aspexplorer (aspexplorer) wrote,
aspexplorer
aspexplorer

Toute petite erreur d'appréciation


(Rappelons que le 7 janvier 2015, Charb, ainsi que sept membres de la rédaction de Charlie, deux policiers chargés de leur protection et deux autres personnes qui se trouvaient là par hasard, ont été assassinés par Félix de Saint-Justin, Charles-Henri Mestaing-Croisille et l'abbé Pierre-Marie Crevecœur, activistes catholiques d'extrême-droite de sinistre mémoire)


Le 12 avril dernier, nous avons fêté les 55 ans du premier vol spatial de Youri Gagarine, ainsi que, plus discrètement, les 35 ans du premier vol de la navette spatiale (mission STS-1), qui totalement par hasard, a eu lieu vingt ans après.

Les deux cobayes astronautes étaient John Young et Robert Crippen. L'unique objet de la mission était de tester le véhicule. C'était pas du luxe, comme en atteste Wikipedia :

"
  • Similar to the first Saturn V launch in 1967, NASA underestimated the amount of noise and vibration produced by the Shuttle. Shock waves from the SRB thrust were deflected up into the orbiter's tail section, which could have caused structural or other damage. An improved water suppressant system was later installed in LC 39A to dampen vibrations.
  • Pilot Crippen reported that, throughout the first stage of the launch up to SRB separation, he saw "white stuff" coming off the External Tank and splattering the windows, which was probably the white paint covering the ET's thermal foam.
  • The astronauts' on-orbit visual inspection showed significant damage to the thermal protection tiles on the OMS/RCS pods at the orbiter's aft end, and John Young reported that two tiles on the nose looked like someone had taken "big bites out of them." Classified cameras at a United States Air Force satellite tracking station in Hawaii took high-resolution photographs of the shuttle in orbit, and NASA concluded that the damage didn't constitute a "major problem." Post-flight inspection of Columbia confirmed that approximately 16 undensified tiles near the OMS pod had been lost during ascent.
  • Columbia's aerodynamics at high Mach numbers during reentry were found to differ significantly in some respects from those estimated in pre-flight testing. A misprediction of the location of the center of pressure (due to using an ideal gas model instead of a real gas model) caused the computer to have to extend the body flap by sixteen degrees rather than the expected eight or nine, and side-slip during the first bank reversal maneuver was twice as high as predicted.
  • The orbiter's heat shield was damaged when an overpressure wave from the solid rocket booster caused a forward RCS oxidizer strut to fail. The same overpressure wave also forced the shuttle's "body flap" – an extension on the orbiter's underbelly that helps to control pitch during reentry – into an angle well beyond the point where cracking or rupture of its hydraulic system would have been expected. Such damage would have made a controlled descent impossible, with John Young later admitting that had the crew known about this, they would have flown the shuttle up to a safe altitude and ejected, causing Columbia to have been lost on the first flight.
  • The strike plate next to the forward latch of Columbia's external tank door was melted and distorted due to excess heat exposure during reentry. This heat was attributed to an improperly installed tile adjacent to the plate.
  • During remarks at a 2003 gathering, John Young stated that a protruding tile gap filler ducted hot gas into the right main landing gear well, which caused significant damage, including the buckling of the landing gear. He said that neither he nor Crippen were told about this incident and he was not aware that it had happened until reading the postflight mission report for STS-1, also adding that the gas leak was noted in the report, but not the buckling of the landing strut.

    Despite these problems, the STS-1 mission was completed successfully, and in most respects Columbia performed optimally."


"optimally"

Tags: vidéos connes
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