Satellite falling to Earth

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  • Member since
    November, 2009
Satellite falling to Earth
Posted by Poppa Chris on Thursday, November 07, 2013 3:19 PM

http://www.cnn.com/2013/11/07/world/satellite-falling/index.html?hpt=hp_t2

 Not a "Chicken Little" event.  Interesting nonetheless.

---Poppa Chris---

Denham Springs, Louisiana USA

"Second star to the right - Then straight on until morning!" - Peter Pan

Celestron CPC1100GPS (XLT) - 279mm aperature, 2800mm Focal length. (f10) Celestron Ultima LX (70deg AFOV) Eyepieces 32mm thru 5mm, Canon EOS Rebel T2i DSLR, Backyard EOS imaging software, Orion Star Shoot Planetary Imager IV, Celestron Skymaster 15x70 binoculars

 

  • Member since
    July, 2008
Posted by Iggle on Thursday, November 07, 2013 6:35 PM

Am I crazy to think that stellites should only go up if they have a plan for controlled re-entry (assuming NEO)?  It seems crazy to me that we are still sending them up there and have no idea where/when they will come down.

  • Member since
    October, 2007
Posted by Aratus on Saturday, November 09, 2013 4:20 PM

GOCE was an unusual satellite intended to fly in the very edges of the atmosphere.   The chances of it hurting anyone is very, very small.   There are plenty of other human activites that that are millions of times more likely to hurt people.   We seem to tolerate those.

Aratus

Location:  North West Devon, UK

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  • Member since
    July, 2008
Posted by Iggle on Sunday, November 10, 2013 9:56 AM

Aratus, no doubt the risks are very small.  But why not use the last few, what? - atoms, ounces (not sure what unit of measurment would be used for ion propulsion) - of fuel to make a controlled reentry?   I am reminded of a story:

In his book Against the Gods:  The Remarkable Story of Risk, Peter Bernstein tells the story of a famous Soviet professor of statistics who refused to go down to the bomb shelters during German air raids over Moscow in World War II.  The professor’s reasoning:  “There are seven million people in Moscow.  Why should I expect them to hit me?”  Based on his study of statistics, he knew the chances of being killed on a given night were small.

When the professor suddenly showed up at the shelter one night, his friends asked him what changed his mind.  He replied, “Look, there are seven million people in Moscow and one elephant.  Last night they got the elephant.”

  • Member since
    August, 2007
Posted by Primordial on Sunday, November 10, 2013 3:42 PM

Iggle : That's good, I guess zoos are a good thing to have around.

  • Member since
    October, 2007
Posted by Aratus on Monday, November 11, 2013 4:52 AM

Iggle

Aratus, no doubt the risks are very small.  But why not use the last few, what? - atoms, ounces (not sure what unit of measurment would be used for ion propulsion) - of fuel to make a controlled reentry?

I don't think an ion drive would be much use in controlling a descent.  A retro-rocket means 'weight' and that is still an issue with spacecraft.   I imagine that if GOCE landed on a city and killed people, then a retro-rocket would be made mandatory.   As it is GOCE landed in the South Atlantic.   There is a road near to us without a pavement/sidewalk.  Anyone walking along it, especially in the dark, is in increased danger of being hit by a car.   Simply put, no one has been killed along that road in living memory, and no one is going to spend the extra money on a pavement until someone is killed.    Bolting the stable door after the horse has bolted is human nature.Confused

Aratus

Location:  North West Devon, UK

-------------------------------------------------

Celestron Nexstar8i (8" SCT).

Celestron Skymaster binoculars 15x70

Other:0.63 & 0.33 correctors. X2 & X4 barlow.

Imagers: Meade DSI & Celestron NexImage.  Canon EOS 550D

 

 

  • Member since
    November, 2009
Posted by Poppa Chris on Monday, November 11, 2013 8:44 AM

Ion drives are very low impulse thrusters.  They don't have the brute force needed over a short time frame to de-orbit a satellite.  Their forte' is low force, long duration sustained acceleration for interplanetary and hopefully interstellar voyages.  

---Poppa Chris---

Denham Springs, Louisiana USA

"Second star to the right - Then straight on until morning!" - Peter Pan

Celestron CPC1100GPS (XLT) - 279mm aperature, 2800mm Focal length. (f10) Celestron Ultima LX (70deg AFOV) Eyepieces 32mm thru 5mm, Canon EOS Rebel T2i DSLR, Backyard EOS imaging software, Orion Star Shoot Planetary Imager IV, Celestron Skymaster 15x70 binoculars

 

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