AAE450 Spring 2009 Translunar OTV (Orbital Transfer Vehicle) : Chemical Propulsion System Refined estimates: OTV WET Mass, Propellant Volume & Propellant Tank Pressures Week 3 Presentation Thursday, Jan 29, 2009 Saad Tanvir Propulsion Group 1

AAE450 Spring 2009 OTV WET Mass and Propellant Volume Propellant: LH 2 /LOx Engine: HM-7B (Ariane 5 Upper stage) Input Parameters : f inert =0.2, ∆V=4km/s, Isp = 447 sec, O/F=5.14 Saad Tanvir Propulsion Group OTV Wet Propellant mass594 kg OTV Wet mass992 kg Fuel Mass97 kg Oxidizer mass497 kg Volume of Fuel1.26 m 3 Volume of Oxidizer0.44 m 3 2

AAE450 Spring 2009 Pump-Fed System (Gas Generator Cycle) Equation 1 V tank is the volume of the propellant tank P tank is the pressure of the propellant tank Pressure Fuel Tank = 1.04 MPa Pressure Oxidizer Tank = MPa Propellant Tank Pressures Saad Tanvir Propulsion Group Source: Humble, R. W., Henry, G. N., & Larson, W. J. (1995). Space Propulsion and Design. : McGraw-Hill Companies, Inc. 3

AAE450 Spring 2009 Backup Slides: Propellant Choice Saad Tanvir Propulsion Group 4

AAE450 Spring 2009 Backup Slides: HM-7B Engine Parameters Saad Tanvir Propulsion Group 5

AAE450 Spring 2009 Backup Slides: Cost Analysis LOx  Mass LOx: 497 kg  Cost LOx: $95.00 / ton* LH 2  Mass LH 2 : 97 kg  Cost LH 2 : $ 7.17 / kg* Total Cost of Propellant = $743 Saad Tanvir & Brad Appel Propulsion Group *Source: Defense Energy Support Center – FY 2009 Data 6

AAE450 Spring 2009 Back up Slide: Use of Pressure-Fed System  For smaller Tank volumes: P chamber = 3.5 MPa ∆P dynamic = ½ v 2 ~ 0.02 MPa ∆P feed (Upper bound) ~ 0.05 MPa ∆P cool ~ 0.15pc = 0.53 MPa ∆P injector ~ 0.3pc = 1.05 MPa P tank ~ 5.15 MPa Saad Tanvir Propulsion Group Source: Humble, R. W., Henry, G. N., & Larson, W. J. (1995). Space Propulsion and Design. : McGraw-Hill Companies, Inc. 7

AAE450 Spring 2009 Backup Slides: Sizing Code Snap shot Saad Tanvir Propulsion Group 8