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To: NordP
> Not by “soft” landing. The last was with NASA’s version of bubble wrap. This one was by parachute and thrusters. Absolutely amazing!!!!

I think you're thinking of the Mars rovers of the last decade. As far as I know, the Viking lander was a soft landing (this is from the Wikipedia page):

Propulsion was provided for deorbit by a monopropellant hydrazine (N2H4) rocket with 12 nozzles arranged in four clusters of three that provided 32 N thrust, giving a delta-V of 180 m/s. These nozzles also acted as the control thrusters for translation and rotation of the lander. Terminal descent and landing was achieved by three (one affixed on each long side of the base, separated by 120 degrees) monopropellant hydrazine engines. The engines had 18 nozzles to disperse the exhaust and minimize effects on the ground and were throttleable from 276 N to 2667 N. The hydrazine was purified to prevent contamination of the Martian surface. The lander carried 85 kg of propellant at launch, contained in two spherical titanium tanks mounted on opposite sides of the lander beneath the RTG windscreens, giving a total launch mass of 657 kg. Control was achieved through the use of an inertial reference unit, four gyros, an aerodecelerator, a radar altimeter, a terminal descent and landing radar, and the control thrusters.
You wouldn't need all that descent control gear if you planned to merely bounce. I'm still looking for a definitive reference on the NASA site. But my recollection from 1976 was that it was a controlled thruster landing.

I think it's funny as hell that nobody wants to remember that we're simply picking up a program we dropped and ignored for 30 years...

69 posted on 05/25/2008 9:18:27 PM PDT by dayglored (Listen, strange women lying in ponds distributing swords is no basis for a system of government!)
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To: dayglored; NordP
Okay, here it is from the NASA site (http://www.nasa.gov/mission_pages/viking/viking30_fs.html):
About 2 a.m. July 20, 1976, the Viking 1 lander separated from the orbiter and began its hazardous descent to the surface. Plunging through the thin Martian atmosphere at nearly 10,000 miles per hour, the lander was protected by a heat-shielding aeroshell.

At about 19,000 feet, a large parachute was deployed, slowing the hurtling spacecraft. At 4,000 feet, the parachute and aeroshell were released and rockets fired, further slowing the lander's descent to just six miles per hour.

For 19 agonizing minutes -- the time it takes a radio signal to travel to Earth from Mars -- the Viking team held their collective breath and waited for confirmation that the lander was down safely and was functioning.

"We got telemetry from the lander all the way down close to the surface, so we knew that the parachute had worked," said Martin. "We knew the thrusters had worked. We knew the guidance system was working and that the radar was working. But there was a period of those 19 minutes when we didn't know whether the lander landed successfully. That was nail-biting."

It was finally confirmed -- the Viking 1 lander had made it! "The excitement was overwhelming!" said Young. "People were hugging each other, jumping up and down -- doing all those things you do when an extraordinary event has taken place."

Viking 1 lander first image from Mars surfaceImage Right: This image, taken by the Viking 1 lander shortly after it touched down on Mars July 20, 1976, is the first photograph ever taken from the surface of Mars. Part of footpad #2 can be seen in the lower right corner, with sand and dust in the center of it, probably deposited during landing. Credit: NASA

Immediately after touchdown, the lander's camera took its first picture and relayed the historic image back to Earth. That first picture was of the lander's foot -- to see how far it had sunk into the Martian surface. "And we couldn't have asked for anything better," said Martin. "That picture was really worth a thousand words."

The Viking team repeated this gut-wrenching process with Viking 2, which settled solidly on Martian soil Sept. 3, 1976.

I think it's a riot that the described the same "19 minutes of agony" as the lander descended to the surface. The more things change...
71 posted on 05/25/2008 9:22:33 PM PDT by dayglored (Listen, strange women lying in ponds distributing swords is no basis for a system of government!)
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