Mass Driver PDRFebruary 25, 2020

Mission Profile (Mars → Phobos)

● Launch windows are defined by phobos

position and tether sling spin up time

○ Phobos must be -29.033° from

Olympus Mons (right ascension)

○ Max turnover = 3 launches/sol

● Acceleration Profile

○ 4.77 km/s Launch Velocity

○ 4.47 km/s Velocity past

atmosphere

○ 2 G’s net

● Total Orbital Flight Time 14.69 hrs

Orbital Trajectory

ΔV (km/s) Time (hrs)

Launch 4.77 6.17

Burn 1 0.286 8.52

Burn 2 0.375 RNDVZ

Total 0.661 14.69

Considerations & Deviations

● Acceleration modification

○ Make time and distance shorter

○ Launch Velocity includes drag and rotation

● Orbital analysis

○ No perturbations

○ No eccentricity/inclinations

● Risk Assessment

○ If launch fails, more ΔV is required

○ If burn 1 fails, the taxi will return to Olympus Mons

○ If burn 2 fails, no return possibility without significant ΔV

Current Mass Driver Design

MagLev System

• Proven to handle loads of our magnitude (passenger trains)

• Allows us to more easily decelerate the cradle for reusability

• Located at the base of Olympus Mons

• Using Null-Flux Coils for Repulsive Levitation

Current Mass Driver Design

Important Parameters

• Track Length: 635 km

• Launch Duration: 4 minutes 14 seconds

• 2g constant acceleration

• F required,propulsion = 6.49 MN

• F required,levitation = 1.1 MN

Candidate Systems

- Propellant saved: 477 Mg

PropulsionForce required: 6.49 MN

Railgun

LevitationForce required: 1.11 MN

Coilgun Maglev

Linear Synchronous

Motor (LSM)

Linear Induction

Motor (LIM)

Wheels Suspended

Electromagnetic

Suspension (EMS)

Electrodynamic

Suspension (EDS)

Mass Driver Technology

z

x

Linear Induction Controller

• Set velocity that is needed to escape Mars(5.03

km/s) Moon(2.38 km/s)

• Sense the velocity of the taxi vs how fast it needs to

have been going

• Increase the current through the LIM to increase

acceleration to needed levels

Journal of Transportation

Force will increase linearly with an

increase in current

Martian Taxi Catching SystemCradle

Information

Mass 100 tons

Material Aluminum 6061

T6

Length 25 meters

Magnet Width 15 meters

Width 36 meters

Mass Driver Materials & Structural Analysis

Mass Driver

Parts

Materials

Rail (EDS system) Iron, Wrought or

Rhenium beams

Vacuum Casing Iron, Wrought

Magnets 15 Lanthanides

Scandium

Yttrium

Niobium Titanium

Structural Integrity Precautions for

Track

• Rounded edges to prevent

cracking

• FEA testing will be conducted

through multiple scenarios (G-

forces, heat, cooldown etc.).

Suggestions needed to increase

reliability.

Power Consumption

Mars The Moon

Peak Power

Consumption (GW)

30.1 13.5

Average Power

Consumption (GW)

14 6.6

Total Energy

Consumption (GJ)

3600 830

● Power consumption peaks at the Taxis top speed when drag force is at a maximum

● Power is stored in batteries and used when solar panels can no longer keep up with the

required power

● VVVF (Variable Voltage, Variable Frequency) power is provided to support the needs of

the MagLev

Power Production and Storage

Mars The Moon

Solar Panel Power (MW) 100 10

Solar Panel Area (km2) .56 .024

Total Mass (Mg) 5500 1100

● Solar Panels provide limited energy and

charge the batteries over the long

duration between sets of launches

● Batteries are capable of holding enough

energy to launch 3 Taxis consecutively

Human Considerations

Forward Acceleration

Backwards Acceleration

7G’s absolute max acceleration (at any given time), 2G’s max sustained

acceleration recommended

Mass Driver Thermal Management• Power Consumption: 30 MW that

needs to be dissipated via Heat

Sinks.

• Due to the amount of heat

generated, the rail will slowly

erode over time, so it has to be

liquid cooled.[1]

Thermal

Systems

(Mars)

Mass Volume Power

Heat Sinks 6.49 Mg 34,285.7

m3

Passive

Cooling

Liquid

Cooling for

the Rail

172.8 Mg 5.1 * 108

m3

230 MW

1. M. Johnson, P. Cote, F. Campo and P. Vottis, "Railgun Erosion Simulator," 2005 IEEE Pulsed Power Conference,

Monterey, CA, 2005, pp. 245-248.

Analysis of Aerodynamic Drag

Aerodynamic Effects

• Max Drag is around 53kN of

force

• Aerodynamic heating is 3.14

GW which would be less than

re-entry heating

• Further analysis is required

based on keeping the magnets

supercooled