JimO,

I found your article under the URL:

http://msnbc.msn.com/id/6301146/

Thank you for pointing it out to me.

I have worked with many of the people who designed the heatshield for the Galileo Probe. The research and development effort that went into tha Galileo Probe heatshield was heroic. At the end of the process, people still did not have confidence in the design so huge safety margins were added. I know that many of the engineers involved were pleasantly surprised the heat shield actually worked. There was significant mass loss of the heat shield due to ablation. Special sensors (called ARAD gauges) were embedded in the carbon-phenolic of the heatshield to measure surface recession. The ARAD gauges were essential for backing out the descent trajectory to determine the Jovian atmospheric model (the scientists would never have allowed us the telemetry bandwidth if it was only for engineering data). Some of the ARAD gauges indicated the aft part of the heatshield's frustum had almost burned through (this near failure was with the huge safety factor). Something totally unexpected happened during the probe's entry and is still a very controversial topic amongst heat shield engineers. Unfortunately there is no research money to study the problem so all we can do is argue about it and feel frustration. I find it very ironic that given the heroic effort involved in designing the heat shield, the Galileo Probe almost failed due to a simple wiring error.

Gary