EuLISA. <Chemical Propulsion> Internal Final Presentation ESTEC, 8 July Prepared by the ICPA / CDF* Team. (*) ESTEC Concurrent Design Facility

Transcription

1 EuLISA <Chemical Propulsion> Internal Final Presentation ESTEC, 8 July 2011 Prepared by the ICPA / CDF* Team (*) ESTEC Concurrent Design Facility

2 Option 1 First table in MA presentation: Delta-v budget LGA transfer, double launch Chemical Propulsion - 2

3 Option 1 Mother Spacecraft: 1184 kg (dry mass) Daughter Spacecraft: 811 kg (dry mass) Calculate propellant amounts to generate the required ΔVs Assume margins Propulsion system trade off: Monoprop vs Biprop monopropellant resulted in a lighter system (but also cheaper, cheaper to test, etc.) Additional requirements: Preferably European COTS components (LISA Pathfinder propulsion module: biprop system with Eurostar 2000 derived tanks) Single fault tolerant system design Chemical Propulsion - 3

4 Delta-v budget LGA transfer, double launch mother daughter 1 daughter 2 launcher disp 36m/s 5m/s 5m/s perigee raise - 40m/s 40m/s plane change - 11m/s 80m/s apogee raise - 40m/s 40m/s arrival 154m/s 130m/s 104m/s navigation 20m/s 20m/s 20m/s launch window reserve, gravity loss (20%) 42m/s 46m/s 50m/s total 252m/s 272m/s 299m/s Chemical Propulsion - 4

5 Mother S/C option 1 MASSES Spacecraft DRY MASS 1184 [kg] ENGINE CHARACTERISTICS Propulsion type Monoprop Name Hydrazine [-] Propellant density 1010 [kg/m3] Thrust level [N] Number of engines [-] Isp 220 [s] Mass [kg] Mass flow rate [kg/s] VELOCITY INCREMENTS INCLUDING MARGIN Sum of main delta V including margins Steering / AOCS lossed during main Delta V 25.2 Velocity increment (INCLUDING MARGINS) [m/s] Chemical Propulsion - 5

6 Mother S/C option 1 PROPELLANT CALCULATIONS Total propellant for alll velocity increments (including margins excluding residuals) [kg] Additional AOCS propellant 2.0 [kg] Total propellant for alll velocity increments (including margins including residuals) 176 [kg] NUMBER OF TANKS Note: Herschel tanks 2 [-] Propellant mass per tank including margins and residuals 87.8 [kg] Percentage of maximum capacity 68 [%] Propellant volume per tank [m3] Total propellant volume [m3] Chemical Propulsion - 6

7 Mother S/C option 1 Note: Herschel tanks Chemical Propulsion - 7

8 Element 2 Unit Mother S/C Unit Name Click on button above to insert new unit Mother S/C option 1 Part of custom subsystem Quantity Mass per quantity excl. margin MASS [kg] Maturity Level Margin Total Mass incl. margin 1 5 N thruster (MONARC-5 of AMPAC ISP) Fully developed N thruster (CHT-20 of ASTRIUM) Fully developed Propellant tank Fully developed Propellant filter Fully developed Latching valve Fully developed Pressure transducer Fully developed Fill and Drain valve / Vent valve (propellant) Fully developed Fill and Drain valve / Vent valve (pressurant) Fully developed Piping (incl fittings) To be developed Stand-off To be developed Mounting screws To be developed Miscellaneous To be developed Pressurant Fully developed Click on button below to insert new unit SUBSYSTEM TOTAL kg propellant (Hydrazine) Chemical Propulsion - 8

9 Daughter S/C option 1 MASSES Spacecraft DRY MASS 811 [kg] VELOCITY INCREMENTS INCLUDING MARGIN Sum of main delta V including margins Steering / AOCS lossed during main Delta V 29.9 Velocity increment (INCLUDING MARGINS) [m/s] PROPELLANT CALCULATIONS Total propellant for alll velocity increments (including margins excluding residuals) [kg] Additional AOCS propellant 2.0 [kg] Total propellant for alll velocity increments (including margins including residuals) 145 [kg] Chemical Propulsion - 9

10 Daughter S/C option 1 NUMBER OF HERSCHEL TANKS 2 [-] Propellant mass per tank including margins and residuals 72.5 [kg] Percentage of maximum capacity 56 [%] Propellant volume per tank [m3] Total propellant volume [m3] Smaller Seastar tank possible: NUMBER OF SEASTAR TANKS 2 [-] Propellant mass per tank including margins and residuals 72.5 [kg] Percentage of maximum capacity 95 [%] Propellant volume per tank [m3] Total propellant volume [m3] Chemical Propulsion - 10

11 Daughter S/C option 1 Note: Seastar tanks Chemical Propulsion - 11

12 Daughter S/C (option 1) Element 1 Unit Daughter S/C Unit Name Click on button above to insert new unit Part of custom subsystem Quantity Mass per quantity excl. margin MASS [kg] Maturity Level Margin Total Mass incl. margin 1 5 N thruster (MONARC-5 of AMPAC ISP) Fully developed N thruster (CHT-20 of ASTRIUM) Fully developed Propellant tank Fully developed Propellant filter Fully developed Latching valve Fully developed Pressure transducer Fully developed Fill and Drain valve / Vent valve (propellant) Fully developed Fill and Drain valve / Vent valve (pressurant) Fully developed Piping (incl fittings) To be developed Stand-off To be developed Mounting screws To be developed Miscellaneous To be developed Pressurant Fully developed Click on button below to insert new unit SUBSYSTEM TOTAL kg propellant (Hydrazine) Chemical Propulsion - 12

13 - Chemical Propulsion - 13

14 Not considered option Second table in MA presentation: Delta-v budget direct transfer, double launch Chemical Propulsion - 14

15 Not considered option Mother Spacecraft: 1184 kg (dry mass) 252 m/s M D D Propulsion module for 2-Daughter Spacecraft Payload 2 Daughter s/c of 811 kg each (+ propellant) 788 m/s PM Then Daughter Spacecraft: 811 kg (dry mass) 252 m/s Calculate propellant amounts for required ΔVs. Assume margins EuLISA Propulsion Assessment system Study trade off: Monoprop vs Biprop Chemical Propulsion - 15

16 Delta-v budget direct transfer, double launch mother daughter 1 daughter 2 launcher disp 36m/s 5m/s 5m/s perigee raise - 10m/s 10m/s apogee raise - 773m/s 773m/s split - 148m/s 148m/s arrival 154m/s 130m/s 104m/s navigation 20m/s 20m/s 20m/s launch window reserve, gravity loss (20%) 42m/s 218m/s 212m/s total 252m/s 1304m/s 1272m/s Chemical Propulsion - 16

17 - Chemical Propulsion - 17

18 Option 2 Third table in MA presentation: Delta-v budget direct transfer, single launch Basic calculations with basic assumptions Chemical Propulsion - 18

19 Option 2 Mother Spacecraft with biprop propulsion system: 1263 kg (dry mass, including a new biprop system) Generate 788 m/s to itself and the payload (2 daughter s/c on top + propellant for continued mission) D M D Then release 2 x daughter s/c and add 567 m/s to the mother s/c Daughter 1 Spacecraft with high thrust bi-prop system: 832 kg (dry mass, including a new biprop system) 535 m/s (Biprop since requires high thrust and considerable ΔV) Daughter 2 Spacecraft with high thrust bi-prop system : 832 kg (dry mass, including a new biprop system) 503 m/s (Biprop since requires high thrust and considerable ΔV) (assumed same propellant load as daughter1) Chemical Propulsion - 19

20 Delta-v budget direct transfer, single launch mother daughter 1 daughter 2 launcher disp 5m/s 5m/s 5m/s perigee raise 10m/s 10m/s 10m/s apogee raise 773m/s 773m/s 773m/s split 167m/s 167m/s 167m/s arrival 154m/s 130m/s 104m/s navigation 20m/s 20m/s 20m/s launch window reserve, gravity loss (20%) 226m/s 218m/s 212m/s total 1355m/s 1304m/s 1272m/s Chemical Propulsion - 20

21 Mother s/c 1132 kg + (1.2 x 109) kg = 1263 kg Total propellant load 1322 kg Wet mass: 2587 kg Propulsion system 109 kg Daughter s/c 759 kg + (1.2 x 61) kg = 832 kg Total propellant load 166 kg Wet mass: 998 kg Propulsion system 61 kg Option 2 D M D Stack of wet masses: 2587 kg kg +998 kg = 4583 kg Chemical Propulsion - 21

22 Note: Based on LISA Pathfinder Propulsion module (with Eurostar 2000 derived tanks) Resized tanks 2 tanks for daughter S/C 4 tanks for the mother S/C Chemical Propulsion - 22

23 Daughter S/C Option 2 Element 1 Unit - Unit Name Click on button above to insert new unit Part of custom subsystem Quantity Mass per quantity excl. margin MASS [kg] Maturity Level 1 Pressurant tank To be developed Pressurant To be developed MMH tank To be developed MON tank To be developed Propellant residuals To be developed Main engines To be developed RCS thrusters To be developed Gas filter To be developed Pressure regulator (Dual) To be developed Pyro valves (liquid) To be developed Pyro valves (gas) To be developed Latch valves To be developed Non return valves To be developed Fill an drain / vent valves To be developed Propellant filter To be developed Pressure transducer To be developed Pipework To be developed Brackets and mountings To be developed EuLISA - Assessment Click on button Study below to insert new unit Chemical Propulsion - 23 SUBSYSTEM TOTAL Margin Total Mass incl. margin

24 Element 2 - Unit Unit Name Click on button above to insert new unit Mother S/C Option 2 Part of custom subsystem Quantity Mass per quantity excl. margin MASS [kg] Maturity Level Margin Total Mass incl. margin 1 Pressurant tank To be developed Pressurant To be developed MMH tank To be developed MON tank To be developed Propellant residuals To be developed Main engines To be developed RCS thrusters To be developed Gas filter To be developed Pressure regulator (Dual) To be developed Pyro valves (liquid) To be developed Pyro valves (gas) To be developed Latch valves To be developed Non return valves To be developed Fill an drain / vent valves To be developed Propellant filter To be developed Pressure transducer To be developed Pipework To be developed Brackets and mountings To be developed EuLISA - Assessment Click on button Study below to insert new unit Chemical Propulsion - 24 SUBSYSTEM TOTAL

25 Daughter monoprop vs biprop Option 2 Biprop Isp = 321 s 166 kg propellant Monoprop Isp = 224 s 247 kg propellant = 81 kg (in favour of biprop) But this requires larger and heavier tanks, while the savuing on the more simple propulsion system (not even considering the heavier tanks for hydrazine) would be about 20 kg Biprop seems to be the better choice all systems are equal (except for number and length of tanks) Chemical Propulsion - 25

26 Chemical Propulsion - 26