Adam appealed to my vanity and asked the following:

"...Huygens survival chances? Have they done another Beagle II? Did they get the code right?"

There's no comparison between Beagle-2 and Huygen. Beagle-2 was the work of amateurs while Huygen was designed and built by some of Europe's finest engineers and technicians. The Europeans have successfully flown solo Earth landers, e.g. ARD (Atmospheric Reentry Demonstrator). Also the Europeans have heaps of experience with military RVs (the British were pioneers in hypersonic aerodynamics). Unfortunately Huygen is Western Europe's first "solo" interplanetary atmospheric probe. Also, Titan is not exactly the best world in the Solar System to learn about designing interplanetary landers. Mistakes were made. Luckily, American engineers were looking over the European's shoulders through most of the design process. Some significant errors were caught early while late mistakes were caught before they became lethal, e.g. the Doppler shift error. People are currenly fussing over the CN (cyanide) emission problem. Titan has a nitrogen / methane atmosphere. In Huygen's shock layer, molecular nitrogen decomposes in atomic nitrogen while the methane decomposes into gaseous carbon and hydrogen. The caron and nitrogen then recombine into CN which is a very efficient radiator in red and ultraviolet. Most of Huygen's heating will be due to the CN radiation. There are concerns about whether Huygen's heat shield can handle the radiation.

Gary