1. Week 4 Presentation Thursday, Feb 5, 2009
Orbit Transfer Vehicle Electric Propulsion System: High-Level Analysis and Component Specifications
Week 4 Presentation
Thursday, Feb 5, 2009
Brad Appel
Propulsion Group 1

2. Electric Propulsion System Analysis
Determine a performance range for mission feasibility
Choose a thruster for the X1 design
Hall thruster BHT-1500 from Busek will satisfy the requirements
EP system is in general modular  good for scaling
System Property
Desired Range
Mission Constraint
Thrust mN
TOF < 1 year
Specific Impulse
> 1500 s
Reduce IMLEO
Power Input
< 5 kW
Reasonable solar array size
Brad Appel
Propulsion Group 2

3. Propulsion System Components
Xe Tank
Pressure Regulator
Mass Flow Controller
FVV
Hall Thruster
Power Processing Unit
From Power Distribution Unit
X1 OTV Propulsion System Component Breakdown
Component
Mass [kg]
Dimensions [m]
Cost [$ US]
Power Req. [W]
Source
Hall thruster BHT-1500
5.7
0.23 x 0.23 x 0.20 (box)
230,000
1,670
Busek
PPU Assembly
8.3
0.40 x 0.45 x 0.15 (box)
690,000 --
Xenon Feed System
1.6
(plumbing and valves)
Busek (Moog PFCV)
Contingency Mass
3.1
Xenon Propellant 85
0.051 m^ sphere diam = 0.46 m
300
DESC
Tank 21
sphere diam = 0.47 m
TOTAL
124.7
1,150,300
Brad Appel
Propulsion Group 3

4. Backup Slides: EP Performance Comparison
Brad Appel
Propulsion Group 4

5. Backup Slides: EP Performance Comparison
Brad Appel
Propulsion Group 5

6. Backup Slides: Fundamental Equations
Ideal rocket equation for propellant mass:
Specific power of overall spacecraft:
Mass of spherical tank:
Brad Appel
Propulsion Group 6

7. Backup Slides: Other Information
Density Supercritical Xe: 1673 kg/m3
Cost Xe: $ 5.00 / liter*
Assumptions for sizing code:
Delta V = 8 km/s
S/C specific power = 65 W/kg
Payload = 250 kg
*Source: Defense Energy Support Center – FY 2009 Data
Brad Appel
Propulsion Group 7