SPACECRAFT PROPULSION - KTH

More documents

Recommendations

Info

- 49 -Fig.17, has to be considered in addition to the propellant storagesystem as already dealt with for chemical propulsion systems.To describe the performance of electric propulsion systems, thedenominator of Eq. (22) has to be further determined. Both, the massof the propellant storage system and the mass of the electric powersupply system have to be considered.For systems operation with gaseous propellants, e.g. xenon, thecombined mass of tank and propellant is calculated according to theEq. (28) as derived for cold gas systems above. The mass of theelectric power supply and processing system is calculated with thesystem specific power W/kg:where:Pm El (43)v eP F(44)2is the system input of electrical energy and = P jet /P is the overallenergy conversion efficiency.With Eqs. (29), (43) and (44) the combined mass of the propellantstorage system and the electric power system is calculated forsystems operating with gaseous propellants:mPSS mEl mHW mP mT mEl mHW zRT Fve mP1 1 KM mP2x(45)
- 50 -The system-specific impulse becomes with Eqs. (22) and (45):IsspmP mTItot mEl mHW1zRTKMveFve 1mP2x(46)And for:mPFt F (47)v veewith t =, which is the thruster operating time (s), the system-spec.impulse for ELECTRIC <strong>PROPULSION</strong> SYSTEMS, operating withgaseous propellants, becomes finally:Issp1zRTKMve2v e 12x(48)Eq. (48) shows that the I ssp for electric propulsion systems dependson the parameters of propellant storage as well as on the energysupply and processing systems. According to Eq. (48), for highvalues of I ssp , high values of v e and low values of x are required.However, with regard to the impact of the energy supply andprocessing system on the I ssp , low values of v e and high values of γand as well as long thrust operation times τ are preferred. Withregard to the controversial requirement for v e , there must be optimalvalues of v e-opt , which will result in maximum values of I ssp .
Page 6 and 7: -iv -Standard NotationsStandard not
Page 8 and 9: - 1 -1 INTRODUCTIONThis booklet sum
Page 10 and 11: - 3 -The main features of jet propu
Page 12: - 5 -This expresses that the spacec
Page 17 and 18: - 10 -3.2.3 Evaluation of Mass of P
Page 19 and 20: - 12 -With regard to the system-spe
Page 21 and 22: - 14 -According to Fig. 3 and with
Page 23 and 24: - 16 -Historically, chemical propul
Page 25 and 26: - 18 -gases leave the outlet of the
Page 27 and 28: - 20 -The vaporising liquid system
Page 30 and 31: - 23 -Further, for vaporising liqui
Page 32 and 33: - 25 -ConclusionAlthough of moderat
Page 34 and 35: G- 27 -4.2.3 MonopropellantMonoprop
Page 36 and 37: - 29 -System-specific Impulse, I ss
Page 38 and 39: - 31 -Table 4: Ranges of typical Pr
Page 40 and 41: - 33 -4.2.4 BipropellantBipropellan
Page 42 and 43: - 35 -management devices), propella
Page 44 and 45: - 37 -From Eq. (41) it is obvious t
Page 46 and 47: - 39 -4.2.5 General System Design C
Page 48 and 49: - 41 -System-specific Impulse, I ss
Page 50 and 51: - 43 -4.3 Electric Propulsion4.3.1
Page 52 and 53: - 45 -To the above described catego
Page 54 and 55: - 47 -4.3.2 Propulsion System Desig
Page 58 and 59: - 51 -The term of an optimal exhaus
Page 60 and 61: - 53 -resulting in a maximum value
Page 62 and 63: - 55 -Table 8 notes the differences
Page 64 and 65: - 57 -5 PROPULSION SYSTEMS SELECTIO
Page 66 and 67: - 59 -m PS/m S/C1,0I ssp=193 Ns/kg(
Page 68 and 69: - 61 -In considering the merits of
Page 70 and 71: - 63 -Table 11: Survey: Typical Can
Page 72 and 73: - 65 -6.1 Potential Improvement of
Page 74 and 75: - 67 -6.2 Potential Improvement of
Page 76 and 77: - 69 -6.3 New ApproachesNew approac
Page 78 and 79: - 71 -Extensive research has been p
Page 80 and 81: - 73 -8 MISSION SURVEILLANCE OFPROP
Page 82 and 83: - 75 -[9 W. Inden; “Development R
Page 84: Notes

SPACECRAFT PROPULSION - KTH

Create successful ePaper yourself

Delete template?

Save as template?