One university at this year's Utah Cubesat Workshop, is designing a re-entry cubesat.
Talk about the ultimate ham radio fox hunt! Find this pebble somewhere over a few million square miles...
The problem is having a transmitter to survive the re-entry... One figure is that about 300 Killowatt Hours of energy has to be disipated in a few minutes.
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?
With the cheap $8k launches and only 3 month mission life, this idea of concentrating on making an interesting mission at the re-entry phase is a new opportunity..
The ultimate fox hunt?
Bob, WB4APR
Ok, Say can anyone find me this info?
The shuttle average orbital speed is 17580 MPh.
So launch starts at zero, and ends up at 17580
then coming back down goes from 17580 to zero.
Ok, Now what I want is,,
At Time = zero it's zero MPH, at t+1 min it's now at what altitude, and what speed? at T+2 min alt and speed?
at T+3 in alt and speed
continue all the way to orbit.
Now do it the other way, at time od de orbit burn it's at what altitude and 17580 MPh, at t+ 1 min after burn it;'s at alt and speed,
etc, all the way til it has landed,
does anyone have this information?
Joe
Bob Bruninga wrote:
One university at this year's Utah Cubesat Workshop, is designing a re-entry cubesat.
Talk about the ultimate ham radio fox hunt! Find this pebble somewhere over a few million square miles...
The problem is having a transmitter to survive the re-entry... One figure is that about 300 Killowatt Hours of energy has to be disipated in a few minutes.
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?
With the cheap $8k launches and only 3 month mission life, this idea of concentrating on making an interesting mission at the re-entry phase is a new opportunity..
The ultimate fox hunt?
Bob, WB4APR _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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In the case of Delta II second stage tanks some analysis concluded that what allows them to survive reenty is that a hole initially burns in one end which results in a shape that creates a shockwave. The shockwave then deflects most of the heat around the tank.
Some pictures if you're curious. http://orbitaldebris.jsc.nasa.gov/reentry/recovered.html
Probably hard to implement on a sub-nanosat scale but suggests another approach.
Lee
On Sunday 09 August 2009 15:16:04 Bob Bruninga wrote:
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?
With the cheap $8k launches and only 3 month mission life, this idea of concentrating on making an interesting mission at the re-entry phase is a new opportunity..
The ultimate fox hunt?
Bob, WB4APR _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (3)
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Bob Bruninga -
Joe -
Lee McLamb