Mass Driver CDR March 10, 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 Mass Driver Objectives • 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 Mass Driver Objectives • Updated battery sizing, spacing and model • Two 1x1x1 m battery banks every 409 meters down the track Mass Driver Overview Important Parameters • Track Length: 635 km (for taxi + cradle acceleration) 106 km (for cradle deceleration) • Launch Duration: 4 minutes 14 seconds • 2g constant acceleration • Force required: 6.49 MN (propulsion) 1.11 MN (levitation) • Propellant saved: 477 Mg Maglev System Diagram 0.31 m 0.55 m HTS Magnets: 80 magnets total for F = 1.11 MN levitation Coils: 1.6 million coils on each side for 741 km track Superconducting magnet 0.5 m 1.07 m z x Image by Arch Pleumpanya Mass Driver Launch Transition Linear Induction Controller Max Assumed Mass of Cart Time before Max Drag perturbation Voltage and Taxi Liftoff 5.3 kN 100 V 121 tons 254 sec 53 kN Null Flux Controller Frequency of AC current 1 kHz Max amplitude of Current 5.24 * 1015 A Taxi-Grabbing System Image by Erick Smith Taxi Grabbing System Taxi Grabbing Info Tether Length 700 kms Track Diameter 1,394 kms (+- 2 kms) Max Taxis Can 3 Taxis Catch (simultaneously) Olympus Mons 624 kms Diameter Image by Erick Smith Electromagnetic Cradle (EMC) Cradle Information Propulsion Repulsive w/ Wheel Assist Mass 80 tons Material Aluminum 6061 T6 Length 25 meters Height 8 meters Width 30 meters Image by Erick Smith Mass Driver Materials Mass Driver Materials Parts Rail Rhenium beams Magnets HTS Rebco Magnet Coolant Liquid Helium (Cradle) Image by Natasha Yarlagadda Magnet Coolant Freon (Rail) Power Consumption (Single Launch) Mars The Moon Peak Power 43.1 19.5 Consumption (GW) Total Energy 5,220 1,240 Consumption (GJ) ● Power consumption peaks at the Taxis top speed when drag force is at a maximum ● Power during launch is provided by Solar and Batteries ● Magnetic Drag is neglected at both locations ● Air Drag is neglected on The Moon Power Production and Storage (3 Launches) Mars The Moon ● Solar Panel Power is based off a Solar Panel Power (MW) 6.04 1.44 recharge time of one month total for the Solar Panel Area (km2) 0.339 0.0035 three launches ● Solar Panels provide limited energy and Battery Volume (m3) 3.1 * 103 738 charge the batteries over the long duration between sets of launches Battery Mass (Mg) 6,690 1,590 ● Batteries are capable of holding enough Total Mass (Mg) 6,750 1,600 energy to launch 3 Taxis consecutively ● Solar Area on the Moon is much less due to the lack of Air Drag and increased intensity of the Sun Human Considerations Forward Acceleration Backwards Acceleration 7G’s absolute max acceleration (at any given time), 2G’s max sustained acceleration recommended for normal civilian Mass Driver Thermal Management Thermal Mass Volume Power Systems (Mars) Heat Sinks 6.49 Mg 34,285.7 Passive m3 Cooling Liquid 172.8 Mg 5.1 * 108 230 MW Cooling for m3 the Rail Cradle 12.5 Mg 100 m3 769.23 kW System Dylan Pranger 1. M. Johnson, P. Cote, F. Campo and P. Vottis, "Railgun Erosion Simulator," 2005 IEEE Pulsed Power Conference, Monterey, CA, 2005, pp. 245-248. Liquid Helium Thermal Systems Magnet Condenser Vacuum Vacuum Outside Vacuum Dylan Pranger.