Pratham, IITB Student Satellite

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Pratham, IITB Student Satellite
Saptarshi Bandyopadhyay System Engineer,
Pratham IIT Bombay 27th August, 2008
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"There are some who question the relevance of
space activities in a developing nation. To us,
there is no ambiguity of purpose. We do not have
the fantasy of competing with the economically
advanced nations in the exploration of the moon
or the planets or manned space-flight. But we are
convinced that if we are to play a meaningful
role nationally, and in the community of nations,
we must be second to none in the application of
advanced technologies to the real problems of man
and society. "
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Indian Space Research Organization

• Over 40 years of experience in space.
• 31 Indian satellites successfully launched.
• Indigenous profitable launch vehicles.
• We are going to the Moon!

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Student satellite The Idea!

• The aim is to develop a satellite which can be
  made within a time frame of two or three years,
  be of low cost, low mass (lt 10kgs) and launch it
  into orbit.
• Use of COTS instruments to reduce costs.
• Success of the mission attached to process of
  learning and not just the final output.
• The first Cubesat was used as an technology
  evaluation mission AAU Cubesat mission
  statement

• MINI SPUTNIK
• ASUSAT
• NCUBE
• SSETI
• AAU Cubesat
• SNOE
• ICARUS
• CATSAT
• DTUSAT
• MEROPE
• COMPASS
• SEEDS

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COMPASS-I Aachen University of Applied
Sciences, Germany
ASUSAT University Of Arizona Arizona, USA
MEROPE Montana StateUniversity Montana, USA
NCUBE University Of OSLO, Norway
Its OUR Turn Now !!!
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Grand Plan for the Student Satellite Project at
IIT Bombay!

• We wish to make IIT Bombay a respected center for
  advancement in Satellite Technology, in the
  world.
• We should launch at least 5 satellites within the
  next 20 years.
• The Satellites could be test-beds for new
  technology that is being developed in the
  institute and need space qualification.

We need success in our first Mission!!
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The IITB Student Satellite Team for Pratham
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List of Professors

• Prof K. Sudhakar (Aero)
• Prof H. Arya (Aero)
• Prof P. M. Mujumdar (Aero)
• Prof S. P.Bhat (Aero)
• Prof K. Chatterjee (Elec)
• Prof B. G. Fernandes (Elec)
• Prof K. N. Iyer (Mech)
• Prof R. K.Pant (Aero)
• Prof K. K.Isaac (Mech)
• Prof U.N.Gaitonde (Mech)

• Prof R.K.Shevgaonkar (Elec)
• Prof R. N. Banavar (Elec)
• Prof Madhu N. Belur (Elec)
• Prof V. Ramgopal Rao (Elec)
• Prof D.K.Sharma (Elec)
• Prof Krithi Ramamritham (CS)
• Prof Subhananda Chakrabarti (Elec)

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Mission Statement for Pratham

• Acquiring knowledge in the field of Satellite and
  Space Technology.
• Develop the Satellite through the phases of
  Design, Analysis, Fabrication and Testing.
• Launch the satellite, Measure TEC of the
  Ionosphere and create TEC map of India.
• Involve students from other universities in our
  Satellite project.

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Timeline for Pratham till now
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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 other ISRO scientist.
• All our documents are available on our website
• For Password Contact any of the people mentioned
  in the Contacts List (On website)

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Payload

• Total Electron Count of the Ionosphere
• Method used for measuring TEC on our Satellite
• Faraday rotation
• linearly polarized radio waves at 405MHz and
  437MHz
• Difference in polarization measured on ground
  using crossed yagi.
• TEC maps of India
• Ionosphere Tomography (?)

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Social Goal

• The greater the number of ground stations,
  greater is the number of locations at which TEC
  will be recorded.
• We plan to approach universities across India
  requesting them to serve as a ground station for
  our satellite.
• This will motivate the participating students and
  get them interested in satellite technology.

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Communication and Ground Station

• Low bit rate Beacon. (Freq 437MHz)
• High bit rate (1.2kbps) Monopole for downlink of
  data. (Freq 405MHz)
• We do not have uplink
• Linearly polarized radio signals.
• 2 crossed yagis at ground stations to receive
  data and measure their polarization.
• PDR
• Simulation of onboard Monopoles and circuit
• Ground Stations for IITB, Tomography and Social
  Goal

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Attitude Determination and Controls

• Goal
• To stabilize the satellite after deployment and
  to maintain the 3 axis attitude of the satellite
  within
• Functional Requirements
• Detumbling Mode
• Nominal Operation Mode
• Emergency Mode
• Control law
• Linear controller

• Sensors
• GPS (1)
• Single Rate gyro (3)
• Single axis sun sensor (6)
• Magnetometer (1)
• Actuators
• Magnetorquer (3)
• PDR
• Hardware
• Software

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On Board Computer

• Hardware
• Microcontroller
• Atmel AT91M40080
• PROM
• One time programmable EPROM AT27BV040
• NVRAM
• TI bq4015LYMA-70N

• Software
• Stages of Operation
• Minimal pre-empting of running task
• Cyclic Scheduler
• PDR
• Hardware
• Software

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Power Systems

• Hardware
• Solar cells
• Batteries
• 3.3V regulator
• 5V regulator
• Microcontroller
• Power distribution
• Battery protection
• Power OR-ing diodes
• RBF pin, kill and charging switches

• Major power inputs
• Direct solar radiation
• Solar radiation reflected from Earth (albedo)
• Earths thermal radiation
• Average useful power incident on the faces.

• PDR

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Structures, Thermals and Mechanisms

• Structures
• Weight budgeting
• Qualification of the satellite structure as per
  launch loads
• Qualification of structure based on thermal loads
  in orbit
• Configuration Layout
• Deployment of 2 parallel monopoles
• PDR Structure
• PDR Mechanisms

• Thermal
• Maintain suitable temperature for components.
• Temporal cycle of temperatures experienced in
  each orbit
• Spatial gradient of temperature at an instant
• Dissipation of heat from components onboard
• Active thermal control of critical components
• PDR - Thermals

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System Engineers Tasks

• Stages and Functions of Satellite
• System and Sub-System Requirements
• Budget for Weight, Power and Data
• Interface, Connectors and Wires
• Configuration Layout
• Launch Vehicle Interface and Access Ports
• PDR

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Future Plan
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New Satellite

• Thermal Imaging using the sensors developed by
  Prof Subhananda Chakrabarti (Elec).
• Use of Mems sensors
• Launch Vehicle Interface
• Try uplink! . . .
• Team starts work by December 2008
• Satellite should be launched by 1st quarter 2010

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Inducting new Students

• Quiz (24th September)
• Student Satellites
• Our Reports
• Sub-System specific
• For registering mail shashanktamaskar_at_iitb.ac.in
  
• Presentation (October)
• Members become formal in Dec 08

• System Engineering
• Payload
• Communication
• Controls
• On Board Computer
• Power
• Structures
• Thermal
• Mechanisms

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Thank You