AAE450 Spring 2009 Propellant Choice and Mass Estimates for the Translunar OTV Week 2 Presentation Thursday, Jan 22, 2009 Brad Appel Propulsion Group

AAE450 Spring 2009 Propellant Choice – OTV Main Engine 1.Defining the requirements Deliver 250 kg payload from 200 km LEO orbit to the moon, based on an impulsive-burn trajectory First iteration design based on Delta-II LV 2. Determine feasible options LOx / LH 2 is the only combination which meets the Delta II ’s payload and volume constraints. Brad Appel Propulsion Group Mass of propellant1706 kg Volume of propellant4.45 m 3 Cost of propellant$1800 Total OTV Initial Mass2210 kg Cost of Launch$24 million

AAE450 Spring Requirements for OTV Main Engine Impulsive burn: T/W > 0.3  T > 5 kN Fit inside the LV’s payload fairing Availability, Reliability, and Cost The HM-7B by Ottobrunn is the best candidate Ariane 5 upper stage engine Thrust: 70 kN, Isp: 447 s Length: 1.8 m, Diameter: 1.0 m, Mass: 69 kg Brad Appel Propulsion Group Engine Selection – OTV Main Engine

AAE450 Spring 2009 Backup Slides: Propellant Choice  Constraints: –65% of LV’s payload mass used –40% of LV’s volume used –60% of our volume is tankage  Inputs –delta V = 6300 m/s –inert mass fraction = 0.13  Key Equations : Brad Appel Propulsion Group

AAE450 Spring 2009 Backup Slides: Propellant Feasibility Graph  Adapted from method outlined in Chapter 10 of Space Propulsion Analysis and Design Brad Appel Propulsion Group

AAE450 Spring 2009 Backup Slides: Other Information  Mass LOx: 1462 kg  Volume LOx: 1.28 m 3  Cost LOx: $95.00 / ton*  Mass LH 2 : 244 kg  Volume LH 2 : 3.17 m 3  Cost LH 2 : $3.25 / lb*  Delta II 7920 Cost: $10,692 / kg ** *Source: Defense Energy Support Center – FY 2009 Data **Source: Futron Corporation – 2002 Data Brad Appel Propulsion Group

AAE450 Spring 2009 Backup Slides: Code Snapshot Brad Appel Propulsion Group