24th February 2014 Sol 552

We have succesfully passed through Dingo Gap, and this NavCam image shows the rearward view, where we have driven over the dune.

Its is also a great view of the the Multi Mission Radio Isotope Thermal Generator (RTG) with its cooling fins on Curiosity.  When designing Curiosity, the Engineers decided that an RTG would provide more consistent power than solar panels and would therefore allow the rover to drive faster, further and do more scientific measurements.  Our RTG is powered by the decay of Plutonium-238. 

Since about the 1960s, energy from nuclear decay has been used to power spacecraft. RTGs use the thermal energy generated from alpha decay to generate a temperature difference across hundreds of thermocouples.  As most of the power is dissipated as heat it allows us to maintain Curiosity at a working temperature, in addition to providing about 100 W electrical power.

Thermoelectric conversion has a relatively low efficiency, but requires no moving parts, which is a major advantage for Curiosity because we have to operate for many years without maintenance. Most of the NASA RTGs that have been flown on missions have hugely exceeded their original design life.  Probably the most impressive examples are the Voyager probes, whose RTGs are still producing enough power (at the time of writing) for them to return valuable scientific data over 35 years after they were launched!  They are the most distant man-made vehicles.

One of the other things you can see on this image is the ‘billy can’ in the top left, that covers the UHF transmiter.  One of the few signs of damage on landing was the slight dent on this outer casing.