Fuel cells

Fuel cells can be considered a subset of primary batteries. The distinction is that the electrolytes or reactants are stored separately: for large energy requirements the packaging of reactants separately from the reaction vessel is more efficient and therefore results in higher energy densities. The most usual types use hydrogen and oxygen, although methanol/air technologies are under development for terrestrial applications such as mobile communications. The fuel cells used on the Space Shuttle generate 12 kW with a very respectable specific power of 275 Wkg~1.

The modest power requirements of planetary probes, coupled with the relatively high cost and complexity (particularly with regard to hydrogen storage) means they are rarely used on planetary probes - the only relevant case being the Apollo lander.

As an aside, the electrochemical conversion technology of fuel cells can be applied differently, using electricity (from solar panels for example) to convert CO2 into oxygen. Similarly, a zirconia cell, like that used in fuel cells, was used on the MPL TEGA instrument to sense the presence of oxygen in gases evolved from a soil sample.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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