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Aviation History
1998
1998 - 1057.PDF
SPACEFLIGHT ESA identifies cause of Ariane 5 roll as new launches approach TIM FURNISS/LONDON THE EUROPEAN Space Agency (ESA) has confirmed that roughness inside the first stage engine nozzle was to blame for the roll that endangered the success of the second Ariane 5 launch in October 1997. A solu tion is in prospect as Arianespace prepares the launcher for fully commercial flights. ESA looked at two potential caus es for die 900Nm (Newton metre) torque roll experienced with the firing of die Ariane 502's Vulcain first stage (Flight International, 25 February-3 March). One possibility focused on a mechanical breakage, but ESA now believes mat die prob lem lay with "roughness" of the internal surface of the Vulcain noz zle, causing the boundary layer of die main exhaust plume to spiral. Although ESA has not given full details, the "roughness" is thought to involve the surface configura tion of the coolant pipes that spiral around the interior of the nozzle, An additional attitude control unit is already planned for the Ariane 503 mission, the third and final ESA funded demonstration flight, to obtain inflight confirma tion of the roll problem. A solution is also proposed to counteract the roll by a slight repositioning of the two turbine exhaust ducts that run down either side of the nozzle. The Ariane 503, which will fly with the Aerospatiale-built Auto matic Re-entry Demonstrator cap sule, should be ready to launch by July. A commercial payload still needs to be found, which makes a September launch date more likely. European commercial launcher organisation Arianespace has ruled out flying without such a payload, and is still committed to the target of launching a fully commercial Ariane 504 flight by year-end. Talks are known to have taken place with Eutelsat, the European communications satellite organisa tion, on flying the Matra Marconi Space built Hot Bird 3, or an Aerospatiale Eutelsat W24on 503. Under an agreement widi ESA, in which one of the Ariane 5s ordered by Arianespace was transferred to the 503 mission, Arianespace will pay ESA about $35 million of the commercial launch fee. Only two of more than 40 craft on Arianespace's orderbook - the ESA Envisat and X Ray Multi Mirror telescope - arc too heavy to be carried on the Ariane 4. • First EOS launch suffers a six month setback THE LAUNCH of the first satellite in the Earth Ob serving System (EOS), the centre piece of NASAs Mission to Planet Earth programme, has been de layed by at leastsix months after the discovery of a series of ground con trol software faults. Faults in the EOS Data and Information System (EOSDIS) are now expected to delay the launch fromjune to "at least the end of the year", says NASA. Around another 10 EOS craft are to be launched in the controversial programme, which has suffered delays, budget cuts and specification changes. The first'5,185kg spacecraft, the EOS AM-1, was due to have been launched from Vandenberg AFB, California, aboard an ILS Inter national Launch Services Atlas 2AS, carrying 20 instruments to observe the Earth from polar orbit. "Significant performance prob lems" were found in the EOSDIS control centre flight operations segment (EOS) that supports the command and control, spacecraft instrument health and safety, the planning and scheduling of instru ment operations, and analysis of spacecraft trends and anomalies. The FOS was developed by Raytheon under contract to Lockheed Martin, the manufactur er of the EOS AM 1. Programme managers expect it to take "several weeks" to under stand clearly whether the best approach is to correct the software or to take other measures. • Microprobes team selected A NINE-STRONG SCIENCE TEAM has been selected by NASA to manage the Mars Microprabes, which will fly as piggyback pay- loads aboard the Mars '98 Polar Lander, pic tured at Lockheed Martin Astronautics in Denver, Colorado. The Microprobes, to be launched in January 1999, are flying as the Deep Space 2 mission in the New Millennium programme and will separate from the lander before it enters the atmosphere. Each Micro- probe will search for water ice in the soil using a small drill to bring a soil sample inside the probe, heat it and look for water vapour. NEWS IN BRIEF m ARTEMIS UNVEILED The European Space Agen cy's geostationary orbiting Artemis communications technology satellite has been unveiled at Alenia Aero- spazio in Rome amid fears that its scheduled launch on a Japanese H2 Alpha Plus in 1999 is likely to be delayed at least until February 2000 because of development prob lems with the new booster. • SUPERBIRD CONTRACT Hughes Space and Com munications has won its sixth satellite manufacturing order in a month, with a contract to build the Superbird 4 for Space Communications of Japan. The HS-601 High Power model will be launched in 2000 on an Ariane 4 booster. • SLOVAK MISSION Lt Col Michal Fulier and Maj Ivan Bella of the Slovak Air Force have started training at Russia's Star City near Mos cow for a proposed seven to 10 day mission on the Mir 1 space station in early 1999. • ASTRO MESH Astro Aerospace, a subsidiary of Canada's Spar Aerospace has won a C$30 million ($20 million) contract from Hughes Space and Communications to build two 12.25m diameter AstroMesh unfurlable anten nas for the Thuraya communi cations satellite system. They will provide mobile communi cations services to the develop ing regions within Asia, Africa and Europe in 2000. • NEW ATLAS ILS International Launch Services has unveiled an up graded version of its Atlas 2AR, now rebranded under the Atlas III name. The basic Atlas rriA uses a Russian RD- 180 for the first stage, plus a single RL-10A second stage, while the uprated version, dubbed the Atlas IIIB, will usetwoRL-lOAs. FLIGHT INTERNATIONAL 22 - 28 April 1998
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