NANYANG RESEARCH PROGRAMME Design, Build, & Testing of a 3U - - PowerPoint PPT Presentation

NANYANG RESEARCH PROGRAMME

Design, Build, & Testing of a 3U Nanosatellite [EEE01B]

Michael Hoon Yong Hau Jurong Pioneer Junior College Liu Yan Qin Nanyang Junior College

Dimensions of a CubeSat

• Standard 1U CubeSat
• 10 × 10 × 10cm
• Mass of 1.33 kg
• Radiation Hardened Aluminium

Chassis

Reasons for CubeSat Development

• Introductory teaching tool for students to learn about space

hardware

• Reduce cost and development time, which provides increased

access to space hardware for universities

• Ensures that Singapore remains competitive and relevant in the

space industry, especially due to its small size

Subsystems

• Communication with the ground station [COMM]
• On-Board Data Handling and Storage [OBDH]
• Attitude Determination and Control System [ADCS]
• Electrical Power System [EPS]
• Mechanical Structure and Thermal Control System
• Payload

Main Focus of Project

• 1. Electrical Interfacing of the different components in a standard

3U CubeSat

• 2. Determining the most efficient variation of the electrical

interface that would best suit our selected parts

• 3. Create a functional block diagram depicting the numerous

electrical interfaces present

Mission Objective of SCOOBI

• Two spectrometers will measure solar irradiance in the visible and NIR

bands of the E-M spectrum

• Data collected will be used to corroborate data for models proposed

by NASA

• Imager to capture images in LEO
• IoT device
• More payloads will be added in the future

Theory review

• Research on different types of electrical interfaces
• I2C
• SPI
• UART/USART
• CAN
• Determine Advantages/Disadvantages and allocate accordingly

UART

• Universal Asynchronous Receiver Transmitter
• Hardware device for serial communication between computer

subsystems

• Usually part of an Integrated Circuit (IC)
• Advantages
• 2 lines, no clock signal
• Disadvantages
• Only 1 master and slave,
• Baud rates must be similar between devices for UART to work

I²C

• Inter-Integrated Circuit
• Fast communication between master and slave units
• Advantages
• Only 2 wires
• Able to support multiple masters and slaves
• Disadvantages
• More complex wiring and programming
• Slower data transfer rates than SPI but higher than UART

SPI

• Serial Peripheral Interface
• High speed communication interface typically used for short-

distance communication within a system

• Advantages:
• High speed, lower power usage, allows for simultaneous flow of data
• Disadvantages
• Uses 4 wires and more pins
• Only handles short distances

CAN

• Controller Area Network
• An interface designed to allow subsystems to

communicate with each other without the need for complex wiring

• Advantages
• More resistant against EM interference
• Less wiring
• Disadvantages
• More development costs for software development

and maintenance

Literature Review

• Case study on DIP report done by undergraduates
• Proposed a design of a 2U CubeSat, which utilized I²C

protocol between every component

• Programmed using an Arduino UNO microcontroller as the

OBC Key Takeaways: 1. Using I²C as the main communication protocol may be convenient, but does not reap the most efficient results 2. Extensive research must be conducted on the electrical interface for an actual CubeSat, and must not be neglected.

Methodology

• Design and proposal of the electrical interface was based on the

selected parts of the CubeSat

• Parts were selected based on a multitude of factors such as cost

and weight, apart from the communication protocols which they support

• Communication Protocols were allocated to best suit the parts,

such as high baud rate requirements or synchronous communication

On-Board Computer in C&DH

• Based on the ARM Cortex M4

Processor, clock speed of 180MHz

• Highly versatile as multiple

customizable interfaces are available

• 1 CAN Bus interface, 2 USART and 1

UART, 2 SPI, 2 I²C, 1 USB for connections with a PC EnduroSat OBC Module

ADCS Module - Magnetorquer

• The OBC includes integrated ADCS sensors for magnetorquer

control and orientation data collection

• Two 3-axis digital compasses for measuring Earth’s magnetic

fields, accelerometers to measure acceleration

• The main orientation device for SCOOBI is a permanent

magnet which aligns itself with Earth’s magnetic field.

COMM Module – Transceiver + Antenna

• Acts as a two-way radio system
• Able to transmit and receive data to and

from the ground station

• Operates in the UHF band ~430-440MHz
• Transceiver will utilise UART, while Antenna

uses I²C for deployment controls

• Chosen based on native support of

interfaces

EnduroSat UHF Transceiver Antenna Module

Table of Comparison - COMM

EPS Module

• Chosen to reduce compatibility issues with the

OBC

• Supports up to two Li-Po batteries of 10.4Wh

each

• Supports UART, I²C and USB
• The UART interface will be used as synchronous

communication and high baud rates are not required

EnduroSat EPS Module

Table of Comparison - EPS

Payload

• Two spectrometers measuring solar irradiance in

the Near-Infrared and Visible bands of the E-M Spectrum

• Corroborate aviation models proposed by NASA
• Provides real-time tracking of the amount of

radiation received by flight personnel on a flight

• Interface used will be UART and I²C as high baud

rates are required to transfer data

SparkFun Spectrometer Device

Final Functional Block Diagram of SCOOBI

Future Direction

• Expected to be launched by ISRO in November 2020
• Future students working on CubeSat missions should not

neglect the importance of defining electrical interfaces