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Aviation History
2003
2003 - 0795.PDF
SPACEFLIGHT SHUTTLE DISASTER TIM FURNISS / LONDON & GRAHAM WARWICK / WASHINGTON DC Was access panel lost in orbit? Orbiter experiments recorder reveals anomalous sensor readings while Columbia was still off Californian coast Investigators are almost certain the Space Shuttle Columbia lost a wing access panel in orbit, but have not determined whether this is the source of the thermal breach that caused the orbiter to break up dur ing re-entry. Radar cross-section test ing has eliminated all but a carrier panel from consideration as the object observed separating from Columbia on its second day in orbit. Carrier panels seal the gap between the leading-edge reinforced carbon-carbon (RCC) panels and the underwing thermal-protection tiles. They carry smaller tiles through which pass bolts that allow the panels to be removed to provide access to the RCC attachments. Analysis of images from Columbia's launch indicate the piece of insulation foam that separated from the external-tank bipod area 82s after lift-off struck the underside of RCC panel 6 on the left wing New data shows warming trend began earlier leading-edge. The estimated impact footprint covers two carrier panels and the T-seals between neighbour ing RCC panels. Data on the orbiter experiments (OEX) recorder recovered from the Columbia debris points to a breach of the left wing leading-edge, with anomalous sensor readings earlier than first thought. The first to go off-nominal is a strain gauge behind the wing spar near RCC panel 9, outboard of 6. The reading started to rise 270s after re-entry began, 206s before the earliest anomalous event - and increase in yaw - detected in telemetry. The first tempera- < ture anomaly, recorded from a sensor in front of the spar on an out board attachment point for RCC panel 9, was 290s after entry inter face. Another sensor, behind the same spar, went off-nominal 135s later, while Columbia was still off the coast of California, peaking at 218°C (450°F) before going off-line when the wire burned through. This is at least 63s before the first temperature rise detected in telemetry from the left wheel well. Columbia accident investigation board member Roger Tetrault says the OEX recorded data from 670 sensors, including 15 in the left wing that all went "off-scale low" while Columbia was still off California. Seventeen sensors in the left wing show "a warming trend compared to previous flights" just 80s after entry interface, he adds. Impact testing has been delayed after analysis of the launch images showed the foam shed by the exter nal tank was larger than previously thought. Trajectory analysis suggests the piece weighed 0.9kg (21b) and hit at 195m/s (640ft/s), says Tertault. Another possibility is potential weakening of the RCC panels by pinholes caused by contamination by zinc oxide primer, exposed by deterioration of the paint, falling from the launch pad structure. JAPAN SPYSATS Japan launched optical and radar reconnaissance satellites by H2A booster from Tanegashima on 28 March, pri marily to monitor North Korean missile activities. The 850kg (1,8701b) optical satellite, thought to have 1 m (3.3ft) reso lution, and a 1,200kg radar satellite were built by Mitsubishi Electric. The $2.05 billion pro gramme includes two satellites for possible launch next year and four more up to 2009. BOEING JOINS Boeing will join the Lockheed Martin-General Dynamics team competing for the US Navy's Mobile User Objective System (MUOS), a multi-satellite con stellation to replace the Boeing-built UHF Follow-On mili tary communications fleet. The MUOS contract will be awarded in 2004, leading to initial opera tional capability in 2008 and full capability in 2013. SATELLITE SYSTEM German-Italian agreement clears the way for Galileo development Germany and Italy have settled their dispute over the division of responsibility for Europe's Galileo navigation satellite system, allow ing the €3.2 billion ($3.4 billion) programme to proceed into devel opment. The dispute had threat ened plans for the 30-satellite con stellation to enter commercial operation in 2008. Galileo Industries, the consor tium responsible for developing the system, will have headquarters in Germany. EADS Astrium will appoint the chief executive, while Italy's Alenia Spazio will have a deputy chief executive and control of the four main contracts. Germany will be responsible for the space segment, while Italy will focus on system engineering. The agreement still needs to be approved by the other participat ing countries, after which contracts will be shared out. The European Space Agency is now expected to release €550 mil lion for the development and vali dation phase. The European Union has started releasing its €550 mil lion contribution to keep the pro gramme on track. Development will culminate with the launch of two prototype satellites in 2005 for in-orbit validation of the system. Full deployment of the constella tion in 2006-7 will be carried out, and largely funded, by a concession holder. A call for expressions of interest was issued in late February, with the Galileo concession to be awarded in 2004. The estimated €220 million annual operation cost is to be recovered through user fees and receiver royalties. Galileo will provide four core position, velocity and time services. Open service, equivalent to civil GPS, is aimed at mass-market users, while paid-for commercial service is intended for professional users. Aviation will use the high-integrity, dual-frequency "safety-of-life" ser vice. Public regulated service is equivalent to military GPS. The European Commission intends to select a commercial operator to take over EGNOS, Europe's space-based augmentation system for GPS, when it becomes fully operational in June next year. The EC has proposed integrating the two programmes in a bid to help Galileo penetrate a worldwide satellite navigation market expected to total 1.8 billion users by 2010 and 3.6 billion by 2020. • Russia is to launch three Glonass/ Uragan navigation satellites in June, one an uprated Glonass B/Uragan M spacecraft. Three more Uragans will be launched later this year, and Russia hopes to have 24 Glonass satellites in orbit by 2004, including the first uprated Uragan Ks. 28 8-14 APRIL 2003 FLIGHT INTERNATIONAL www.flightinternational.com
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