Difference between revisions of "Talk:Propellants"
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2)The other thing regards unmanned cargo landers: Anyone looking into solid propellants for landing? Perhaps a 'rough-rider' system that came down like a semi-controlled bomb and used solids to brake velocity even with high acceleration loads. . . ? | 2)The other thing regards unmanned cargo landers: Anyone looking into solid propellants for landing? Perhaps a 'rough-rider' system that came down like a semi-controlled bomb and used solids to brake velocity even with high acceleration loads. . . ? | ||
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+ | -------------- | ||
+ | Yes and Yes, | ||
+ | 90% peroxide (90 parts H2O2 10 parts H2O) burned with 21 parts C2H5Oh or CH3OH (Ethanol or Methanol) | ||
+ | at 300 psi, with a 40:1 expansion ration has a vacuum ISP of about 300. :) | ||
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+ | Well surveyor was a solid lander- mostly. It is nearly impossible to do without a controllable/throttlible descent engine (I've tried) | ||
+ | but Surveyor dumped most of it's orbital velocity with a solid that it ejected before landing. (3 vernier N2O4/N2H4 and 6 cold gas jets) | ||
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+ | -Gary | ||
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+ | For calculating Isp, download the AFAL tool from http://www.dunnspace.com/isp2001.zip |
Latest revision as of 19:15, 24 October 2008
Just two questions here: 1)Does anyone happen to know how to calculate the specific impulse of a given propellant combination? I'm thinking Propellant-grade hydrogen peroxide and alcohol for a lunar lander, but I'm not sure about calculating the Isp for that particular combination.
2)The other thing regards unmanned cargo landers: Anyone looking into solid propellants for landing? Perhaps a 'rough-rider' system that came down like a semi-controlled bomb and used solids to brake velocity even with high acceleration loads. . . ?
Yes and Yes,
90% peroxide (90 parts H2O2 10 parts H2O) burned with 21 parts C2H5Oh or CH3OH (Ethanol or Methanol) at 300 psi, with a 40:1 expansion ration has a vacuum ISP of about 300. :)
Well surveyor was a solid lander- mostly. It is nearly impossible to do without a controllable/throttlible descent engine (I've tried)
but Surveyor dumped most of it's orbital velocity with a solid that it ejected before landing. (3 vernier N2O4/N2H4 and 6 cold gas jets)
-Gary
For calculating Isp, download the AFAL tool from http://www.dunnspace.com/isp2001.zip