LunarDREEM Preliminary Design Report

March 10th, 2005

Source: aerospacescholars.jsc.nasa.gov

Jessica Thompson

Presentation Outline ISOP System

Summary of results from Conceptual Design Report Trade Study Electrolysis System Design Oxygen Storage Tank Design Radiator Design Hydrogen Recycling Trade Study Furnace Design Process for Further Design Iterations

Excavation System Summary of Concepts Analysis of Conveyor Belt Concept Analysis of Drill Concept Bulk Physical Measurement Systems Materials Design Considerations

Jessica Thompson

ISOP System Conceptual Design

heat

Relief valve

System Temperature [K]Pressure [atm]Hydrogen storage

Furnace 1173 1Radiator 360 1

Mass Balance 360 1Electrolyzer 298 1

Oxygen Collection

Conditions

Dependent on future design iterations

Dependent on future design iterations

Conceptual Design Trade Study Results:

•Possible Batch Sizes: 5kg, 10kg, 20kg

•Processing Time: 3 hours

Jessica Thompson

Electrolysis System Slides Space Holder

Alice Zhou

Oxygen Storage Tank Design Assumptions: 3kg oxygen, 20°C operating

temperature, Spherical shape Material Trade Study

Material Yield Strength(Mpa) Density(kg/m3)

Beryllium(pure-toxic?) 350 1850Aluminum 48.3 2768Super alloyxm-19 127 7750 High strength annealedAluminum5052 H38 44 2685Haynes188 103 8968Aluminum Tread-Brite H18 27 2740.3Monel K-500 65 8442.3

Becca Arvanites

Calculating Tank Mass Oxygen Pressure = mass*R*Temp/Volume Radius = [(3/4pi)*Volume]1/3

Tank wall width = Pressure*Radius/Max yield stress Tank mass=Density*Surface area*Width

=Density*4pi*Radius2*WidthMaterial Tank Mass(kg)

Beryllium(pure-toxic?) 36.2Aluminum 39.4Super alloyxm-19 41.8 High strength annealedAluminum5052 H38 41.9Haynes188 59.8Aluminum Tread-Brite H18 69.7Monel K-500 89.2 Becca Arvanites

Oxygen Tank Results Lightest (allowably safe) material Aluminum,

still much too heavy Looking into alternative composite material Should reduce weight of tank by 37%+

39kg to less than 25kg

Becca Arvanites

Radiator Study Purpose

To find a suitable length and mass for a radiator to condense Heated Water Vapor (900oC) to Condense Water Vapor (95oC)

Assumptions Total incoming flow value, min will be .002 kg/s

The heat that is released by the water vapor is conducted by aluminum and emitted to space, thus we will calculate the power emitted to space per unit area exposed to the surroundings.

Temperature of the surroundings will be 40 K Efficiency of the radiator will be around 90%

James North

Radiator Study First, the thickness of the aluminum must be found since we

know that the heat generated by radiation should be equal to the heat generated by conduction.

The aluminum tubing will be cover with Multi Layered Insulation which will allow for the use of MLI’s thermal conductivity to be used to find the thickness.

Thickness = -K∙( Tsurroundings - Twater)/[ε∙σ∙(Twater4 – Tsurroundings

4 )]

Thickness = 1.055 x 10-5 m

James North

Radiator Study Calculations

Iteration process of ΔT = 1 as T > 95oC (368 K)

Power/Area = ε∙σ∙(Twater4 – Tsurroundings

4 )

Cp=143.05 - 183.54∙(T/100).25 + 82.751∙(T/100).5 - 3.6989∙(T/100)

Length=[min∙Cp*(T - ΔT )] /[η∙2∙π∙router∙(Power/Area)]

Mass=ρ*π*(router 2-rinner

2)∙Length

James North

Radiator Study

0 200 400 600 800 1000 12000

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

Temperature [K]

Leng

th [

m]

Length of the Radiator versus Temperature

0 200 400 600 800 1000 12000

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1x 10

-3

Temperature [K]

Mas

s [k

g]

Mass of the Radiator versus Temperature

Length = .1772 m Mass = 8.06 x 10-

4 kg James North

Radiator Study Must taken into consideration lunar regolith covering the

MLI during operations Assume the efficiency of the radiator to drop to 80% Outside regolith may adversely affect the temperature of condensed

water vapor exiting the radiator Very important to not have that temperature bet 0oC

James North

Radiator Study

η = .9

T= 5oC Length = .1956 m

T= 95oC Length = .1772 m

η = .8T= 5oC Length = .2201 mT= 95oC Length = .1993 m

Operating Length will be .2 mOperating Mass will be 9.09 x 10-4 kg

James North

Trade Study on Recycling Hydrogen Hydrogen mass flow: H2

tank-->Furnace--> (with water vapor) through radiator--> Electrolyzer-->Recycling tubing-->Pump

mass flow=.01kg/s, flow velocity=.01m/s

H2

O2

Furnace Electrolyzer

Mass flow=.02kg/s

Mass flow=.0198 kg/s

Flow v >.01m/s

Becca Arvanites

Hydrogen Furnace Flow Needed to check flow velocity >.01m/s in

furnace: Area = mass flow/(density*velocity) for mass flow of .02kg/s: Area < 22m2 for flow velocity = .08m/s: Area=2.78m2

Chart Title

0

5

10

15

20

25

0 0.02 0.04 0.06 0.08 0.1

Velocity (m/s)

Fu

rnac

e A

rea

(m^

2)

Series1

Becca Arvanites

Hydrogen Recycling H2 Recycling to reduce tank weight

H2 mass(no recycling)=flow rate*3hours*(#batches)>1000kg

Returning hydrogen includes H2 and hydrogen from water vapor, mass flow=.0198kg/s

For Radius of4.5cm,Velocity is35m/s

Hydrogen Return Area

0

0.002

0.004

0.006

0.008

0.01

0 50 100 150 200

Flow Velocity (m/s)

Are

a (m

^2)

Series1

Becca Arvanites

Hydrogen Recycling Circulating mass H2=H2 flow rate*time

time=distance/flow velocity each section=5.11s H2 mass = 0.102 kg

Weight of Recycling system =length*pi*width2*densityaluminum

Weight=4.254m*pi*(.005^2)*2768=0.926kg

Becca Arvanites

Furnace Heating Trade Study: Heating Method

Electrical Resistance Furnace

Microwave Furnace

RHU Technology Based Furnace

JoHanna P.

Furnace Heating Trade Study: SummaryFurnace Design Type

Electrical Microwave RHU

Pros: - Ability to adjust heat output (i.e. to reach and maintain a constant temp)

- Ability to adjust heat output (i.e. to reach and maintain a constant temp)- More even distribution of regolith heating than electrical furnaces- More efficient than electrical furnaces

- Heating units are very light

- Requires no power from the rover or lander

- RHUs are space proven technologies

- Design can be specific for this application

Cons: - Currently poor estimate for sizing and power requirements

- No method for better estimation in the foreseeable future

- Not designed for space and never used in space

- Currently no information on sizing and power requirements

- No method for better estimation in the foreseeable future

- Not designed for space and never used in space

- Continuously outputting heat

- Must design furnace from scratch

- Potential for this to not be feasible

JoHanna P.

Furnace Heating Trade Study: RHU Technology Based Furnace Calculations based on Cassini RHU

Performance Characteristics Mass/RHU: 40g Thermal Power @ BOL: ~1W

Additional assumption: 80% of the heat generated reaches the regolith

Results: Less than 2.3kg of RHU mass required for the option requiring the highest power levels (10kg batch with a 1hr heating time).

JoHanna P.

RHUs will continuously output heat; thus, heating the inside of the furnace after the regolith has reached the desired temperature.

RHUs will radiate heat in all directions. RHU geometric distribution around the regolith will

impact regolith temperature distribution. Regolith heating characteristics will impact regolith

temperature distribution.

Furnace Heating Trade Study: RHU Technology Based Furnace Design Considerations

JoHanna P.

RHU Technology Based Furnace: 0th Order Structural Mass Calculation

Assumptions Uniform wall thickness of 1/16 in (0.159cm) Wall material is Ti-6Al-4V Spherical furnace

Equation Mass = density * thickness * inner surface area

ALtm 2***

ALtm 2***

JoHanna P.

Place Holder for Parametrics Furnace Mass Curve

JoHanna P.

ISOPS Design Flow Chart

Radiator – mass flow rate (kg/s)

Hydrogen gas flow requirement (Allen and McKay)

Batch Size in Furnace

Furnace hydrogen mass flow (kg/s)

Furnace Cross-sectional Area

Hydrogen-recycling trade-study

Electrolyzer Design

Oxygen Tank Design

Given: Design Calculations Yield:

*What we have shown today is the first iteration through this design process

JoHanna P.

Presentation Outline ISOP System

Summary of results from Conceptual Design Report Trade Study Electrolysis System Design Oxygen Storage Tank Design Radiator Design Hydrogen Recycling Trade Study Furnace Design Process for Further Design Iterations

Excavation System Summary of Concepts Analysis of Conveyor Belt Concept Analysis of Drill Concept Bulk Physical Measurement Systems Materials Design Considerations

Jason Atkins

Excavation System Includes:

Excavator Subsystem to collect regolith Bulk Physical Characteristics Test Chamber Delivery System to transfer regolith from Excavator

Subsystem to ISOPS We discuss preliminary designs for the Excavator

Subsystem and Bulk Physical Characteristics Test Chamber Shape and orientation of Bulk Physical Characteristics

Test Chamber constrain choice of Delivery System

Jason Atkins

Excavator Subsystem Concepts Conceptual Design Trade Study identified

two promising concepts: Conveyor Belt Drill

Jason Atkins

Place Holder for Conveyor Belt Slides

Jason Atkins

Drilling: Power Considerations

Constraints: Drill depth at least 1 meter

deep. 100 kg of Lunar Regolith

must be collected. Maximum Power Usage=

100 W

Emmanuel Sin

Drilling Strategy The Drill will have a

cutting edge that will allow it to cut into the Lunar Regolith.

As the Drill moves downward, soil will travel up through the flights.

“Peck-drilling” will prevent the flights from filling up with soil and thus prevent the Drill from getting stuck.

Emmanuel Sin

Drill Concept

Although the drill length is constrained to 1m, certain drill specifications can be manipulated to optimize excavator efficiency:

- Drill diameter- Flight design (quantity, angle, width)- Cutting edge- Material selection

Emmanuel Sin

Drill: Power Calculations P= F*V P= T*W

Requires experimental data!

Emmanuel Sin

Mass vs. Number of Holes

0

10

20

30

40

50

60

0 5 10 15 20 25 30

Number of Holes

Mas

s of

Dril

l + C

olle

ctio

n B

in Series1

Drill: Mass Calculations

Zachary Reynolds

Drill: Operational Time

Drilling time vs. number of holes

0

5

10

15

20

25

0 5 10 15 20 25 30

Number of Holes

Tota

l dril

l tim

e (h

ours

)

Series1

Zachary Reynolds

Calculations Number of holes to drill-> radius of each hole

-> torque required to drill hole of this radius-> necessary inner radius of drill to bear such a torque -> mass of drill

Assume torque required is proportional to cube of radius of hole

Assume 100W motor ~2 kg (http://scootersupport.com/motors.htm)

Zachary Reynolds

Electra Lazer DP SpecificationsTwin Serrated Stainless Steel Lazer

Blades 12 Volt Battery Pack

12 Volt Battery Charger External Battery Cables

190-200 RPM Cutting Speed 20 Amp Draw

Optional extensions available for cutting through ice thicker than 42“

Electra Lazer 12000 DP 5" 26 Lbs. Electra Lazer 12000 DP 6" 27 Lbs. Electra Lazer 12000 DP 7" 28 Lbs. Electra Lazer 12000 DP 8" 29 Lbs.

Source:

http://www.strikemaster.com/electra.html

Commercially Available Ice Auger

Zachary Reynolds

Bulk Physical Measurement Systems Three Concepts:

Compression Chamber Rotary Bar Pin Pull

Jordan Medeiros

Compression ChamberShear Compartment

Compressive Piston

Shear Line

Shear Piston

Mode of Operation:• Sample is loaded into the chamber and compressed to a desired

displacement by the compressive piston. The force required to reach such a displacement is backed out by taking the voltage applied by the actuator to the piston.

• A voltage is then applied to the second actuator controlling the shear piston. This voltage is slowly increased until a displacement occurs along the shear line. This voltage represents the force required to yield the material.

• Using a set of such measurements, we can construct a stress-strain curve for the material and back out other physical characteristics as well.

Jordan Medeiros

Rotary BarViscosity Tester

Compressive Piston

Rotary Bar

Rotary Piston

Mode of Operation:• Sample is loaded into the chamber and compressed to a desired

displacement by the compressive piston. The force required to reach such a displacement is backed out by taking the voltage applied by the actuator to the piston.

• A voltage is then applied to the second actuator controlling the rotary piston. This voltage is slowly increased until a displacement occurs along the rotary line. This voltage represents the force required to yield the material in shear.

• Using a set of such measurements, we can construct a stress-strain curve for the material and back out other physical characteristics as well.

Jordan Medeiros

Pin PullIndentation Test

Compressive Piston

Indentation Pin

Mode of Operation:• Sample is loaded into the chamber and compressed to a desired

displacement by the compressive piston. The force required to reach such a displacement is backed out by taking the voltage applied by the actuator to the piston.

• A voltage is then applied to linear actuator controlling the movement of the indentation pin. By comparing the voltage used (which correlates to force), the area of the pin head in contact with the sample, and the depth of the indentation, we can find characteristics such as material hardness using the same methods applied in nano-indentation applications.

Jordan Medeiros

Bulk Physical Measurement Systems

Pros All the systems require very few moving parts, significantly lowering the chance of failure All the systems require very few sensors to back out the required data All the systems work in any scale, allowing for flexibility in design

Cons Both the viscosity tester and indentation system are prone to a problem known as frame compliance – the frame of

the testing unit, being of finite stiffness, undergoes a displacement when placed in a state of stress. This must be accounted for by calibrating the test unit.

Since it is not known what is the required force to shear the material it is difficult to determine certain design factors – The power of the motors driving the pistons, the required frame material stiffness, etc.

These systems do not get direct measurements of the desired characteristics – these must be found using raw data and calculation software.

Jordan Medeiros

Other Considerations: Bulk Physical Measurement Systems Primary factors Affecting physical properties

of lunar regolith: Particle structure and distribution Bulk density and porosity Relative density

Etienne Toussaint

Other Considerations: Bulk Physical Measurement Systems Particle structure and distribution

Variable that controls to various degrees the strength and compressibility of the material

The structure and void ratio of the particles can be altered through the excavation process While in the test chamber, the particle structure will directly

impact the relative density of the regolith and how easy it to compress it or conduct the rotary tests

All concepts will alter the particle structure during the compression test, which may make it harder to conduct the test for shear force using the rotary bar and wire pull

Etienne Toussaint

Other Considerations: Bulk Physical Measurement Systems Bulk density and porosity

The mass of the material within a given volume and the volume of void space between particles Directly related to particle distribution – if the regolith is densely

packed in test chamber with little porosity (would probably occur using drill which grinds soil), bulk density will be high and force required to move the rotary bar or to compress the soil will be great

Conversely, soil that not as fine, or possibly deposited in clumps (tread system) may be more porous and thus, not as dense. Less force will be required for compression and the bar test

Etienne Toussaint

Other Considerations: Bulk Physical Measurement Systems Relative density

Again, bulk density of a given soil can vary over a wide range, depending on how particles are assembled Should take into account when doing various

calculations – various ranges of densities possible.

Etienne Toussaint

Bulk Physical Measurement SystemsAnalysis of positive & negative affects of physical properties of

lunar regolith on conceptual designs  

Conceptual Design Particle structure/distribution Bulk density/porosity Relative density Total Affect

Compression Chamber -1 0 0 -1

Rotary Bar 0 -1 -1 -2

Thin Pin Pull 0 -1 -2 -3

Etienne Toussaint

Bulk Physical Measurements Excavation System

The drill will grind the regolith into small particles as it moves deeper into the ground, decreasing the amount of void space between particles and thus increasing the relative density. This will directly effect the force needed to move through the

soil and it will cause the soil to be more dense when it is deposited in the test chamber

The tread system will pick up the soil in small chunks, maintaining a more realistic depiction of the density of the soil in the ground. Less problems related to relative density will come into play using this system.

Etienne Toussaint

Preliminary Materials SelectionConditions to be taken into consideration: Extremely low temperature

Temperature in shadowed crater assumed to be 40ºK Extremely low pressure

Atmosphere assumed to be hard vacuum Abrasive soil

Regolith’s abrasiveness is comparable to that of glass

Victoria Harris

Preliminary Materials SelectionLubricants1

Choose interfacing materials that have different crystal structures and atomic sizes

Wet lubrication Oils will most likely not work in low temperatures

Dry lubrication Some work in low temperatures (eg molybdenum

disulfide) Shorter service life

Victoria Harris

Preliminary Materials SelectionMetals2

Most metals will work E.g. stainless steels, aluminum alloys Exceptions include nickel steels

Some material properties will change at low temperature E.g. coefficient of friction

Composites are also a possibility

Victoria Harris

Preliminary Materials SelectionInsulation/rubber Rubber suitable for constructing a conveyor

belt will not withstand low temperatures3

Other belt designs must be investigated Typical insulators used in cryogenic

applications can be applied E.g. ethylene-propylene4

Victoria Harris

Bibliography1. Virgil R. Friebel and James T. Hinricks. “Lubrication for

vacuum applications.” Journal of Vacuum Science and Technology. January 1975. Volume 12, Issue 1, pp. 551-554.

2. JG Weisend, ed. Handbook of Cryogenic Engineering. Hamburg, Germany: Taylor and Francis, 1998.

3. www.mcmaster.com4. Atsushi Minoda and Yasuichi Mitsuyama. “AC Treeing of

Ethylene-Propylene Rubber in Cryogenic Temperature Region.” Electrical Engineering in Japan, Vol. 124, No. 3, 1998.

Victoria Harris

Outreach Update

Julie Arnold

Ordering Laboratory Materials

Julie Arnold