Mir To Crash Into Pacific

b0z writes "According to an article on Yahoo! the Russians are planning to dump Mir into the ocean in February. According to the article, the $40 million that MirCorp has raised is not enough to save Mir. Also, it is noted that Mir has been in use much longer than the engineers that made it intended." Of course, I'll believe this when I "see" it - the saga of Mir continues.

Comments

Re:There goes another bit of the ecosystem...

[mmontour]

Now, imagine a space station crashing through the atmosphere, heating up to insane temperatures, and falling into the middle of the ocean, where the water temperature stays mostly constant. If you don't think that is going to have a measurable effect on a large chunk of water, you haven't taken any thermo or bio classes...

Oh, please! Let's imagine that when Mir hits, it is at the same temperature as the surface of the sun (5700 K), while the ocean where it lands has a temperature of 280K. Let's say that Mir is made of steel with a total mass of 100,000 kg.

Heat capacity of steel = 447 J/(kg*K) , heat capacity of water = 4169 J/(kg*K).

So the heat energy supplied by the station is (447)*(100000)*(5700 - 280) = 2.42*10^11 J. Dividing by the heat capacity of water, we get a result of 5.8*10^7 kg*K.

In order to calculate a temperature rise, we need to decide how much of the ocean's volume to consider. For the first calculation, consider a cube of water 100m on each side. I hope you will all agree that this is an absolutely tiny fraction of the entire Pacific ocean.

The volume of water in this 100m cube is (100^3) =10^6 m^3, and the density of water is 1000 kg/m^3. Therefore, the mass of water in this cube is 10^9 kg.

So, (deltaT)*(10^9 kg) = 5.8*10^7 kg*K

deltaT = 0.058 K (or 0.10 degF for Americans).

Now take a look at http://www.icess.ucsb.edu/geos/1112.html , a page studying the El Nino phenomenon. Look at the satellite photos on that page, and figure out for yourself how much impact a 0.058 degree temperature rise in a 100m section of the Pacific ocean is going to have. Also note the section in the text which says "On warm sunny days, the surface waters can heat up by as much as 1-2 degrees C during the daytime hours".

Granted, any fish which happens to be at "ground zero" is going to get cooked, but the ecosystem is going to be completely indifferent to the event (at least from a thermodynamic perspective).

p.s. The environmental damage caused by industrial cooling-water is real. However, there you have a continuous source of heat energy rather than a one-time addition of a heated space station.

Re:Plea...

[wesmills]

One Microsoft Way - Redmond VA

I pity whoever in Virginia has this address ... Washington might be a better state to ditch it in, anyway. :)

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Re:What about the radiation?

[dnnrly]

Um? Where did you get the idea that Mir was radioactive? To start with, there is no nuclear pile aboard. a) it's too heavy and inconvenient to put up their (not only the pile but all that shielding as well) and b) it wasn't strictly necessary since it's easier to work things so that they draw less power and stick a couple of photoelectric cells (albeit big ones) to side of the station!

Before you go on about it being irradiated in outer space, I'd just like to point out that cosmic radiation just isn't strong enough there and any solar winds are mostly deflected by the earths magnetosphere. Anyway, even if Mir gets a good dose of beta radiation (free electrons for the uninitiated), any charge that builds up will just be 'absorbed' by the atmosphere. You probably get more extra electrons form solar wind in a second than you would form Mir no matter how long it had stayed up! As for alpha particles I think their only dangerous if their fast moving.

Not as if any less radiation is put into the sea by you average Nuclear power station or sunken nuclear submarine in the baltic sea.

dnnrly