1. Week 6 Presentation Thursday, Feb 19, 2009
Translunar Orbit Transfer Vehicle (OTV): Updates in Sizing and Optimization Mass Comparisons of Available Hall Thrusters
Week 6 Presentation
Thursday, Feb 19, 2009
Brad Appel
Propulsion Group 1

2. OTV Sizing: Joint Effort with Mission Ops Group
Trading between many parameters: Time of flight, thrust, specific impulse, mass flow rate, power, propellant mass, and cost
Currently a TOF of 351 days provides the cheapest mission, but the story drastically changes if the solar panel price varies
Brad Appel
Propulsion Group 2

3. Comparison of Different Hall Thruster Systems
Updated OTV Numbers
Based on BHT-1500:
TOF = 351 days
Initial Mass [kg]
660
Power Required [W]
2574
Xenon Mass [kg]
170
Tank Diameter [m]
0.58
TOF = 186 days
Initial Mass [kg]
598
Power Required [W]
6817
Xenon Mass [kg] 90
Tank Diameter [m]
0.47
Brad Appel
Propulsion Group 3

4. Backup Slides: Optimum Isp for our Mission
Note: Curve not steep: Can tolerate s with only 6% loss
Brad Appel
Propulsion Group 4

5. Backup Slides: Various Empirical Curves
Brad Appel
Propulsion Group 5

6. Backup Slides: OTV Scaling Up
Scaled up the GLXP design according to payload mass fraction and specific power, normalized to the maximum payload capacity of each launch vehicle. Worked with Power Group.
Launch Vehicle
IMLLO [kg]
Dnepr
2,511
1,808
Falcon 9
5,363
5,137
Ares V
80,660
77,264
Method 1
Method 2 (Use this)
Brad Appel
Propulsion Group 6

7. Backup Slides: Other Information
Density Supercritical Xe: 1673 kg/m3 (P = 150 bar)
Cost Xe: $ 5.00 / liter* OR $1200 / kg**
Assumptions for sizing code:
Payload = 290 kg  Probably larger now (~315)
OTV Structure/Thermal Mass = 120 kg
Launch cost to LEO 400 km: $5000 / kg (roughly extrapolated from $3400 / kg to 200 km)
*Source: Defense Energy Support Center – FY 2009 Data
**Source:
Brad Appel
Propulsion Group 7