View Full Version : Discussion: Rosetta Can "Smell" a Comet

2004-Aug-22, 04:10 PM
SUMMARY: One experiment on board the European Space Agency's Rosetta spacecraft will let it cook particles from a comet in a miniature oven, and then "smell" the results. When Rosetta arrives at Comet 67P/Churyumov-Gerasimenko, it will send down a small spacecraft to actually land on its surface. This lander will be able to scoop up and drill samples from the comet's surface and then place them in an Evolved Gas Analyser. This tiny oven can heat the particles to 800 degrees Celsius which converts them into gas which can then be analyzed to understand what chemicals are present.

What do you think about this story? Post your comments below.

2004-Aug-22, 05:50 PM
That's great news.

Most of the sample should volatilize long before reaching 800 degrees Celsius, if the comet is mostly made of volatile compounds made from light elements, like H, C, N and O.

Such compounds - - - like water, ammonia, carbon dioxide, and hydrocarbon compounds of H and C, like methane, ethane, propane, etc., - - - volatilize at low temperatures. Notable exceptions are solids made solely of Carbon - - - diamonds and graphite.

"Strange" isotope ratios in heavy elements (Te, Xe, Ba, Nd, Sm) are seen in meteorite inclusions made of these light elements. The Galileo mission also found evidence of "strange" Xe in Jupiter's atmosphere.

I am encouraged that the last sentence of the full story says:

"This device will find out what gases are present in any particular sample and measure stable isotope ratios."

The results may show whether "strange" isotope ratios are commonplace in the solar system or exist only in refractory "interstellar" grains from beyond the solar system.

Hopefully they will have a way to measure the amount of more refractory, non-volatile material that remains after heating to 800 degrees Celsius.

In analyzing meteorites, we routinely heated to 1600 degrees or higher to melt the samples completely. As I recall Iron Sulfide (FeS) melts at about 950 degrees Celsius under vacuum. Iron (Fe) and many silicate minerals melt at even higher temperatures.

With kind regards,