Axel
Drive Technician
- Joined
- Dec 31, 2008
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@Urwumpe
The Ammonia-Etylen mixture sounds very intresting, but it has to be proven.
Methane-LOX seems to be the easiest way. But a NTR has a nice lifetime cycle of 35 hours (!) at 2600K core temperature. This would enable many missions to various targets with same lander. Chemical engines have lifetime cycle under 1 hour, after 2-3 missions the lander's engine would need intensiv servicing, ofcourse thats cheaper at all than an expensive reactor, but if the mothership is very far and long away from home maybe a better point for the NTR. The reactor weight is lesser than the extra fuel for the pure ch4-lox chemical lander:
empty mass ch4-lox: 19mT
fuel mass: 75mT
total mass 94mT
CH4-NTR:
empty mass 25.5mT
fuel mass 37 mT
total mass 62.5 mT
We need 6,5mT mass for a NTR@250kN thrust, [email protected], 5.5t@182kN, 9t@350kN, 18.5t@1000kN.
So 31.5mT more for the chemical variant. But you are right, i dont' know about its possible to throttle down a NTR savely and fast enough. All studys about NTR's are only speaking about interplanetary vessels.
The Ammonia-Etylen mixture sounds very intresting, but it has to be proven.
Methane-LOX seems to be the easiest way. But a NTR has a nice lifetime cycle of 35 hours (!) at 2600K core temperature. This would enable many missions to various targets with same lander. Chemical engines have lifetime cycle under 1 hour, after 2-3 missions the lander's engine would need intensiv servicing, ofcourse thats cheaper at all than an expensive reactor, but if the mothership is very far and long away from home maybe a better point for the NTR. The reactor weight is lesser than the extra fuel for the pure ch4-lox chemical lander:
empty mass ch4-lox: 19mT
fuel mass: 75mT
total mass 94mT
CH4-NTR:
empty mass 25.5mT
fuel mass 37 mT
total mass 62.5 mT
We need 6,5mT mass for a NTR@250kN thrust, [email protected], 5.5t@182kN, 9t@350kN, 18.5t@1000kN.
So 31.5mT more for the chemical variant. But you are right, i dont' know about its possible to throttle down a NTR savely and fast enough. All studys about NTR's are only speaking about interplanetary vessels.
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