Transcript Pratham, IITB Student Satellite Conceptual Design Review

Saptarshi Bandyopadhyay
Project Manager and System Engineer
Pratham, IIT Bombay
12th March, 2010
Student satellite – The Idea!
Aim - To develop a satellite in
a time frame of 2-3 years
be of low cost
low mass (< 10kgs)
launch it into orbit
COTS instruments to reduce
costs
Success of mission attached to
process of learning, not just
final output
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MINI – SPUTNIK
ASUSAT
NCUBE
SSETI
AAU Cubesat
SNOE
ICARUS
CATSAT
DTUSAT
MEROPE
COMPASS
SEEDS
Grand Plan for
IIT Bombay Student Satellite Project
Make
IIT
Bombay
a
respected
center
for
advancement in Satellite and Space Technology in
the world
Launch at least 5 satellites within the next few years
Satellites as test-beds for new technology that is
being developed in the institute and need space
qualification
Mission Statement for Pratham
Acquiring knowledge
in Satellite and Space Technology.
Have the Satellite entirely designed
by the student body of IIT Bombay.
Have the Satellite launched; measure TEC
of the Ionosphere above IITB.
Involve students from other universities
in our Satellite project.
Success Criteria
Description
Mission
Success
Flight Model ready
50%
Beacon Signal received
60%
Communication link established
70%
TEC measurements at IITB
80%
Satellite functional for 4 months
100%
Vital Statistics of Pratham
Weight ~ 10 kgs
Size 260mm X 260mm X 260mm
LVI from VSSC
Solar panels on 4 sides
Orbit 10:30 polar
sun-synchronous, 817km altitude
3 pre-deployed monopoles
Downlink at 2 frequencies
(145MHz and 437MHz)
No tele-command, fully autonomous
4 months mission life
Team Size: 38
Departments:
Aero
Chem
Civil
CS
Elec
EP
Mech
PRATHAM
Integration Team
Quality Team
Core Group
(10 members)
PR Team
OBC
Power
Structure
Comm
Thermal
Payload
Control
Mechanism
Technical Mentors
Prof K. Sudhakar (Aero)
Prof P. M. Mujumdar (Aero)
Prof H. Arya (Aero)
Prof H. B. Hablani (Aero)
Prof S. P. Bhat (Aero)
Prof K. Chatterjee (Elec)
Prof B. G. Fernandes (Elec)
Prof K. N. Iyer (Mech)
Dr K P Ray (SAMEER)
Prof Madhu N. Belur (Elec)
Prof Krithi Ramamritham
(CS)
Prof R. K. Pant (Aero)
Prof K. K. Isaac (Mech)
Prof U. N. Gaitonde (Mech)
Prof R. K. Shevgaonkar (Elec)
Prof R. N. Banavar (Syscon)
Prof D. K. Sharma (Elec)
Prof R. P. Shimpi (Aero)
Prof Girish Kumar (Elec)
Prof Kavi Arya (CS)
Prof B Bandyopadhyay
(Syscon)
Timeline
Period
Aug 07
Description
May 08 – Jul 08
Concept feasibility proved to the
Aerospace Department
Requirements Capture Phase finished.
TEC chosen as Payload.
Conceptual Design Phase finished.
Aug 08 – Apr 09
Preliminary Design Phase finished.
29th Sept, 09
Signed of the MoU with ISRO!
May 09 – Apr 10
Detailed Design Phase
May 10 – launch
Flight Testing phase
Sep 07 – Apr 08
Payload
Total Electron Count - Ionosphere
TEC map above Ground Station
Ionosphere Tomography
Method used - Faraday rotation
Social Goal
Ground station workshops
11 participating universities
MHRD Virtual Experiments
Collaboration with IPGP,
France
TEC Coverage over the World
Communication and
Ground Station
Low bit rate Beacon (145MHz)
High bit rate (1.2kbps) Monopole for
downlink of data (437MHz)
NO telecommand
Linearly polarized radio signals
2 crossed yagis at ground stations to receive
data and measure their polarization
Low cost ground stations for
other
universities
(approx INR 25000/-)
Kill Switch (Uplink) added to satisfy
IARU’s constraint for getting license
Attitude Determination and Control
Goal
Stabilize the satellite after
deployment
Maintain 3 axis attitude
stabilization of the satellite
Sensors
GPS (1)
Single axis sun sensor (6)
Magnetometer (1)
Actuators
Magnetorquer (3)
Control law
Linear controller
Kalman Filter for sensor fusion
Stability Analysis
Robustness Analysis
Manufacturing accuracies
needed
Estimator and Controller
fully functional
Monte Carlo simulations
running
On Board Computer Subsystem
Hardware
Two ATMega 128 micro-controllers
One Interfaces with Power, Sensors
and Actuators (master)
Other dedicated to CC1020 (slave)
Hardware Busses
SPI
I2C
UART
External EEPROM
Final Hardware designs ready
Software
Minimal pre-empting of
running task
Cyclic Scheduler
Software almost ready
Major power inputs
Power Subsystem
Direct solar radiation
Solar radiation reflected from
Earth (albedo)
Earth’s thermal radiation
Hardware
Solar cells
Batteries
3.3V regulator
5V regulator
Microcontroller
Power distribution
Battery protection
Software ready
Average useful power
incident on the faces
A
A’
B
B’
C
C’
21W
7W
17W
17W
20W 2W
Tot
84W
OILS (HILS)
Level 2 testing for Power, OBC, Controls, and Communication
Hardware ready
Working on Real-time
Software
Structure Subsystem
Static Analysis: Displacement
Qualification of the satellite
structure as per launch loads
Qualification of structure
based on thermal loads in
orbit
Software – ANSYS
Analysis of final model has
started
Modal analysis: 1st mode
Thermals Subsystem
Maintain suitable temperature for components.
Temporal cycle of temperatures experienced in orbit
Spatial gradient of temperature at an instant
Dissipation of heat from components onboard
Active thermal control of critical components
Fluent to Nastran to our own C++ codes to ISAC’s Ideas
Going to ISAC for final Thermal design
Mechanisms Subsystem
Deployment of 2 parallel
monopoles (ditched!)
IBL – 230 V2, Micro
Satellite Separation System
SNAP Mechanism –
Separation from LVI
To be given by VSSC
System Engineering and Integration
Stages and Functions of Satellite; Operational Sequence
System and Sub-System Requirements
Budget for Weight, Power and Data
Interface, Connectors and Wires
Routing of Wires
Configuration Layout (External / Internal)
LVI from ISRO and Access Ports
Connectivity Diagram
Integration Sequence
Level 2 and Level 3 Testing
Quality Assurance
“ QA refers to planned and systematic production
processes that provide confidence in a product's suitability
for its intended purpose ”
Electrical QA
Mechanical QA (~1)
Software QA
Clean Room being built (100,000 class)
Documentation and Reviews
Major emphasis on documentation
“ We want to preserve our knowledge ”
Regular review done by the team and faculty
Reports written and circulated within the team
Reviews done in ISAC and by other ISRO scientists
All our documents are available on our website
www.aero.iitb.ac.in/pratham/
Organizations Supporting Pratham
ISRO
ISAC
VSSC
IIT Bombay
IRCC
CDEEP
AEA
SAMEER
TIFR
Boeing
Why we need you!
Number of students in
the team during
summer will drop, due
to summer interns.
Most of these students
have already been with us
for over 2.5 years
Hence strong technical
skills in electrical and
mechanical subsytems
required.
Students will be trained
after they join the team.
Grading of freshies,
sohpies and mtech will be
done separately
All students need to pass
through quiz followed by
presentation for entering
the team.
What you will do?
Design should be over by then. But you should
have capability to understand design and suggest
changes if faults are found.
Testing of the Qualification and Flight Model
Fabrication of Flight Hardware – ISAC, Bangalore
Conformal Coating of circuits
Thermovac Test – TIFR, Mumbai
Vibration Test – TIFR Hyderabad, ISAC Bangalore
Other Tests – SAC Ahmedabad, ISAC Bangalore
Integration with LV – VSSC, Trivandrum
Launch of the Satellite – SHAR, Shriharikota
Quiz (Wed, 24th March, 2010)
Electrical
Need good knowledge of
circuit design, electronics
and communication fundae,
controls, quality etc.
Electrical components on
Pratham like GPS,
Magnetometer, SS, etc.
Knowledge about 6 electrical
boards onboard Pratham
Sub-Systems: Payload,
Comm, Controls, OBC,
Power, OILS, Quality
Mechanical
Need good knowledge of
structures, thermals,
mechanisms, etc.
Read up on integration, wire
routing, system engineering,
budgeting of weights, etc.
Knowledge about
mechanical structure of
Pratham
Sub-Systems: Mechanism,
Structures, Thermals, System
Engineering, Integration,