PRELIMINARY DESIGN OF A CUBESAT FOR PLUME SAMPLING AND IMAGING

AT EUROPA

David GAUDIN (1), N. André (1), M. Blanc (1), D. Mimoun (2) (1) IRAP/CNRS-UPS, Toulouse, France (2) ISAE-SUPAERO, Toulouse, France

1. JOINT EUROPA MISSION (ESA Cosmic Vision M5, 2016)

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12U Multi-Mission Platform designed by Students from Supaero

Designed for missions on earth environment : • HESTIA (ONERA + SUPAERO) : Urban heat observation • SPIRou (IRAP + SUPAERO) : Exoplanets detection • ATISE (CSUG Grenoble) : Polar aurora observation

Different configurations considered :

Altitude

100km

<15km

Understand Europa as a complex system responding to Jupiter system forcing, characterize the habitability of its potential biosphere, and search for life.

EPIC: Europa Plume Investigation by Cubesat

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JEM Carrier/Orbiter Study the Europa System at a global scale Interior, Subsurface, Surface, Exosphere, Magnetosphere

Habitability

- Magnetometer, Radio Science - Laser Altimeter - ELS/IMS, INMS, Dust analyzers - Navigation Camera, Radiation Monitor

- 3D Coverage of Europa - Low altitude 100-200 km, near polar circular orbit - Spatial resolution of 10’s km horizontally

EPIC Direct sampling of Europa Plumes Study the moon-magnetosphere interactions, locally Imaging plume sources on the surface of Europa

- Option: EPICom Magnetometer + Electrostatic Analyzer

- Option: EPICam Magnetometer + INMS + Camera

- AOCS for orbit and attitude control - Low periapsis <15km, elliptical orbit - Use JEM as relay - Survivability during eclipses

Environment & Mission Constraints

1. Propulsion

2. Power

3. Radiation

4. Thermal

2. EPIC SCIENCE TRACEABILITY MATRIX

Enabling instrumentation

Science objectives

Constraints on platforms

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Goal Objectives Investigation Measurement requirements Instrument Mission Design

requirements St

udy

the

char

ged

part

icle

s en

viro

nmen

t of

plu

mes

aro

und

Euro

pa

Detect plumes activities at the surface of Europa

Determine the location of plume and their sources, and select the best plume to target (Geophysics, surface/subsurface)

Mapping the surface of Europa and searching for plumes. Wide angle camera (on Orbiter)

Automatic release of the cubesat if the plumes are very short time events. Selection of the Targeted plume on earth and controlled release of the cubesat otherwise. Responsiveness to Plume detection.

Determine the composition of charged particles within the plumes

Determine the Mass And Energy of charged particles (Habitability)

Crossing of the selected plume. Measurements of particle masses from 1u to 60u. Measurements of particle energies from 10eV to 10KeV.

Miniaturized Electrostatic analyzer (on CubeSat)

Orbit with low periapsis (0-15Km) for at least one crossing of the targeted plume. Sampling at the same altitude around Europa to discriminate particles from the plumes and those from others origins.

Detail the interaction between Europa plumes and Jupiter magnetic and gravity fields

Determine how the charged particles within Europa plumes interact with Jupiter's magnetic field (Environment/Magnetosphere)

Measurement of charged particles distribution in the Europa environment. Identification of ion cyclotron waves. Measurement of magnetic field vector and magnitude up to 8000nT with a resolution of at least 0.5 nT.

Miniaturized Magnetometer, Miniaturized Electrostatic Analyzer (on CubeSat)

Measurements of the magnetic field and charged particles during most of an orbit when a plume is crossed and during a complete orbit of Europa around Jupiter.

Caracterise the charged particle environment of Europa from a multipoint perspective.

Caracterise the charged particles Environment from a multipoint perspective (Environment/Plasma)

Measurement of charged particles during several orbits. Measurements of particle masses from 1u to 60u. Measurements of particle energies from 10eV to 10KeV.

Miniaturized Electrostatic Analyzer (on CubeSat and Orbiter)

Measurements of charged particles at an altitude different from JEM

Caracterise the magnetosphere from a multipoint perspective (Environment/Magnetosphere)

Measurement of magnetic field during several orbits. Measurement of 800nT and variations of tens nT.

Miniaturized Magnetometer (on CubeSat and Orbiter)

Measurements of magnetic field at an altitude different from JEM

3. EPICom SCIENCE TRACEABILITY MATRIX

Instrumentation focused on charged particle composition for habitability potential !

4. STRAWMAN PAYLOAD TAILORED FOR EPIC

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EPICom EPICam

5. EPIC MISSION SCENARIO

Mission duration: • 3,5 days (1 complete coverage of Europa’s orbit

around Jupiter) with a possible extension of a maximum of 10 Days after deployment

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Mission profile : • JEM tracking and determination of interesting

plumes via a wide angle camera (max 3,5 days) • Ejection of the CubeSat the nearest possible

of an identified plume (max 1,8 days) • Maneuver to reach the plume at the

periapsides of the orbits (15Km, and lower) • Transmission of the data to JEM thanks to a

S-Band transmitter

Max 4,4°

- Thrust Mode

- Guidance Mode

- Com Mode

- CAM+INMS+MAG

- INMS+MAG

- JEM Orbit

Mission operations

6. EPIC PROPULSION NEEDS

Orbit maintenance :

• Jupiter powerful gravitational field disturbs orbits near Europa. A Delta-V of 0,55 m/s per Day is required for corrections.

Total Needs :

• 3,5 Days -> 79m/s

• 10 Days -> 82m/s

Maneuvers for EPIC: • Plan change maneuver in order to go

through a selected plume • Orbit form change maneuver to a low

periapsides elliptical synchronous orbit with JEM

• Cost in Delta-V : up to 75m/s in worst case

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- High Thrust : 1,25N - High Delta-V capacity : 49m/s (for 24Kg)

- Mass : 1,66Kg - Size : 1U 10*10*11,35 - Temperature : 5-50°C - Low IPS : 235s

Chemical propulsion MPS-130

- High ISP : 1500s - High Delta-V capacity : 243m/s (for 20Kg)

- Dry Mass : 1,4Kg - Size : 1U 10*10*12,5 - Low Thrust : 1,5mN - Power cons. : 25W

Electric propulsion Tile-5000

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eHaWK Solar Array (MMA Design)

Power 4,4W/kg

Gomspace BP4 (GomSpace)

Capacity 38,50 W.h

Efficiency charge/discharge 0,9

Sol

ar P

anel

+

Sec

onda

ry B

atte

ries

Batteries LTC SL-760 (Tadiran)

Specific energy Around 500

Wh/Kg

Max continous discharge curent 100 mA

Weight 18g

Pri

mar

y B

atte

ries

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

20W Solar

20W Battery

15W Solar

15W Battery

10W Solar

10W Battery

Kg

Days

Primary Batteries

Solar Panels

Around 6 Days

7. TRADE-OFF POWER SOURCE

• Thrust Mode (11,5-23,2W) • Guidance Mode (8,9) • Com Mode (6,9W) • CAM + INMS + MAG (15,6W) • INMS+MAG (7,4W)

• Primary Batteries possible

3,5 Day nominal mission

• On Solar panels + Secondary Batteries

10 Day extended mission

8. RADIATION ISSUES

Context :

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Dose for EPIC Duration Dose behind 2,5mm Al (Krad)

min max min max

Interplanetery trip 4,9 Y 0 0

JOI + PRM 6,5 M 0 0

Jovian Tour 9,5 M 124 124

EIO + Ejection to relay orbit

0 0

Lander Relay 34 D 41 D 359 433

Relay to LEO 1 D 3 D 12 36

Tracking of plumes 1,8 D 3,6 D 18,3 36,6

Subtotal with JEM 513,3 629,6

Manœuvre 0 D < 1,8 D 0 18,3

LEOperation Days 3,5 D 10 D 36 103

Subtotal Released 36 111,3

Total EPIC (Krad) 550 751

With

JEM

Re

leas

ed

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Three layers of shielding • The deployer protects the cubesat until an

interresting plume is detected (10 mm) • The external structure of the cubesat (3mm) • Vaults protect more sensitive component of the

cubesat (6mm)

Admissible Radiation Dose • < 150Krad in the CubeSat • < 50Krad in the Vault

Expected Radiation dose (behind 2,5mm of Al) is 750 Krad for 10 day mission

0

29.3

46.9

0

60.0

143.5

0

20

40

60

80

100

120

140

160

Launch of JEM Deployment ofthe CubeSat

CubeSatopération

Radiation inside CubeSat and Vault

Vault CubeSat

9. RADIATION MITIGATION

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10. REQUIRED PLATFORM

Europa Environment Constraints

4. Thermal

2. Power

3. Radiation

1. Propulsion

12U CubeSat • Mass : 24Kg Max

• Size : 218*238*365mm3

14. EPICom / EPICam PRELIMINARY DESIGN

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• Thrusters • Star Tracker • Avionic

PASTELS

INMS

CAM

MAG MAG

• Aluminium Vault • Bloc SCAO

3,5 Day Nominal Mission with

Primary Batteries

3,5 Day Nominal

Mission with Primary

Batteries

10 Day Extended

Mission with Solar Panels

10 Day Extended

Mission with Solar Panels

12. MASS BUDGET – EPICom

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EPICom 3,5 Day Nominal Mission With Primary Batteries

Margin Sub-system Mass (g)

Structure 30% CubeSat MONA 12U Supaéro 2445

Internal Shielding 1636

Propulsion system 30% 2 x MPS 130 Aerojet RocketDyne (1U) 3320

SCAO

AOCS Block

30%

XACT 910

Micropopulsion Vacco 1245

Sun Sensor 5 x Sun Sensor FSS 15

Support Supports 150

AV

Power Supply card

30%

Gomspace P60 286

S-Band 425

Command Data Handling System

Ninano (Steel electronics) 85

Interface 100

Supports and rodes 415

Battery pack 30% 150 x LTC SL760 AA 2700,0

RF S-Band 30% 2 x Syrlinks EWC31 230

Payload

Charged Particles Spectrometer

30%

PASTELS 2860

Magnetometer MAG 104

Boom BOOM MAG 120

Total Mass CubeSat 22,173 Kg Margin Mass (Kg) 1,827 Margin Mass Ratio 8,23% Total Mass CubeSat + Deployer > 32 Kg

Strong constraints for JEM but:

Provides unique Science Returns

Gives opportunity to sample a plume ‘freshly ejected’

Relaxes risks for JEM

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Solar Panels : • Multi-deployable • Radiation Mitigation • Mass optimized structure

Thermal Regulation : • Need of a hot Box ? • Need of MLI, surface coating ?

Deployer for 12U CubeSat

In search of information

SCAO :

• EPICam -> XACT + Micropropulsion + Star Trackers

• EPICom -> XACT + Micropropulsion

Avionics

Mission Profile

To Be Continued

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INMS CAM MAGIC Propulsion 12V

8V

3,3V 5V

3,3V 3,3V 5V 12V

Aluminium Vault

I-] Block Diagram

II-] EPICom PHASE POWER NEEDS

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System Margin 30,00%

Mode Safe Mode Guidance Desaturation Mission mode Com Pre-thrust

Mode Thrust Mode

Thrusters 0 0 0 0 0 1 1 Bloc AOCS Idle 1 1 0,3 0,5 0 1 Micropropulsion 0 0 1 0 0 0 0 Sun Sensor 1 1 1 1 1 1 1 Ninano 1 1 1 1 1 1 1 S band 1 1 1 1 1 1 1 Payload 0 Idle Idle PASTEL + MAG Idle Idle Idle

Total Power Needs with system margin

6,1 8,9 21,7 12,0 6,9 23,2 11,5

III-] SOLAR PANEL STUDY

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Size of a solar cell (cm²) 40,15mm x 80,15mm

Weight of a cell (g) 3,56

Question :

• AOCS powerfull enough ?

Solar flow at Jupiter (W/m²) 51,5

Efficiency of Solar Panel 0,3

Coefficient deterioration due to radiation 0,9

Surface area required (m²) 1,198

Nomber of cells 398

Mass of Solar Cells (Kg) 1,42

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EPICom EPICam

IV-] AOCS