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CubeSat-sized Re-entry Capsule
MIRKA2
M. Ehresmann, A. Behnke, J.-P. Baumann, R. Tietz, J. Franz,
D. Galla, B. Gäßler, F. Grabi, F. Hessinger, R. Hießl,
M. Koller, G. Kuhn, N. Müller, R. Müller,
A.Papanikolaou, J. Rieser, V. Schöneich,
H. Seiler, M. Siedorf, V. Starlinger, A. Stier,
A. Tabelander, F. Vardar, S. Wizemann,
A. S. Pagan, G. Herdrich,
R. Laufer
Manfred Ehresmann ehresmann@ksat-stuttgart.de
10th IAA Symposium
21/04/2015
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Outline
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Mission Overview
CubeSat Atmospheric
Probe for Education
C. Montag, Session 7
Planetary Probe Design Workshop:
Collaboration Hands-On Small Satellite
Training for Engineering Students
R. Laufer, Session 7
A Service and Deorbit Module for
CubeSat Applications
M. Ehresmann, Poster Session 1
Programme Announcements:
CAPE Mission Patch
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Shape
• Adapted shape of
flown probes
→ Known flight
characteristic
• COG 45% x-axis MIRKA2 Dimensions
Deep Space 2 ReBR RED-Data2 MIRKA2
Mass [kg] 2.4 4.4 1.65 0.45
Max.Diameter [cm] 35 31 20 10
Table 1: Capsules with same Shape
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Inventory
• COTS paradigm coin for scale
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Inventory
Heat shield Small diameter → high expected heat loads
Very compact → high expected heat loads
Small nose radius → high convective stagnation
point heat flux
• Ablation Heat shield necessary
Candidates: RICA, ZURAM
RICA Sample
ZURAM
→ MIRKA2 is a test bed for
ablation materials 12MW/m² for 15s
14MW/m² for 22s
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Inventory
MIRKA2 Surface Sensor Arrangement
Scientific Payload
• Thermocouples
→ Heat Flux
→ Recession Rate
→ Flow Characteristic
• CN- Radiometer
→ Plasma composition
• IMU/GPS
→ Position and Attitude
• Pressure sensors
→ Flow Characteristic
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Inventory
Iridium QB9603
Communication
Sensor output rate: 84 Bps
Storage needed during blackout phase
• Iridium QB9603 Transmitter
Frequency: K-Band (1616 - 1626MHz)
Nominal data rate: 125 Bps
Effective short burst data rate: 35 Bps
→ Reduced sampling frequency
→ Prioritizing of data
→ on-board processing
Iridium & GPS Antenna
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Analysis
Tool: REENT
Initial conditions:
Determined by SDM
𝑣0 ≈ 7.54 km/s
𝛥𝑣𝑠𝑒𝑝𝑎𝑟𝑎𝑡𝑖𝑜𝑛 ≈ 0.54 m/s
γ ≈ 0.05°
h ≈ 120 km
(i ≈ 51.6°)
Fig 1:Trajectory MIRKA2
Baumann, Pagan, Herdrich:
Aerothermodynamic re-entry analaysis of
the cubesat-sized entry vehicle MIRKA2 → Long Reentry Duration
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Analysis
Specific enthalpy to
dissipate
ℎ𝑠 = 28.44 MJ/kg
Peak heating at 70 km
→ 𝑞𝑘𝑜𝑛𝑣 ≈ 2.5 MW/𝑚2
Conservative
assumptions
→ fully catalytic surface Fig 2: Convective heat flux Stagnation point MIRKA2
→ High Heat Flux
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Analysis
• Long reentry
duration
• High heat flux
Q ≈ 500 MJ/m²
Fig 3: Integral heat load MIRKA2
→ High Integral heat load
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Action Items
• Mission analysis Service and Deorbit Module → flight path angle ↑,
𝛥𝑣𝑠𝑒𝑝𝑎𝑟𝑎𝑡𝑖𝑜𝑛↑, apogee perigee control
• Heat shield Configuration
→ insulation, varying thickness
• Custom printed circuit board
→ OBC costs few hundred €
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Outlook
• Verifying electric system, communication, flight stability • Launch March 2016 Kiruna, Sweden
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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The End
Thank you for your attention!
KSat Team Beginning 2015
21/04/2015 CubeSat-sized re-entry Capsule
MIRKA2 www.ksat-stuttgart.de
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Le Backup
4/20/2015 MIRKA2-R Experiment 16
Flight Stability of the Capsule
• DLR, Supersonic and Hypersonic Technology Department [2]: • Aerodynamic investigations
→Confirmation of expected flight stability of the Mars Microprobe
Mars Microprobe [1]
• Mars Microprobe [1]
• Applied for ReBR and RED-Data2 • Allows stable flight • Deceleration down to subsonic speed • Requirement: Centre of gravity between
38% and 56% of total length from nose tip →Passive stabilisation enabled
Appendix
• Reentry Breakup Recorder (REBR) [3, 4]: • 3 successful flights • Transmission time of > 260 s with Iridium • After orbital return deceleration to subsonic speed • ballistic coefficient β=55.4 kg/m² • Centre of gravity: <56 % of total length from nose tip
• RED-Data2 [3, 4]: • Smaller version of REBR • Communication: Iridium • Ballistic coefficient β=42.9 kg/m² • Centre of gravity: 52% of total length from nose tip
→MIRKA2-R • Miniaturisation for CubeSat application (Iridium/Globalstar) • Ballistic coefficient β=50.4 kg/m² • Centre of Gravity: < 52% of total length from nose tip → Similar properities compared to ReBR and RED-Data2
Communication of the Capsule
4/20/2015 MIRKA2-R Experiment 17
Communication for existing ballistic capsules:
Dimensions in mm of ReBR and RED-DATA2 [4]
Diameter of MIRKA2-R capsule: 100 mm
Appendix
Design of the Experiment • MIRKA2 Capsule Data Budget
4/20/2015 MIRKA2-R Experiment 18
Datatype Amount of
Values [-] Bytes
Amount of
Sensors [-]
Sampling Rate
[Hz]
Total
(Bps)
Start integer 1 2 1 1 2
Thermocouple float 1 4 6 1 24
Battery
Voltage float 1 4 1 1 4
Radiometer float 1 4 1 1 4
Pressure float 1 4 2 1 8
IMU float 6 24 1 1 24
GPS float 4 16 1 1 16
End integer 1 2 1 1 2
Total (Bps) 84,00
Appendix