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

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

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/

Organizations Supporting Pratham

ISROISACVSSC

IIT BombayIRCCCDEEPAEA

SAMEERTIFRBoeing

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,

Thank You