At 03:22 PM 2/2/2003 -0800, Randall Clague wrote:
On Sun, 02 Feb 2003 13:59:11 -0800, Pierce Nichols <[EMAIL PROTECTED]> wrote:>However, getting it >spread evenly and reliably over the surface of the TPS during re-entry seem >to me to be a tricky problem. It's a really sweet operational model, but >the complexity and failure modes are daunting. Gary Hudson looked at this for Roton, and concluded that it isn't nearly as bad as the learned literature suggests. You don't need millions of 100 micron holes 15 mm apart all over the hull - which would be completely unmanageable and would clog anyway - if you're willing to carry some extra water to fill in the gaps. He was talking more like 1 or 2 mm holes, inches apart. Quite manageable if you treat the aeroshell as a jacket. Bottom line: "We've been moving water around for 6000 years. I'm confident that we know how to move water around."
Hrm... I'm inclined to take Gary's ideas with a grain of salt, but it passes the smell test. The question in my mind is how much more water, of course. I don't think you need (or would want) a grid of tiny, precise holes, but instead a material of a define porosity. It seems to me that you could source a metal foam to fit the bill.
-p
Mars or Bust!
www.marssociety.com
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