Section I PresentationsMarch 6, 2020

Nick Rich February 13, 2020

Project ManagerProject Schedule and Updates, Report

Requirements

Project Schedule, PDR ReviewSchedule

March 28 – Design Freeze, Report Outline

Week of March 10, 12 – CDR

March 26 – Action Item Closeout

April 3 – Rough Draft Due, Revisions Begin

April 9 – Final Report Due

April 16 – Dry Run Presentation

April 23 – Final Presentation

PDR Review – Going into CDR

March 13 – Action Item Assignment

Week of March 24, 26 – Writing Workshop

Week of March 31, Apr 2 – Writing Workshop 2

• PDR went exceptionally well! All designs

are nearing a completed state.

• Moving forward, emphasize configuration,

orientation, and interaction.

• Final mass, power and volume numbers

should be set within a 10% range.

• All the aforementioned should be nearly

finalized.

• All CAD models should look as real as

possible – designs should have no more

placeholders or generic “space grey”

coloring.

• Animations should be in work or completed.

Animations/Sims Needed for CDR and Final Pres.

- ED Tether Spin up and launch (scaled down)

List of Animations

- Cycler rotation and vehicle movement (with and

without taxis)

- Mass Driver Launch

- Taxi re-entry profile, Mars

- Cycler docking taxis

Report Info

- Tether operation for each location (Luna, Phobos,

Mars) – rendezvous closeup included

- Landing track use once Martian tether spins down

- Communication Satellite movement to

illustrate zero outage

List of Simulations

- All legs of the mission from Earth LEO to Mars

touchdown and vice versa

- Cycler orbit over time

- Macro scale depiction of taxi rendezvous with

other systems

- If you think of other things that could be

animated/simulated, add to “List of Animations” in

PM/APM folder on Drive.

- Writing workshops to come after Spring Break.

- Make sure that you’re hanging on to all the

analysis you do. Everything that we have

investigated will go into the report in some way.

Sodiq AdenijiMarch 5, 2020

Discipline: CADVehicle & Systems Group: Tether Sling

Tether SystemsObjective: To provide a visualization of the Tether Sling & ED - Tether

Requirements:• Phobos Tether Sling (Base Design): Design 80% Complete

• Luna Tether Sling

• Has crawler/gondola system attached.

• Hollow torque arm to provide access to the hub center.

• All Tether Slings

• A design on taxi docking mechanism.

• A more realistic look and a sense of scale.

• Design on support structure and anchoring system.

Additional Items:• Started compiling animation sequences.

• Need to start creating individual and integrated animations of the system.

Tether Sling (Current Model)

Tether Sling (Isometric)Animation Work in Progress

Scale 1:10000

Tether Sling (Exploded View)

Burj Khalifa 828 m

Motor-Hub System

Hanson-Lee Harjono March 5, 2020

Discipline: CADVehicle: Communication Satellites

Communications Satellites Dimensioning & Sizing

L4/5 Satellite Frame Dimensions

Created by Hanson-Lee Harjono - CAD

Component Mass Volume

Stationary Orbit

Satellite Frames

2.043 Mg 0.754 m^3

L4/5 Satellite Frames 2.384 Mg 0.88 m^3

GEO Solar Panels 0.246 Mg 0.091 m^3

AREO Solar Panels 0.464 Mg 0.171 m^3

L4/5 Solar Panels 0.478 Mg 0.176 m^3

Modeled Masses and VolumesDrafting Diagrams

Satellite Rendering

GEO Satellite Rendering by Hanson-Lee Harjono, CAD

Next Steps:

Solar panel – Satellite frame connection

RF Dish – Satellite frame connection

Telescope – Satellite frame joint

Telescope length with mirror

Internal layout

Work out masses and sizes

Megan BrownMarch 5th, 2020

Area: Communications

Systems: Ground StationsCycler RF Antenna

CONTINUOUS COMMUNICATION ON THE CYCLER

Customer Requirements:

• Continuous Line-of-Sight between RF antenna on cycler and receiver on taxi

CAD and Image Credit: Aaron Engstrom

RF antennae will be on

either end of the cycler’s

superstructure on

opposite axes, to ensure

no blockage and

continuous line of sight.

CONTINUOUS COMMUNICATION FROM GROUND STATIONS TO RELAY SATELLITES

New Earth Ground Station:

New Lunar Ground Stations:

Location Antenna Diameter Power Required

UNSW, Sydney, Australia 22 meters 0.59 Watts

This location in Australia allows us to have a ground station on either side of the globe, ensuring

complete line-of-sight to all relay satellites in GEO.

Location Antenna Diameter

North Pole of the Moon 10 meters

Phobos 10 meters

These locations ensure direct

line-of-sight to relay satellites in

GEO and at different Lagrange

points.

Alex MooreMarch 5, 2020

CommunicationsTaxi

Problem

• How does the radome material affect the link budget?

• How does the TPS affect the link budget?

• Requirements

• 4 dB gain margin

• < 1kW transmission power

• Minimum range: 16,000 km

• (Maximum theoretical distance from Taxi to

Phobos)

Solution

• Quartz fibre composite radome with TPS

• Radome path loss

• Dominated by TPS interference, not Quartz fibre

• 2 dB loss during spaceflight [2]

• Blackout is likely during reentry due to ionization

Parameter Internal Antenna

Mass [1] 1.25 kg

Power [3][4] 328 W

Diameter 0.5 m

Receiver Maximum Range

Phobos Ground Station 89,000 km

Cycler 30,000 km

BREAKResume at 2:10

Alexander James ChapaMarch 5, 2020

Vehicle Controls: Tether Sling and Mass Driver

The Problem: We Need a Controller to Catch a Taxi With the Tether Slings

Assumptions:

• The tether will spin with a constant angular

velocity unless a torque is applied.

• All excess stress felt by the crew is dampened.

• Max torque available in 16GNm

• Reference frame is stationary.

• The Tether is already spun up 0.0385𝑜/𝑠Goals:

• To be able to meet the taxi with a tether arm as

it flies by

• Can adjust itself to taxi trajectory

Illustrations by Alexander Chapa

Conclusion

I am able to catch the taxi

with the tether; however, this

would require a 28-hour

notice from the taxi for where

it will rendezvous.

I will debug the controller

itself and working on ways to

reduce the required call

ahead time

Riley FranklinMarch 6th, 2020

Discipline: ControlsSystems: Cycler

Cycler Attitude Controller

Problem: Verify the attitude control system for the cycler.

Requirements:

• Control for angular velocity.

• Ensure that the angular velocity never varies from the required value for 1 g

of acceleration.

• Model perturbations and observe response.

Need to Find:

• What kind of controller to use.

• Method of modeling cycler.

Results• Controller based off of change of angular velocity through accumulation of angular momentum

• Fairly quick response time.

• Verified performance with randomized torques simulating unexpected for perturbations.

Sarah CulpFebruary 13, 2020

Human FactorsCycler and Taxi: Systems Integration and Additional

Safety Considerations

• Cycler: Advanced Closed Loop System (ACLS) and Bioregenerative Life Support

System (BLSS)• How are the ACLS and BLSS integrated? [2]

The Problems: Systems Integration and Safe Noise Levels

• Taxi: Proton Exchange Membrane (PEM) Fuel Cell and Crew Water Consumption • Can we entirely depend on water generated by the PEM Fuel Cell to provide for human

needs? [1]

1

2

• Both: Safe Noise Requirements• Any sounds above 82 dB (over the course of 150

days) can cause permanent hearing loss

• Noise levels above 68-70 dB cause headaches

• Sources: • Launch/ Entry

• Carbon Dioxide Removal Assembly (75.5 dBA),

flight hardware (75 dBA), Waste Management

Noise Requirement Level

Continuous Noise 58 dBA (Max)

Intermittent Noise (<=8

hours)

49 dBA (Max)

Sleep Noise Level 50 dBA (Max)

Launch / Entry 105 dBA (Max)

Word Intelligibility 78% (Min)

3

[1] Dean Lontoc, Taxi Power and Thermal

[2] Alexey Zenin, Cycler Human Factors

The Solution:

1

ACLS Per Cycler Module

Mass (Mg) 1.47

Volume (𝑚3) 5.4

Power (kW) 2.83

2

3

PEM Fuel Cell

+ 49.09 kg

H2O

Potable H2O

Storage Tank

Daily

Consumption

- 48 kg H2O

Wastewater

Storage Tank

H2

O2

Auxiliary Supply

Taxi: PEM Fuel Cell and Crew Water Consumption

• Entirety supplied by PEM, Safety Factor of

1.2 requires auxiliary supplyWater System Per Taxi (5 Days)

Mass (Mg) 0.360

Volume (𝑚3) 0.439

Power (kW) *In PEM Analysis [1]

+ 9.6 kg

• Auxiliary ACLS systems: supply ¼ of the required O2

and ¼ required N2 (3 units per cycler module)

• Assume 75% crop yield (~1.2 Safety Factor)

Cycler: ACLS and BLSS

Both: Noise Mitigation Noise

Mitigation

Taxi

(24 people)

Per Cycler

Module

Mass (Mg) 0.032 0.072

Volume (𝑚3) 0.966 2.28

• Entry/Launch: Active Noise Reduction Headsets

• Continuous Noise: Sound absorptive linings

surrounding historically loud systems

David FoxMarch 5, 2020

Discipline: Human FactorsVehicle: Cycler

The Problem

Entertainment (cont.):

- Different ways of stimulating senses

- Easy communication with people on Earth

Maintenance:

- Need tools on cycler for Intravehicular

Activities (IVA) maintenance [1]

Housekeeping:

- Ways of keeping cycler clean for

long health of crew [2]

Drawing created by David Fox

Current Solution

Component Count Mass [kg] Power [kW] Volume [m3]

Computers/desks 4 79 0.26 1.76

iPad Pro 70 44.1 1.26 (while

charging)

0.025

Playing cards/board games 8 7.5 0 0.05

Maintenance IVA tool kit 2 77 0 0.15

Housekeeping items -- 56.4 2.4 (2 vacuums

in use)

0.466

Kait HauberMarch 5, 2020

Human FactorsMicrobiome, Med Bay, Quarantine

Human Factors

Requirements:

● Understanding of microbes that may become malign in microgravity or

irradiated conditions

● Assessment of supplies, devices, and logistics for medical bay

countermeasures

Assumptions/Constraints:

● General lack of understanding of radiation effects outside of Earth’s

magnetic field

● Microgravity only needs to be considered for short taxi flight

Need to Determine:

● Quarantine procedures for illness or psychosis

● Layout of med bay

● Inclusion of new vaccines or antibiotics for microbes that may be

terrestrially benign

Problem: Precautions and equipment needed for pathogens and surgical/public health concerns

3-5% of

population

General

anxiety

45% of

anxiety

cases

Severe

1-2 people will

experience a panic

response

Human FactorsConclusions:

● Space panic and illness will be an issue in taxi

● Need studies on different microbes outside of

magnetic field in order to prepare

● Lab to perform diagnostic testing

● Need to bring medical gases (nitrous oxide)

● Dental procedures

● Only need to be able to quarantine 2 people

Nitrous Oxide Container Specs:

- Volume: 0.7 m3

- Mass: 30 kg

Operating table

Me

d

Ga

s M

edic

al S

upplie

s

Bed Bed

Fluid Management

Lab

Wo

rkbe

nch

Health Monitoring

Kaitlyn Hauber, Purdue University

BREAKResume at 2:44

Jennifer Bergeson

March 5, 2020

Discipline: Mission DesignVehicles and Systems: Cycler Orbit, Phobos

Tether Effects

The Problem: Determine Propellant Equivalent Delta V and Feasibility of Phobos Use

ΔV saved by tethers: Impact of tether on Phobos:Assumptions: Assumptions:

Any launch/return plane available Tether mass concentrated at 𝑟

3

Propulsion has Martian orbit to surface propellant Tether & Phobos axes aligned

Requirements: Requirements:

No use of tether Determine if Phobos will be despun

Find ΔV for each segment Determine if Phobos will explodeMarsTaxi

Earth

Cycler

ω

TaxiTether

Phobos

Numerical Results

Taxi Segment Average ΔV for Each

Segment (km/s)

LEO to Cycler (outbound) 4.30

Cycler to LMO (outbound) 3.18

LMO to Cycler (inbound) 2.80

Cycler to LEO (inbound) 4.88

Taxi Segment Max ΔV for Each

Segment (km/s)

LEO to Cycler (outbound) 4.65

Cycler to LMO (outbound) 3.83

LMO to Cycler (inbound) 3.55

Cycler to LEO (inbound) 5.18

ω𝑝ℎ𝑜𝑏𝑜𝑠 = 1.823 ∗ 10−4𝑟𝑎𝑑

𝑠ω𝑒𝑠𝑐𝑎𝑝𝑒 = 2.23 ∗ 10−3

𝑟𝑎𝑑

𝑠

Jordan CuellarMarch 5th , 2020

Mission DesignTether Sling

The Problem: Feasibility of Earth-Mars Transfers from Tether

Requirements:

• ∆𝑉 ≤ 5𝑘𝑚

𝑠

• Reasonable TOF (less than 1 year)

Assumptions:

• The Sun is the only force during

interplanetary trip.

• Moon/Phobos gravity ignored within

Earth/Mars systems.

Need to Determine

• ∆𝑉 from Moon and Phobos tether for each

part of the voyage.

Solution and Results

• 6 and 8 Month trips without passengers

from Earth to Mars are possible with

current tether design.

Trip and TOF Phobos ΔV

(km/s)

Luna ΔV (km/s)

Earth-Mars 6

Months

1.28 2.80

Earth-Mars 8

Months

2.22 2.57

Mars-Earth 6

Months

5.50 8.07

Mars-Earth 8

Months

5.49 7.35

Nicolas Martinez CrucesMarch 5, 2020

Mission DesignTether Sling

Problem & Assumptions

Requirements• Getting payload/passengers from sling

to hub

• Define forces involved in this process

• Time of transport

Assumptions• Docking velocity

• Mars = 5 km/s

• Luna = 2 km/s

• Elevator velocity 150 m/s

• No drag included

Need to Determine• Velocity at each radial point of tether

• Centripetal forces at each point

• Time on elevator

Limitations

• Forces dependent on mass

• Tether lengths TBD

• Docking velocity TBD

Solution

Source [1]

Suhas AnandMarch 5th, 2020

Power and ThermalMass Driver

Liquid Helium Cooling System for the CradleThe Problem:

Magnets need to be cooled at 10K

Need to Determine:

Method of Cooling

Coolant Type

Mass, Power, Volume

Credit: Erick Smith

Coolant Type Coldest Liquid Temperature

R-134a 293 K

Liquid Nitrogen 78 K

Liquid Helium 4 K

Cradle Thermal SystemVacuum Sealed Thermal System helps

reduce conductive and convective heat

generation.

Magnet

Va

cu

um

Liquid Helium

Ou

tsid

e

Vacuum

Con

de

nser

System Specifications Values

Mass 25,000 kg

Volume 200 m3

Power 700 W

Vincent Bartels March 05, 2020

Power & Thermal Group LeadSurface (Phobos, Moon, Mars) Tethers

Problem: That’s a lot of heat

Focus: Further refine power supply and determine configuration & size of system

necessary to dissipate heat generation

Objectives:

- Find best type & shape of radiator

for motor heat dissipation

- Find operating temp of solar panels

- Determine its configuration relative

to other components

- Slowly eliminate arrays of

possibilities

Array Size (km²) based on GW req

20 40 60 80 100

169.90 339.81 509.71 679.61 849.52

155.34 310.68 466.02 621.36 776.70

321.71 643.42 965.13 1286.84 1608.55

Array Size (km²) based on MW req

20 40 60 80 100

0.17 0.34 0.51 0.68 0.85

0.16 0.31 0.47 0.62 0.78

0.32 0.64 0.97 1.29 1.61

Radiation Needs & Sizing

Motor Heat Rejection Based on Power Req

Mech (MW) Overall (MW) Heat Rejection (MW)

20 20.14 0.14

40 40.28 0.28

60 60.42 0.42

80 80.56 0.56

100 100.70 0.70

Motor: AC HTS

Ma

in c

oo

lant

flow Heat Pipe

Carbon Fiber Fins

Figure based on diagram from [9]

Heat Dissipation

Peak Efficiency Temp (°C) 28.00

Actual Temperature (°C) 86.60

Solar Cells: SpectroLab XTE-HF (32.1%)

Heat Sources

Radiator Length Based on Surface Temp (m)

Power Reqs (MW)

Temp (deg C) Emissivity 20 40 60 80 100

400 0.74 16.37 32.73 49.10 65.46 81.83

600 0.78 5.48 10.97 16.45 21.94 27.42

800 0.79 2.37 4.75 7.12 9.49 11.87

Radiator Diagram Full System View

BREAKResume at 3:20

Yashowardhan GuptaMarch 5, 2020

System: ED TetherDiscipline: Power and Thermal

Power Management

Problem:

Preliminary Sizing of the power and transmission

system

Approach:

1. Research on transmission efficiencies and power

loss

2. Preliminary sizing of the Solar Arrays

High Power system

Generation

Eclipse Time Considerations

Size and Mass Constraints

Efficiency Constraints

Transmission

Power Loss

Current and Voltage

Limitations

Heating Effects

Storage

Heating Effects

Size and Mass Constraints

Power (MW) Voltage (kV) Current (A) Examples

496.9

20704.2 24 14 AWG

Most Common in Households14614.7 34 12 AWG

9555.8 52 10 AWG

1806.9 275 3/0'Heavy Duty Wires

1325.1 375 4/0'

100 4969.0

HV Transmission (High Voltage)500 993.8

800 621.1

1,000 496.9

UHVDC1,100 451.7 China (Maximum) with 12 GW Power

1,400 354.9

[1]

[2]

Solar Array Sizing and Transmission Selection

Power Required

(MW)Solar Array Type

Solar Array

EfficiencyTransmission Efficiency

Power Produced

(MW)

Solar Array Size

(km2)Mass (Mg)

496.9

IMM-α Space

Solar Cell32%

92.08%

1686.4 1.233 604.1

MonoCrystalline

Silicon 20% 2698.2 1.973 966.5

PolyCrystalline

Silicon16% 3372.7 2.466 1208.2

HVDC vs HVAC

Advantages Disadvantages

30 – 40% more efficient

(Low Power Loss)

Costlier till 600 kmBetter Voltage

Regulation

Lower Communication

Interruption

Future Considerations:

1. Eclipse time losses

2. Battery Sizing

3. Size will decrease once batteries

included and idle charge time calculated

4. Thermal Problem

PartAltitude

(km)

Low Activity

Temperature

(K)

High Activity

Temperature

(K)

Mean

Density

(kg/m3)

Taxi

Caught356 700 1615 8x10-12

[3]

[4]

[5]

[6]

[7]

Solar Intensity (W/m^2)

1367.9

Chuhao DengMar 05, 2020

PropulsionCommunication Satellites

RCS for Communication Satellites

Precise Attitude Control:

• Reaction wheels and four 3-way RCS for precise attitude control

Existing Syste𝒎[𝟏]:

[1]: W. R. Mickelsen, Future Trends in Electric Propulsion, AIAA Paper , 66-595, 1966

3-Way RCS (Dimensions and

shapes are based on the design)

Fuel Analysis for Tether Sling on Mars

42

48

54

57

91.8

0 10 20 30 40 50 60 70 80 90 100

HTPB

NTO/Aerozine 50

LOX/RP-1

NTO/MMH

LOX/LH2

Mass Ratio

Chem

ical P

ropella

nts

Mass Ratio of Tether Sling to Chemical Propellants (Mars)

Code provided by Shuting Yang

Kristen FleherMarch 5th, 2020

PropulsionED Tether

Electrodynamic Boost of LEO Tether

The ED system has to boost the

momentum bank and tether sling back to

the 928 km orbit.

The entire ED length must be applied in

one direction since the force results from a

cross product.

The ED portion should not be the driving

physical dimension

The momentum bank momentum of inertia

shall equal the tether/taxi moment of inertia

Quantity Value

Taxi Mass 182 Mg

Velocity to Taxi 3.46 km/s

Tether Length 573 km

Tether Mass 19,827 Mg

ED Length 1,278 km

ED Power 461 MW

ED Boost Time 3 days

Electrodynamic Wire Configuration

Split into 2 disks to keep symmetry around

tether.

The necessary moment of inertia of the

momentum bank is much greater than the

moment of inertia of these disks.

The radius of the disk is much smaller than

the current torque arm length.

Quantity Value

Number of Disks 2

ED Disk Radius 156 m

Spacing Between Wires 3x wire radius

Effective ED Length 1,278 km

Adam BrewerMarch 5, 2020

Discipline: StructuresSystem: Phobos/Luna Tether Slings

Torque Arm Sizing

Problem: Determine the length of the torque arm on the

Phobos and Luna tether slings

Assumptions:

• Maximum acceleration of 2 g’s

• Tether radius decreases linearly along length

• 10 m2 solar panels = 1 kW

• Maximum linear tip velocity = maximum ΔV

Requirement

• Generate enough torque to spin the taxi under all

conditions

HubTorque arm

Taxi

Image by Adam Brewer. Not to scale.

Torque Arm Sizing

Location Tether

Length (km)

Maximum

ΔV (km/s)

Solar Array

Area (km2)

Torque Arm

Length (km)

Phobos 700 3.7053 509 17.6

Luna 1352.9 5.1521 366 2.7

Conclusion:

• Phobos torque arm is 17.6 km

• Luna torque arm is 2.7 km

• Discrepancy mostly arises from Luna’s longer tether—results in a

lower RPM/higher torque

Eric Eagon March 5, 2020

Structures TeamCycler Vehicle Interior Structure/

GCR Radiation Protection

Cycler Vehicle- Interior Structure

The Problem:

Cycler must protect the habitants from Galactic Cosmic Radiation (GCRs), prepare

for Solar Energetic Particles (SEPs) and maintain structural integrity.

Requirements:

• Cycler must attenuate radiation exposure to 0.5 Sv/year [1]

• Cycler interior must maintain rigidity under centripetal and pressure forces

Assumptions/Constraints:

• Center wall in habitation hallway acts as structural support (multi-cell section)

Needs to Determine:

• Interior wall material and thickness

• New structural mass

Cycler Vehicle-Interior Structure Solution:

• Aluminum 7075-T6 used for hull

• High density Polyethylene foam

behind habitation hull.

Conclusions:

• GCR radiation will reduce by about

6% [3]

• Best location for SEP shelter would

be elevator stations with thickest,

densest hull [1]

• Aluminum hull can handle pressure

and structural loads with a safety of

factor of 5 [2]

Updated Cycler Structural Mass

Hull Thickness [m] 0.15

Polyethylene Thickness [m] 0.5

Mass [Mg] 7556

Cross-Sectional view of cycler habitation module