Yeah, it might wind up being a super-sonic "Lawn Dart"! Jim KQ6EA
--- On Sun, 8/9/09, G0MRF@aol.com G0MRF@aol.com wrote:
From: G0MRF@aol.com G0MRF@aol.com Subject: [amsat-bb] Re: New Cubesat - the Ultimate Fox Hunt To: bruninga@usna.edu Cc: amsat-bb@amsat.org Date: Sunday, August 9, 2009, 4:31 PM
In a message dated 09/08/2009 19:42:06 GMT Standard Time, nss@mwt.net writes:
Why is it that all re-entries always end in the ball of fire over just a few minutes. Why cannot the re-enetry energy be disipated over a longer period to make it more survivable. Of course, if they could, they would. It appears to be the nature of the beast. You are entering an ever denser medium, so the drag has to escallate and you end up with the 6/7 minute burn.
What if the surface of the re-entry vehicle radically changed during the
re-entry phase? As the density of the atomosphere increased, the surface area decreases. An ablative system that instead of burning off a thin skin of material as in most re-entry systems, you planned on burning off 95% of the original drag volume? What re-entry profile could be achieved Could we make a golfball core "pinger" that could survive?
Or, the not so 'cube'sat structure is an aerodynamic shape made from a cast ceramic material which glides in at a shallow angle allowing the energy to be dissipated over a much longer period of time. OK the solar cells burn off but an internal antenna would be OK as ceramics are fairly transparent to RF and a battery would provide the final hour or so of tlm. Would love to see the temp readings as it comes down. Would not love to be on the final end of the trajectory when it arrives.
David G0MRF
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