Jun 4 1996
From The Space Library
NASA and the Italian Space Agency released the investigative report on the failed tethered satellite system (TSS) experiment conducted during Shuttle Columbia's Mission STS-75 in February 1996. The 358-page report, produced by a board established to investigate the incident, concluded that a breach in the layer of insulation surrounding the tether conductor, possibly the result of contact with debris, led to the failure. According to the report, the breach in insulation allowed an electrical current to jump from a copper wire in the tether to an electrical ground, causing the breakage: "the tether failed as a result of arcing and burning of the tether, leading to a tensile failure after a significant portion of the tether had burned away." The board noted that NASA scientists had already announced findings regarding tether current and voltage measurements, concluding that the unexpected breakage of Columbia's tethered satellite did not indicate any fundamental problem with the concept of the TSS. Furthermore, the board recommended that during future experiments, scientists should take greater precautions to ensure that neither debris nor high-voltage arcing compromised the tether's strength.
Arianespace, the commercial arm of the European Space Agency, suffered a major setback in its bid to maintain control of the satellite-launching market in the face of competition from U.S. companies. Only seconds after the launch of Ariane 5, a huge rocket intended to launch satellites, Arianespace had to blow up the rocket when it veered severely off course. Arianespace had spent 10 years and more than US$7 billion to develop the 674-foot (205-meter), 821-ton (750,000-kilogram or 750-tonne) vehicle. Also lost in the explosion were satellites valued at more than US$500 million. Arianespace had projected a launch reliability of 98.5 percent for the rocket, considering failure so unlikely that the company had guaranteed a free launch to customers if the launch failed. A spokesperson for Arianespace acknowledged the disappointment of the failed test, but promised that the company would continue as the world's leader in launching satellites. Aerospace industry analysts predicted that U.S. companies such as Lockheed Martin would likely gain an increased foothold in the market because of the European company's misfortune.
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