Transcript Pratham, IITB Student Satellite

Pratham, IITB Student Satellite
Saptarshi Bandyopadhyay
System Engineer, Pratham
IIT Bombay
27th August, 2008
"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. "
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!
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 (< 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
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MINI – SPUTNIK
ASUSAT
NCUBE
SSETI
AAU Cubesat
SNOE
ICARUS
CATSAT
DTUSAT
MEROPE
COMPASS
SEEDS
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 need success in our first
 We should launch at least 5 satellites within
Mission!!
the next 20 years.
 The Satellites could be test-beds for new
technology that is being developed in the
institute and need space qualification.
The IITB Student Satellite Team for Pratham
Sub-System
Number of
Payload
Students
Number
of Students
Department
4
Aerospace6
5
Engineering
Third Year
Communication
1
Attitude
Determination
4 and
Controls
On Board13
Computer
Second Year
Power
Year
Fifth year
Fourth Year
Number of
Students
9
4
Physics
15
Structures and
Thermals
Electrical7
5
Computer Science
5
Mechanical
System Engineer
Civil
1
Chemical
11
3
2
1
3
List of Professors
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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)
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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)
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.
Timeline for Pratham till now
Period
August 07
Sept – Oct 07
Dec 07
Description
Concept feasibility proved to the Aerospace
Department
IITB Satellite Team was selected
First trial at modeling satellite subsystems
Jan – Apr 08
Detailed study of all subsystems with TEC
and Thermopile as Payload for the satellite.
Requirements capture report was written.
May 08 – July TEC has been finalized as the only Payload.
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Conceptual Design Phase finished.
August 08 –
Present
Preliminary Design Phase. Engineering
Model will be built.
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)
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 (?)
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.
Communication and Ground Station
 Low bit rate Beacon. (Freq = 437MHz)
 High bit rate (1.2kbps) Monopole for
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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
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
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
Power Systems
Hardware
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Solar cells
Batteries
3.3V regulator
5V regulator
Microcontroller
Power distribution
Battery protection
Power OR-ing diodes
RBF pin, kill and
charging switches
A
A’
B
21W 7W
B’
C
C’
17W 17W 20W 2W
 Major power inputs
 Direct solar radiation
 Solar radiation reflected
from Earth (albedo)
 Earth’s thermal radiation
 Average useful power
incident on the faces.
 PDR
Tot
84W
Structures, Thermals and Mechanisms
Structures
 Weight budgeting
 Qualification of the
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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
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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
System Engineer’s Tasks
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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
Future Plan
Period
Present – Sept
Sept – Dec 08
Jan – Feb 09
Description
Preliminary Design Phase
(Engineering Model)
Detailed Design Phase
(Qualification Model)
Prototype Testing and Qualification Phase
Mar – April 09 Flight Testing phase
(Flight Model)
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
Inducting new Students
 Quiz (24th September)
 Student Satellites
 Our Reports
 Sub-System specific
For registering mail:
[email protected]
 Presentation (October)
 Members become formal in
Dec 08
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System Engineering
Payload
Communication
Controls
On Board Computer
Power
Structures
Thermal
Mechanisms