Avionics, Software, and Simulation
Doug Astler
Alex Krajewski
Chris O’Hare
Dennis Sanchez
Crew Capsule Selection
• Team C4’s crew capsule was selected
because it has no external elements,
which leaves room for sensors
• It also has the highest mass margin, we
therefore have the most available sensor
mass total to work with
Link Budget
Communications link budgets were created for the following links. A safety
factor of 2 (3 dB) is used for determining transmitter size and power.
Band Transmitter Receiver
Distance
range (km)
Use Scenario
Ku
Spacecraft
Earth
station
2k – 384k
LEO, Transit, Lunar
orbit
Ku
Spacecraft
Relay sat
384k
Transit relay
Ku
Relay sat
Earth
station
448k
Transmission relay
Ka
Spacecraft
L2 Relay
sat
64k
Lunar orbit/landing dark side
S
Spacecraft
Earth
Station
2k – 384k
LEO, Transit, Lunar
orbit
UHF
Spacecraft
EVA suits
< 10
Space, lunar EVA
Link Budget - Receivers
The spacecraft will make use of different receivers during the mission;
• Deep Space Network
• Provides continuous possible coverage from three stations
• Large dishes can pick up weak signals
• Has some no-coverage spots within 30,000 km altitudes
• TDRSS
• TDRSS can relay transmissions to grounds stations
• Useful if DSN is not available
• No atmospheric concerns for signal
• L2 Relay satellite
• A theoretical satellite in the L2 Lagrangian point will help maintain
continuous communication during orbital and lunar surface times on
the dark side of the moon
• This will be modeled as a TDRSS satellite
• EVA suits
• Communication must be maintained with crew during all EVA
missions
Link Budget - Receivers
This table represents the relevant statistics of the various receivers
used in this mission.
Dish size (m)
Max Distance
(km)
Bands
supported
DSN
34
384k
Ku, S
TDRSS
4.9
384k
Ku
L2 Relay
(TDRSS)
4.9
65k
Ka
EVA
N/A
10
UHF
Link budget - Diagrams
(1)
(2)
(3)
(4)
Spacecraft to DSN
Spacecraft to TDRSS
Spacecraft to L2 relay satellite
L2 Relay sat to DSN/TDRSS
Link Budget - Spacecraft
• To minimize transmitter mass and size, one transmitter dish will
be used for all three bands considered
• This will limit communications to only one link at a time
• Size and power requirements will be dictated by the band with the
greatest requirements (in bold)
Spacecraft
To DSN
To TDRSS
To L2
Ku
S
Ku
S
Ka
Transmitter
Antenna Diam
(m)
0.10
0.10
0.1
0.25
0.10
Transmitter
Power (W)
0.09
7.55
4.15
15.5
0.05
Link Margin
(dB)
3.23
3.02
3.05
3.1
3.03
Link Budget – Relay Sat
• The L2 relay sat antenna size is being modeled on
TDRSS
• We assume that it must reach earth from the L2
Lagrangian position
L2 Satellite
To DSN
To TDRSS
Ku
Ku
Transmitter Antenna Diam
(m)
4.9
4.9
Transmitter Power (W)
0.001
0.04
Link Margin (dB)
12.72
3.07
Link Budget - UHF Omni
• UHF omni antenna will be used for both space and
lunar EVA
• Maximum EVA distance is 10 km (Apollo legacy)
Spacecraft
To EVA Suits
UHF Omni
Transmitter Power (W)
0.001
Link Margin (dB)
4.39
Link Budget – Final Stats
These are the final stats, that will drive the size
and maximum power draw of the transmitters.
Antenna
Ka, Ku, S band
UHF Omni
Diameter (m)
0.25
N/A
Max Power (W)
15.5
0.001
Link Margin (dB)
3.1
4.39
Different Bands of Frequency
Microwave Frequency Band
Band
Frequency Range
L band
1 to 2 GHz
S band
2 to 4 GHz
C band
4 to 8 GHz
X band
8 to 12 GHz
Ku band
12 to 18 GHz
K band
18 to 26.5 GHz
Ka band
26.5 to 40 GHz
Q band
30 to 50 GHz
U band
40 to 60 GHz
V band
50 to 75 GHz
E band
60 to 90 GHz
W band
75 to 110 GHz
F band
90 to 140 GHz
D band
110 to 170 GHz
Transmitter
Due to the small transmitter being used, signal beams will be narrow.
This necessitates accurate transmitter pointing.
Ka
Ku
S
λ (m)
0.009375
0.025
0.12
θ (deg)
2.14
5.72
27.5
θ = λ/𝐷
Transmitter
Transmitter will be mounted on a 2 DOF rotational mount
• Provides 2π steradian coverage
Spacecraft will contain 2 transmitters at opposite sides
• Minimizes spacecraft attitude maneuvers to send a
transmission
• Provides redundancy in the event of a transmitter failure
Different Bands of Frequency
EU, NATO, US ECM frequency designations
Band
Frequency Range
A band
0 to 0.25 GHz
B band
0.25 to 0.5 GHz
C band
0.5 to 1.0 GHZ
D band
1 to 2 GHz
E band
2 to 3 GHz
F band
3 to 4 GHz
G band
4 to 6 GHz
H band
6 to 8 GHz
I band
8 to 10 GHz
J band
10 to 20 GHz
K band
20 to 40 GHz
L band
40 to 60 GHz
M band
60 to 100 GHz
Sensors
Information Needed
Type of Sensor(s) Needed
Example
Attitude dynamics
Rotary position sensor,
position sensor, and
acceleration sensor
Star Tracker
Pressure in the cabin
Pressure sensor
MPL115A
Temperature in the cabin
Temperature Sensor
DS18B20
Oxygen and Carbon Dioxide
levels in the cabin
Oxygen sensor and Carbon
Dioxide sensor
TR250Z and Dynament
Radiation levels in the cabin
Radiation Sensor
Geiger Counter
Docking and landing
Proximity Sensors
E2EM
System deployment (landing
gear)
Electric Power monitoring
equipment, Proximity sensor
KM50-E and E2EM
System and Electronic
functioning
Electric Power monitoring
equipment
KM50-E
Propulsion tank leakage
Liquid Leakage Sensor
K7L-AT50/ -AT50D
DS18B20 Programmable Resolution 1-Wire Digital
Thermometer
DS18B20 Programmable Resolution 1-Wire Digital Thermometer
• Provides 9-bit and 12-bit Celcius temperature
measurements
• Accuracy of ± 0.5°C in range of -10°C to 85°C
• Accuracy of ± 2°C in range of -55°C to 125°C
• Operating temperature range
• -55° to 125°C
• Power Supply
• 3.0 – 5.5 Volts DC
• Current Consumption
• 1 to 1.5mA DC
DS18B20 Programmable Resolution 1-Wire Digital Thermometer
• Sampling Rate
• Temperature conversion times
–
–
–
–
9 bit resolution = 93.75ms
10 bit resolution = 187.5ms
11 bit resolution = 375ms
12 bit resolution = 750ms
• Signal Band
• Max can be is 1.3 GHz for signal output
• Criticality
• Used to check internal temperature of crew system vehicle to
make sure it is around room temperature for crew
• Ensures astronauts are safe
DS18B20 Programmable Resolution 1-Wire Digital
Thermometer
MPL115A Digital barometric pressure sensor
MPL115A Digital barometric pressure sensor
• Measures an absolute pressure range of
• 0 – 115 kpa
• Accuracy of ± 1kpa in range of -20°C to 85°C
• Operating temperature range
• -40°C to 105°C
• Power Supply
• 2.4 – 5.5 Volts
• Current Consumption
• Sleep Mode = 1μA
• Active = 5μA at one measurement per second
MPL115A Digital barometric pressure sensor
• Sampling Rate
• 1 measurement per second
• Signal Band
• Max can be is 8 MHz for SPI timing component
• Criticality
• Used to check internal pressure of crew system
vehicle to make sure it is safe for crew
• Ensures astronauts’ safety during the mission
TR250Z Oxygen Sensor
TR250Z Oxygen Sensor
• Measures O2 in a range of 0 to 25% or 0.1
to 95%
• Accuracy of ± 0.5% (2% full scale)
• Operating temperature range
• -10°C to 70°C
• Power Supply
• 24 V DC ± 10%
• Current Consumption
• 600 mA @ 24V DC
TR250Z Oxygen Sensor
• Sampling Rate
• Sampling is done by diffusion with (ZrO2)
Zirconium dioxide
• 4 sec max diffusion time
• Signal Band
• 13.8 GHz to 14.7 GHz
• Criticality
• Used to check internal levels of oxygen of crew
system vehicle to make sure the crew can breath
DYNAMENT CARBON DIOXIDE INFRARED
SENSOR
DYNAMENT CARBON DIOXIDE
INFRARED SENSOR
• Measures CO2 in a range of 0 to 1000ppm up to
0 to 5% volume CO2
• Accuracy of ± 1% measuring range
• Operating temperature range
• -20°C to 50°C
• Power Supply
• 3V to 5V DC
• Current Consumption
• 60 mA
• Response time of <30 sec in 20°C
DYNAMENT CARBON DIOXIDE
INFRARED SENSOR
• Sampling Rate
– Response time <30 sec in 20°C temperature
• Signal Band
• Source drive frequency:
– 2Hz minimum
– 3Hz typical
– 4Hz maximum
• Output signal is around 15 MHz
• Criticality
• Used to check internal levels of carbon dioxide of crew
system vehicle to make sure the crew does not suffer carbon
dioxide poisoning
MLX90316 Rotary Position Sensor
IC
MLX90316 Rotary Position Sensor IC
• Absolute rotary position IC with Magnetic design
• Measures from 0 to 360 degrees
• Voltage Requirement
• 4.5-5.5 V
• Has a 10V voltage protection
• Current Consumption
• Slow mode = 8.5-11 mA
• Fast mode = 13.5-16 mA
• Temperature Range
• -40°C to 150°C
MLX90316 Rotary Position Sensor IC
• Sampling Rate
• Slow mode = 600 μs
• Fast mode = 200 μs
• Signal Band
• Slow mode = 7 MHz
• Fast mode = 20 MHZ
• Criticality
• Used to measure the rotational position of the
spacecraft during attitude dynamics
Bosch Sensortec BMA180 Digital
triaxial acceleration sensor
Bosch Sensortec BMA180 Digital
triaxial acceleration sensor
• Three axis accelerometer with integrated temperature
sensor
• ultra-low noise and ultra high accuracy
• Programmable g-ranges (1g, 1.5g, 2g, 3g, 4g, 8g, 16g)
• Zero-g Offset
• ±5 to 60 mg
• Voltage Requirement
• 4.25 V
Current Consumption
• For sleep mode to low noise mode  0.5-975 μA
• Temperature Range
• -50°C to 150°C
Bosch Sensortec BMA180 Digital
triaxial acceleration sensor
• Bandwidth
• High pass = 1Hz
• Band pass = 0.2 – 300 Hz
• Sampling Rate
• 1200 samples/sec
• Signal Band
• Noise density @1200Hz, 2g, 150-200 μg/√Hz
• Input runs on 7.5-10 MHZ
• Outputs data at 2400-1200 Hz
• Criticality
• Used to measure the acceleration and the spacecraft’s
respective position
Bosch LRR3: 3rd generation LongRange Radar Sensor
Bosch LRR3: 3rd generation LongRange Radar Sensor
• Detect objects and measure velocity and position relative
to movement of host radar-equipped vehicle
• Distance accuracy 0.5…250m (±0.1m)
• Relative speed accuracy -75…+60m/s (±0.12m/s)
• Vision Range
• Horizontal opening angle 30° (-6 dB)
• Vertical opening angle 5° (-6dB)
• Power Consumption
• Typically 4 W
• Temperature Range
• -40°C to 85°C (periphery)
• Max Number of detected Objects = 32
Bosch LRR3: 3rd generation LongRange Radar Sensor
• Sampling Rate
• Cycle time is typically 80ms
• Signal Band
• Transmits radar waves in 76-77 GHz
• Criticality
• This is useful for landing on the moon as to detect
the distance from the surface of the moon to the
spacecraft
SENSOPART Visor Vision Sensor
SENSOPART Visor Vision Sensor
•
•
•
•
Allows sight via flashing light at fast times
Uses 8 LEDS for fast measurement
Takes 13s to power up when turned on
Voltage Requirement
• 24V DC
Current Consumption
• About 200 mA
• Temperature Range
• -20°C to 60°C
SENSOPART Visor Vision Sensor
• Sampling Rate
• Cycle time is typically 20ms pattern matching
• Cycle time is typically 30ms contour
• 2ms brightness, contrast, grey level
• Signal Band
• Transmits in 62-73 GHz
• Criticality
• This is useful for landing on the moon as to detect
craters and dangerous landmasses so the
spacecraft can land in the designated location
CT-602 Star Tracker
CT-602 Star Tracker
• Sampling Rate
• Cycle time is typically .3 deg/sec
• Signal Band
• Transmits radar waves in 10 Hz
• Criticality
• The CT-602 features a radiation-hardened
processor and additional memory that combine for
increased environmental tolerance and greater
mission programmability
E2EM
E2EM
• Sampling Range
• Measures 4 mm distances
• Signal Band
• Transmits radar waves in 1 kHz
• Criticality
• Long-distance at up to 30 mm enables secure
mounting with reduced problems due to work piece
collisions
K7L-AT50 / -AT50D
Ultra-miniature Sensor Amplifier
K7L-AT50 / -AT50D
Ultra-miniature Sensor Amplifier
•
•
•
•
•
•
Rated power supply voltage of 10 to 30 DC
Detection time is 10s max
Current is 100 mA at 30VDC max
Power needed is 1W
Temperature range is -10 to 55°C
Resistance
• Range 0 = 0 to 250 kΩ
• Range 1 = 0 to 600 kΩ
• Range 2 = 0 to 5 MΩ
• Range 3 = 0 to 50 MΩ
K7L-AT50 / -AT50D
Ultra-miniature Sensor Amplifier
• Sampling Range
• 800ms max
• Signal Band
• 50/60 Hz for 1 min
• Criticality
• Prevents leakage of fuel tanks which would help
prevent potential disasters from happening
KM50-E
Power Monitor
KM50-E
Power Monitor
•
•
•
•
•
Rated power supply voltage of 100 to 240 VAC
Detection time is 10s max
Current is 5,50,100,200,400, or 600 A
Power needed is 4kW to 480 kW
Temperature range is -10 to 55°C
• Accuracy for the time is about ±1.5 min/month at 23°C
KM50-E
Power Monitor
• Sampling Range
• 800ms max
• Signal Band
• 50/60 Hz
• Criticality
• Tells if any electronics systems are damaged or
broken.
HD25A Magnetic Encoder
HD25A Magnetic Encoder
• Sample Rate
• 4 msec
• Signal Band
• 20 kHz max
• Critically
• Using the HD25A magnetic encoder because it
calculates absolute position and also digital to
avoid less errors and noise
Sensors and Signal Bands
Sensor
Frequency Range
Band
DS18B20 Programmable Resolution 1-Wire Digital
Thermometer
1.3 GHz
L band
MPL115A Digital barometric pressure sensor
8 MHz
A band
TR250Z Oxygen Sensor
13.8 GHz to 14.7
GHz
Ku
band
DYNAMENT CARBON DIOXIDE INFRARED SENSOR
15 MHZ
A band
MLX90316 Rotary Position Sensor IC
7 MHz - 20 MHz
A band
Bosch Sensortec BMA180 Digital triaxial acceleration
sensor
7.5 MHz - 10 MHz
A band
Bosch LRR3: 3rd generation Long-Range Radar Sensor
76 GHz - 77 GHz
W band
SENSOPART Visor Vision Sensor
62 - 73 GHz
E band
Magnetic Absolute Encoder
20 kHz
A band
Sensor Block Diagram
Power
Power
LRR3
Range
DS18B20
Temperature
MLX90316
Rotary Position
Sensopart
Landing
MPL115A
Pressure
KM50-E
Power Monitoring
CT-602
Star Tracking
TR250Z
Oxygen
BMA180
Triax Accelerometer
Data
E2EM
Proximity
Dynament
CO2
K7L-AT50
Fuel Leakage
Computer
HD25A
Magnetic Encoder
InsideOutside
Pressure Hull
Sensor Power Requirements
Sensor
Used for
Voltage Requirements
Current Consumption Power Requirement Inside/Outside Craft
DS18B20
Temperature
3-5.5v DC
1-1.5mA
.00825 W
Inside
MPL115A
Pressure
2.4-5.5v DC
5μA
2.75E-5 W
Inside
TR250Z
Oxygen
24v DC
600mA
14.4 W
Inside
Dynament
CO2
3-5v DC
60 mA
.3 W
Inside
MLX90316
Rotary Position
4.5-5.5v DC
8.5-16 mA
.088 W
Inside
BMA180
Triax Accelerometer
4.25v DC
975 μA
.004 W
Inside
LRR3
Range
4W
Outside
Sensopart
Landing
24v DC
4.8 W
Outside
CT-602
Star Tracking
28v DC
9W
Outside
E2EM
Proximity Sensor
24v DC
100 mA
2.4 W
Outside
10-30v DC
100mA
.3 W
Outside
7W
Inside
.088 W
Outside
K7L-AT50 / AT50D
Fuel Leakage
KM50-E
Power Monitoring
HD25A
Magnetic Encoder
Total
5.5v DC
200 mA
16 mA
42.39 W
Criticality
Mission
Crew
Acceleration
Velocity
Position Sensors
Oxygen Levels
CO2 Levels
TR250Z Oxygen Sensor
Dynament CO2 Infrared Sensor
Pressure Levels
Temperature Levels
MPL115A Digital barometric
pressure sensor
DS18B20 Programmable Digital
Thermometer
This Criticality diagram shows how the crew must come first before
the mission because there needs to be a crew to do the mission
Sensor Redundancy
• In order to provide a safe environment for
the crew and keep the mission going, we
need multiple sensors so if one fails, we
have a backup
• We must calculate the probability that at
least one sensor will work in case one or
more fail in it’s place
Sensor Redundancy
Probability that k out or n units working
Sensor Redundancy
• For all the sensors, using the worst mean time
between failures out of all the sensors as a
worst case scenario
Re
Re

t
MTBF
(13 days )*( 24 hours )*( 3600 sec)

5000 hours *3600 sec
R  0.9395
Sensor Redundancy
3 parallel sensors, each has reliability of 0.9395
Probability all three work
P  82.93%
Probability exactly two work
P  16.02 %
Probability exactly one works
P  1.03 %
Sensor Redundancy
Probability all three work
P  82.93%
Probability at least two work
P = 98.95%
Probability at least one works
P = 99.98%
Probability that none work
P(0) = 0.022%
Possible ENAE 484 DBTE
Projects
Sight View Mock-Up
• Want to mock-up the capsule view point to
assure the astronauts have significant
sight lines for landing from the window.
• From mock-up, analyze structure for
possible window placement and quantity
of windows
• Can shine light through windows in the
dark to visualize sight lines easier
Sight View Mock-Up
Inner Configuration Mock-up
• Want to design a mock-up of how the inner structure of the crew
systems vehicle is laid out
• We will design moveable furniture, such as the chairs, control
panels, cubbies, etc. to see if the space suited crew can operate the
controls in a well timed manner
• From this, we will put people in space suits and see if the
configuration we designed for the crew systems vehicle is
satisfactory
– It is satisfactory if the crew can operate all the controls, (within arm’s
length while sitting) and move without much trouble
• If it is deemed unsatisfactory, then the furniture and control systems
is moved into a new configuration until a good configuration is found
• Goal: To see if the crew can react to situations without much trouble
and to become familiar with the crew systems vehicle before the
mission starts
Mock-up: Lunar Egress
Hatch Design
• Objective
• Determine desirable hatch sizes and shapes for egress in
spacesuits after cabin decompression
• Analyze ease of exiting/entering through the hatch, ease of
opening/closing the hatch
• Analyze performance in zero gravity, lunar gravity
• Lunar gravity – further step-down to surface simulation
• Required mockup
• Can create a low cost/ low fidelity dry mockup
• Can create a higher fidelity neutral buoyancy mockup
• Both would require structural construction
• Dry mockup needs more structural support
• NB mockup needs more specialized construction
References
•
•
•
•
•
•
Hatcher, Norman M. A Survey Of Attitude Sensors for Spacecraft. Rep. no. NASA
SP-145. Washington, D.C.: Langley Research Center, 1967. Web. 9 Dec. 2012.
MPL115A Digital Barometric Pressure Sensor. Rep. no. MPL115AFS. N.p.: n.p., n.d.
Freescale Semiconductor. Web. 8 Dec. 2012.
http://cache.freescale.com/file/sensors/doc/fact_sheet/MPL115AFS.pdf
http://cache.freescale.com/files/sensors/doc/data_sheet/MPL115A1.pdf?fpsp=1
http://cache.freescale.com/files/sensors/doc/data_sheet/MPL115A2.pdf?fpsp=1
DS18B20 Programmable Resolution 1-Wire Digital Thermometer. Rep. San Jose,
CA: Maxim Integrated, 2008. Maxim Integrated. Web. 11 Dec. 2012.
http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf
MLX90316 Rotary Position Sensor IC. Rep. no. 3901090316. N.p.: Melexis Micro
Electronic Integrated Systems, 2012. Melexis Micro Electronic Integrated Systems.
Web. 11 Dec. 2012.
http://www.melexis.com/Assets/MLX90316-DataSheet-4834.aspx
BMA180 Digital, Triaxial Acceleration Sensor. Rep. no. Rev. 2.5. N.p.: Bosch, 2010.
Bosch. Web. 10 Dec. 2012.
http://irtfweb.ifa.hawaii.edu/~tcs3/jumpman/jumppc/1107-BMA180/BMA180DataSheet-v2.5.pdf
References
•
•
•
•
•
Chassis Systems Control LRR3: 3rd Generation Long-Range Radar Sensor. Rep.
N.p.: Bosch, 2009. Bosch. Web. 10 Dec. 2012.
http://www.boschautomotivetechnology.com/media/db_application/downloads/pdf/safety_1/en_4/lrr3_d
atenblatt_de_2009.pdf
VISOR- the New Generation of Vision Sensors. Rep. no. 068-14397. N.p.:
SensoPart, 2012. SensoPart. Web. 11 Dec. 2012.
http://www.sensopart.com/jdownloads/Prospekte/06814397_14_VISOR_e.pdf
http://www.sensopart.com/en/products/vision-sensors-a-systems/obect-detection
HD25A Absolute Industrial Optical Encoder. Rep. N.p.: US Digital, n.d. US Digital. US
Digital. Web. 11 Dec. 2012.
http://pdf.directindustry.com/pdf/us-digital/hd25a-absolute-industrial-opticalencoder/Show/15092-187916.html
TR250Z Oxygen Sensor. Rep. no. DSTR250Z. N.p.: CO2Meter,
2012. CO2Meter.com. CO2Meter. Web. 12 Dec. 2012.
http://www.co2meters.com/Documentation/Datasheets/DS-TR250Z-sensor.pdf
Carbon Dioxide Infrared Sensor Temperature Compensated Certified Version Type
MSh-CO2/TC. Rep. no. TDS0003. Vol. 4.3. N.p.: Dynament, 2011. Dynament. Web.
11 Dec. 2012.
http://www.dynament.com/infrared-sensor-data/tds0003.PDF