Post on 25-Feb-2016
description
PrathamIITB Student Satellite
Saptarshi BandyopadhyayProject Manager and System
EngineerPratham, IIT Bombay
12th March, 2010
Student satellite – The Idea!Aim - To develop a satellite in
a time frame of 2-3 yearsbe of low costlow mass (< 10kgs)launch it into orbit
COTS instruments to reduce costs Success of mission attached to process of learning, not just final output
1. MINI – SPUTNIK
2. ASUSAT3. NCUBE4. SSETI5. AAU Cubesat6. SNOE7. ICARUS8. CATSAT9. DTUSAT10.MEROPE11.COMPASS12.SEEDS
Grand Plan forIIT Bombay Student Satellite
ProjectMake 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 knowledgein Satellite and Space Technology.Have the Satellite entirely designedby the student body of IIT Bombay. Have the Satellite launched; measure TEC of the Ionosphere above IITB.Involve students from other universitiesin our Satellite project.
Success Criteria
DescriptionMission 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 PrathamWeight ~ 10 kgsSize 260mm X 260mm X 260mmLVI from VSSCSolar panels on 4 sidesOrbit 10:30 polarsun-synchronous, 817km altitude 3 pre-deployed monopolesDownlink at 2 frequencies(145MHz and 437MHz)No tele-command, fully autonomous4 months mission life
Comm
Payload Control
Structure
PRATHAM Integration Team
PR Team
Quality TeamCore Group
(10 members)
PowerOBC
Mechanism
Thermal
Team Size: 38 Departments:AeroChemCivilCSElecEPMech
Technical MentorsProf 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)
TimelinePeriod 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
PayloadTotal Electron Count - IonosphereTEC map above Ground StationIonosphere Tomography Method used - Faraday rotation
Social Goal Ground station workshops
11 participating universities
MHRD Virtual ExperimentsCollaboration with IPGP, France
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
GoalStabilize the satellite after deployment
Maintain 3 axis attitude stabilization of the satellite
SensorsGPS (1)
Single axis sun sensor (6)
Magnetometer (1)
ActuatorsMagnetorquer (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
HardwareTwo ATMega 128 micro-controllers
One Interfaces with Power, Sensors and Actuators (master)Other dedicated to CC1020 (slave)
Hardware BussesSPII2CUART
External EEPROM
Final Hardware designs ready
Software
Minimal pre-empting of running task
Cyclic Scheduler
Software almost ready
Power Subsystem
HardwareSolar cellsBatteries3.3V regulator5V regulatorMicrocontrollerPower distributionBattery protection
Software ready
Major power inputs
Direct solar radiation Solar radiation reflected from Earth (albedo) Earth’s thermal radiation
Average useful power incident on the faces
A A’ B B’ C C’ Tot21W
7W 17W
17W
20W
2W 84W
Level 2 testing for Power, OBC, Controls, and Communication
OILS (HILS)
Hardware readyWorking on Real-time Software
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
Modal analysis: 1st mode
Static Analysis: Displacement
Thermals SubsystemMaintain 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 SequenceSystem and Sub-System RequirementsBudget for Weight, Power and DataInterface, Connectors and WiresRouting of WiresConfiguration Layout (External / Internal)LVI from ISRO and Access PortsConnectivity DiagramIntegration SequenceLevel 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 ReviewsMajor 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/
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, BangaloreConformal Coating of circuitsThermovac Test – TIFR, MumbaiVibration Test – TIFR Hyderabad, ISAC BangaloreOther Tests – SAC Ahmedabad, ISAC BangaloreIntegration with LV – VSSC, Trivandrum Launch of the Satellite – SHAR, Shriharikota
Quiz (Wed, 24th March, 2010)
ElectricalNeed 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 PrathamSub-Systems: Payload, Comm, Controls, OBC, Power, OILS, Quality
MechanicalNeed 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,