1. Pratham IITB Student Satellite
Saptarshi Bandyopadhyay
Project Manager and System Engineer
Pratham, IIT Bombay
12th March, 2010

2. 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
MINI – SPUTNIK
ASUSAT
NCUBE
SSETI
AAU Cubesat
SNOE
ICARUS
CATSAT
DTUSAT
MEROPE
COMPASS
SEEDS

3. 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

4. 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.

5. 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%

6. 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

7. PRATHAM Team Size: 38 Departments: Aero Chem Civil CS Elec EP Mech
Integration Team
Quality Team
Core Group
(10 members)
PR Team
Structure
OBC
Power
Comm
Thermal
Payload
Control
Mechanism

8. 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)

9. Timeline Period Description Aug 07
Concept feasibility proved to the Aerospace Department
Sep 07 – Apr 08
Requirements Capture Phase finished. TEC chosen as Payload.
May 08 – Jul 08
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

10. Payload Social Goal 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

11. TEC Coverage over the World

12. 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

13. 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

14. 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

15. Power Subsystem Hardware Major power inputs
Direct solar radiation
Solar radiation reflected from Earth (albedo)
Earth’s thermal radiation
Average useful power incident on the faces
Hardware
Solar cells
Batteries
3.3V regulator
5V regulator
Microcontroller
Power distribution
Battery protection
Software ready A A’ B B’ C C’
Tot
21W 7W
17W
20W 2W
84W

16. Level 2 testing for Power, OBC, Controls, and Communication
OILS (HILS)
Level 2 testing for Power, OBC, Controls, and Communication
Hardware ready
Working on Real-time Software

17. Static Analysis: Displacement
Structure Subsystem
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
Static Analysis: Displacement
Modal analysis: 1st mode

18. 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

19. 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

20. 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

21. 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)

22. 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

23. Organizations Supporting Pratham
ISRO
ISAC
VSSC
IIT Bombay
IRCC
CDEEP
AEA
SAMEER
TIFR
Boeing

24. 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.

25. 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

26. Quiz (Wed, 24th March, 2010) Electrical Mechanical
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
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,

27. Thank You