS Michael Penston and Blackwell Prizes are awarded for the best PhD thesis in astronomy and astrophysics, and geophysics and planetary science, respectively. Supervisors (who are Fellows of the RAS) are responsible for entering theses in the competition; details can be found at www.ras.org.uk/html/ras_medals.html. | |||
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