RE: To Jupiter!!
May 19, 2012 at 7:54 pm
(This post was last modified: May 19, 2012 at 8:39 pm by Anomalocaris.)
Easily. Take for example the radio thermal battery used on the voyager probe. Each is good for about 1KW of power output On average over, say 15 years. This means the probe can melt about 5 pounds of ice per second for 15 years, or 1.1 million tons of ice in 15 years. This means it can melt a hole 1 meter by 1 meter in size and 600 miles in depth in 15 years.
In real life it can't melt quite that much because the ice would have started way below freezing temperature, so the battery would need to warm up the ice to the melting point before supplying the heat of fusion. Also ice is not a perfect insulator so some of the heat will be lost warming ice not meant to be melted. But the battery only needs to achieve 3% of the theoretical efficiency I calculated to go through 20 miles of ice.
[correction, I made a mistake in calculating water's heat of fusion.
It should be about 350 Kj / kg, not 350 J / kg, which invalidates the above calulation. But it is still possible to melt through 20 miles of ice because newer thermal batteries like the ones on cassini can much better than 1 KW for 15 years, in fact the can do 4 kw for 15 years. So the Cassini batteries can melt 1 meter by 1 meter hole through about 30 miles of ice in 15 years, and the probe could be made smaller in section than 1meter by 1 meter, and rtg can be specially made to generate lots of heat]
In real life it can't melt quite that much because the ice would have started way below freezing temperature, so the battery would need to warm up the ice to the melting point before supplying the heat of fusion. Also ice is not a perfect insulator so some of the heat will be lost warming ice not meant to be melted. But the battery only needs to achieve 3% of the theoretical efficiency I calculated to go through 20 miles of ice.
[correction, I made a mistake in calculating water's heat of fusion.
It should be about 350 Kj / kg, not 350 J / kg, which invalidates the above calulation. But it is still possible to melt through 20 miles of ice because newer thermal batteries like the ones on cassini can much better than 1 KW for 15 years, in fact the can do 4 kw for 15 years. So the Cassini batteries can melt 1 meter by 1 meter hole through about 30 miles of ice in 15 years, and the probe could be made smaller in section than 1meter by 1 meter, and rtg can be specially made to generate lots of heat]
