Transcript leonidas - University of Hawaii - Department of Electrical Engineering

By Matthew
Patterson
Low
Earth
Orbit
Nanosatellite
Integrated
Distributed
Alert
System
Why focus on Nanosats?
–The cost and time to design, develop and
complete an entire mission for typical large
satellites is enormous.
–Microsatellites and Nanosatellites allow
quicker mission overturn.
–Risk for missions are reduced
–Provide a means to test new scientific
technologies
–Because we have the ability to complete an
entire mission from concept design to launch
The LEONIDAS Team
•Project Director-Dr. Luke Flynn
•Principal Investigator- Lloyd French
Aukai Kent – Payloads
Jennie Castillo – Orbits
Dennis Dugay - Communications
Kaipo Kent – Thermal
Matt Patterson - Power
Lynette Shiroma - Attitude & Control
Zachary Lee-Ho - Systems Engineer
Minh Evans – Command & Data
Handling
Mike Menendez - Structure and
Mechanical Devices
What have we
accomplished?
•Learned the basic concepts in mission design
and development
•Developed a mission concept report for the
LEONIDAS BUS
•Prepared proposal for Air Force Office of
Scientific Research University Nanosatellite
Competition
•Presented our mission design to Jet
Propulsion Laboratory and Ames
Mission Objectives
– We will send a microsatellite into a LEO,
sun-synchronous, polar orbit
– The microsatellite will serve as a platform
for demonstrating scientific technologies
– Data attained through the operations of the
scientific technology payloads will be
transmitted to the ground station
– The development, manufacturing and
launching of the satellite will serve as an
educational tool for aiding the development
of students at the University of Hawaii at
Manoa
Plug and Play Bus
Mission Requirements
• Satellite must accurately point and orient itself to take a
picture of Hawaii
• Satellite shall be robust and reliable
– This will be accomplished through:
• Minimizing the use of mechanical devices
• The use of COTS components and interfaces
• Operation of payloads or communication with ground station
will be accomplished within the 14 minute viewing window of
each orbit.
• Cost of components must not exceed ~ $500k
– Cost estimation does not reflect the cost for structure and
sublimation thrusters
• All scientific demonstrations will be performed within the
projected mission lifetime of six months
• The shall be sufficient amount of battery power to operate the
satellite for a duration of 12 hours, in the event the
photovoltaics should fail.
Power
Regulation
and
Distribution
Power Management and
Distribution
•
Objective:
– To provide, store, distribute, and control the satellites power at
Beginning of Life (BOL) and End of Life (EOL).
•
Key Requirements:
– To provide a continuous source of power to loads and subsystems
through out the mission life (6 months – 1 year).
– Support and distribute different voltages (3, 5, +-12, 28V) to variety of
loads.
– Provide enough power to support peak electrical load and provide
enough power at total loss of solar cells for 12 hrs.
– Protect against failures in the System.
– Fit volume and weight budget: 20x27x11[cm3], 4.1 kg
Space
Shunts
PV
Batteries
TT&C
Sun
Thermal
PV
PRU
PDU
ACS
Earth
Payloads
C&DH
Batteries
PV
Shunts
Space
PV: Ultra Triple Junction Cells
GaInP/GaAs/Ge
(Gallium Indium diphosphate/Gallium Arsenide/Germanium)
•
Bare Cells
– Weight = 76.608 mg
– Dimensions = .5 x .22 (m)
– Thickness = ~ 0.140 mm
•
Operating Temperature range = (0˚C – 75 ˚C)
– For every degree off, degrades by .5%
•
UTJ
–
–
–
•
BOL
– Power @28.3%x1,367 W/m2(average solar illumination intensity) = 386.86 W/m2
– Power of Sat : 386 W/m2 x .114 m2 = 44 W per panel
– Peak Power output of solar panels (ideal 3 panels) = 106.225 W
EOL (5 year lifetime)
– Power @24.3% = 332.181 W/m2
– Power of Sat = 37.9 W per panel
– Peak Power output of solar panels = 91.499 W
•
(Ultra Triple Junction) Solar Cell
BOL average efficiency = 28.3%
EOL average efficiency = 24.3%
Degrades .8% per year
Rechargeable Lithium-ion
Battery
•
Characteristics
– Height = .065 m
– Width = .060 m
– Thickness = .0196 m
– Weight = .153 kg
– Energy = 26 Wh
– Life = 500 cycles
– Charge Temp range = (-20˚C – 75 ˚C)
– Charge rate = 2 to 3 hrs @ 6.8 A
•
# of batteries = ?
– In order to meet last for 12 hrs at total failure of Solar Cells
# of batteries needed to operate = 16
Power Regulation Unit
HESC 104
High Efficiency and Smart Charging Vehicle Power Supply
•
Characteristics
– Length = .09525 m
– Width = .09017 m
– Height = .01524 m
– Weight = .186 kg
– Temp range = (-40˚C – 85 ˚C)
– Charge Current = 0 to 4 A
– Charge Voltage = 9.5 to 19.5 V
– Input Voltage = 6 to 40 V
•
Provides for 3, 5, +-12 V
Analysis of Requirements
•
•
Given:
– WBol, avg = 106.225 W
– WEol, avg = 91.499 W
Need:
– Wpeak, bus = 76 W x 30% = 99 W
– Wellipse, bus = 40 W x 30% = 52 W
•
Weight < 4.1 kg
.186 kg
(PRU)
76.608 mg (Bare Cells)
+.153 kg x 10 (batteries)
1.716 kg
+casing for solar cells, extra
batteries, more PRU’s if needed,
wires, resistors)
< 4.1 kg
•
Volume: < 20x27x11 cm
– PRU = 9.5 x 9.0 x 1.5 cm
– Battery = 6.5 x 6.0 x 1.96 cm
Plenty of room because the batteries may be in
their own side compartment.
•
Temperature, to satisfy all = (0˚C – 75 ˚C)
•
Life
– Ideally we can last for 2 yrs. If
everything doesn’t degrade faster than
expected and still needing the same
power.
What’s left?
• Everything!!!!
• Cost
• Integrating
– My parts
– Sats parts
• Case for solar panels meeting mass budget
• Team analysis on subsystems needs
• More calculations!!!
Gantt Chart
Sept
AFOSR
Oct
Nov
Dec
Jan
Feb
Mar
Done
JPL PDR
Team Chart
Done
JPL CDR
POWER
Sept
Find Item
Oct
Nov
Dec
Jan
Waiting
on
companies
Done
My Chart
Cost
Integrating
Research
Feb
Mar
Thank You!!
Till the next time!!!
Happy Thanksgiving Everyone!!!