Post on 26-Jan-2021
Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Some Applications of Entry Theory• Taking an analytical look at recent* space events • Crossrange and landing opportunities • Ballistic aerobraking
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© 2020 David L. Akin - All rights reserved http://spacecraft.ssl.umd.edu*for suitable definitions of “recent”
http://spacecraft.ssl.umd.edu
Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Washington Post - May 12, 2008
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Soyuz Deorbit Milestones
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Soyuz 5 Reentry
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Soyuz Heat Shield Shape
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d = 2.2 m
depth � 0.3 m
half-angle � 30 deg
R � 2.2 m
Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Soyuz Newtonian Aerodynamics
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Estimation of Soyuz Entry Parameters
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A = �r2 = �(1.1)2 = 3.8 m2
cD � 1.75
� =2900 kg
(1.75)(3.8 m2)= 436
kgm2
� = 4270 Pa
Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Published Flight Characteristics
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Predicted and Published Soyuz Parameters
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�entry = 21.5deg
L
D= 0.27
Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Soyuz Deorbit Reconstruction
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International Space Stationr = 6720 km
v =�
µ
r= 7702 m/sec
adeorbit =�
2ra� v
2
µ
⇥�1= 6510 km
rp = 2a� ra = 6300 km⇥ hp = �78 km
e =raa� 1 = 0.03226
va,deorbit = 7577 m/sec
Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Velocity Components in Orbit (continued)
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Nominal Soyuz Entry Trajectory
Trajectory
020000400006000080000
100000120000140000160000180000200000
0.0 1000.0 2000.0 3000.0 4000.0 5000.0
Trajectory
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Soyuz Trajectory (Ballistic Entry)
Trajectory
020000400006000080000
100000120000140000160000180000200000
0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0
Trajectory
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Nominal Entry Heating and Velocity
0.0
1000.0
2000.0
3000.0
4000.0
5000.0
6000.0
7000.0
8000.0
9000.0
0.0 200.0 400.0 600.0 800.0 1000.0 1200.0 1400.0
TemperatureVelocity
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Ballistic Entry Heating and Velocity
0.0
1000.0
2000.0
3000.0
4000.0
5000.0
6000.0
7000.0
8000.0
9000.0
0.0 200.0 400.0 600.0 800.0 1000.0 1200.0 1400.0
TemperatureVelocity
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
G Loading (nominal entry)
G load
0.0000.5001.0001.5002.0002.5003.0003.5004.0004.5005.000
0.0 200.0 400.0 600.0 800.0 1000.0 1200.0 1400.0
G load
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
G Loading (Ballistic Entry)
G load
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
0.0 200.0 400.0 600.0 800.0 1000.0 1200.0 1400.0
G load
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Published Flight Characteristics
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Cross-Range and G’s vs. Roll Angle
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0
20
40
60
80
100
120
140
0 20 40 60 80 100 120 140 160 180 200
Cross-RangePeak G's
Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Soyuz Landing Ellipse
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0
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140
3000 3200 3400 3600 3800 4000 4200 4400 4600
Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Typical Orbit Groundtrack
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Landing Opportunities - 1200 mi Xrange
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1.2
1.2
Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Landing Opportunities - 300 mi Xrange
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1.2
.6
Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Mars Global Surveyor Aerobraking
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
MGS Multipass Aerobraking
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
(Single-Pass) Aerocapture Maneuver
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Some Applications of Entry Aerodynamics ENAE 791 - Launch and Entry Vehicle Design
U N I V E R S I T Y O FMARYLAND
Ballistic Aerocapture Trajectories
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0!
20000!
40000!
60000!
80000!
100000!
120000!
140000!
160000!
0! 1000! 2000! 3000! 4000! 5000! 6000!
Alti
tude
(km
)!
Downrange Distance (km)!
4 deg!5 deg!5.05 deg!5.10 deg!
ve=10 km/sechap=21,590 km hap=3589 km
hap=1506 km