Posted by at 16:49  2 Responses »
Sep 242009

I’ve often wondered why re-entry heat shields on spacecraft were such a big deal. The massive fireball that results from re-entry is due to the tremendous speed with which the spacecraft re-enters the atmosphere, resulting in aerodynamic heating (and not, as Mr. Stokes points out in the comments, due to atmospheric friction as I had originally written). Slow down, and you don’t have that problem.

After some digging, the answer was obvious. You need fuel to slow down. Where’s that fuel come from? That’s right: Earth. In other words, you’d have to take it with you to begin with, making your launch vehicle that much heavier. It’s more efficient to use the atmosphere itself as a giant brake, thereby necessitating heat shields.

Another mystery solved. You’d think I would’ve been able to figure this out, but it’s plagued me for years.  Part of the problem, no doubt, is the contamination of various pop sci-fi properties that conveniently ignore the problem of fuel (I’m looking at you, Star Trek).

Aug 172009

So, after using Chrome for several months, I’ve decided to go back to Firefox.

Firefox has excellent extension support, but more important is that it has extensions for ad blocking/filtering.  Chrome doesn’t.  There are ways around this and the one I was using is a little app called Privoxy, which runs a proxy on your local machine that filters out potentially undesirable stuff.  However, it’s clunky and over-aggressive, often preventing me from accessing webpages altogether.  This is not cool.

With the recent speed improvements in Firefox (speed being the reason I switched to Chrome in the first place), as well as even more improvements coming in upcoming versions, I’ve decided to switch back.