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Color Panorama: Sol 1
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Pathfinder enters the upper atmosphere of Mars at 10:02 PDT and at a velocity of approx. 26.500 Km/hour and begins the sequence of events that will land the Spacecraft on the surface. From this point on, the only likely signal from the Spacecraft will be the carrier wave, a single frequency radio wave. The shifting frequency of the carrier, know as the "Doppler shift", will provide an indication of the decelerations occurring during entry and parachute deployment. The Spacecraft is also designed to send back a frequency-keyed signal following certain key events (this signal is called a "semaphore"). The semaphore is very weak and is not expected to be received in real time. However, careful analysis after-the-fact of the broad frequency spectrum recording of the radio signal will give the Operations Team considerable information on how events unfolded during the rapid descent to the surface.
Entry, descent and landing (EDL) takes approximately 4,5' and follows the sequence below:
Spacecraft rapidly decelerates in the atmosphere using the heatshield
Parachute deploys
Heat shield separates
Lander releases from backshell, descends on bridle
Radar altimeter returns information on altitude
Airbags inflate
Rocket-assisted deceleration (RAD) engines fire
Bridle cable is cut
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(Dettagli)
