Saptarshi Bandyopadhyay Project Manager and System Engineer Pratham

Saptarshi Bandyopadhyay Project Manager and System Engineer Pratham, IIT Bombay 12 th 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 (< 10 kgs) launch it into orbit COTS instruments to reduce costs Success of mission attached to process of learning, not just final output 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 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 260 mm X 260 mm LVI from VSSC Solar panels on 4 sides Orbit 10: 30 polar sun-synchronous, 817 km altitude 3 pre-deployed monopoles Downlink at 2 frequencies (145 MHz and 437 MHz) 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 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. 29 th Sept, 09 Signed of the Mo. U with ISRO! May 09 – Apr 10 Detailed Design Phase May 10 – launch Flight Testing phase

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 (145 MHz) High bit rate (1. 2 kbps) Monopole for downlink of data (437 MHz) 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 CC 1020 (slave) Hardware Busses SPI I 2 C 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. 3 V regulator 5 V regulator Microcontroller Power distribution Battery protection Software ready Average useful power incident on the faces A A’ B B’ C C’ 21 W 7 W 17 W 20 W 2 W Tot 84 W

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: 1 st 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 V 2, 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, 24 th 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,

Thank You