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This illustration shows how the fast flight of the Pathfinder came to an end. After entering the atmosphere of Mars at the speed of 17.000 miles an hour it was slowed down by parachutes and rockets.
The airbags opened and the vehicle hit the ground of Mars at a speed of 60 mph. Due to that speed the probe bounced back, as high as a four-storey building. Finally it ended up lying on the dusty surface of Mars.
Once the Mars Pathfinder lander has settled on the surface, pyrotechnic devices in the lander petal latches are blown to allow the petals to be opened. The latches locking the sturdy side petals in place are necessary because of the pulling forces exerted on the lander petals by the deployed airbag system.
In parallel with the petal latch release, a retraction system will begin slowly dragging the airbags toward the lander, breaching vent ports on the side of each bag, in the process deflating the bags through a cloth filter.The airbags are drawn toward the petals by internal lines extending between attachments within the airbags and small winches on each of the lander sides. It takes about 64 minutes to deflate and fully retract the bags.
There is one high-torque motor on each of the three petal hinges. If the lander comes to rest on its side, it will be righted up by opening a side petal with a motor drive to place the lander in an upright position. Once upright, the other two petals are opened.
About three hours is allotted to retract the airbags and deploy the lander petals. In the meantime, the lander's X-band radio transmitter will be turned off for the first time since before launch on December 4, 1996. This saves battery power and will allow the transmitter electronics to cool down from beeing warmed up during entry without the cooling system.It also allows time for the Earth to rise well above the local horizon and be in better position for communications with the lander's low gain antenna later in the morning. |
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