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Transcript

Electronics and Eco-design

UKSA Space Cluster Microcredentials

1. What are CubeSats?Gain an understanding of the concept behind the CubeSat standard and investigate their applications.2. Example CubeSat Architecture.Gain an overview of CubeSat design requirements and a typical component make-up.

learning objectives

01

Module 1-Intro to Vehicle Systems

Throughout this module of study - and the Electronics and Eco Design Microcredential as a whole - we will discuss some of the concepts behind the design and construction of space vehicles (in our case, satellites). In order to provide a consistent platform for our discussions the concept of the CubeSat will be used as our 'vehicle' of learning. As such, this training document starts with a high-level discussion of the CubeSat architecture and specification and will include an overview of relevant documentation and investigations of example hardware platforms.

Space vehicle systems

Image: ESA - CC BY-SA IGO 3.0

+ INFO

A CubeSat is a miniaturized satellite vehicle with a standard form factor of 100mm x 100mm x 100mm with a mass of 2Kg or less. This is the smallest standard size described as a single unit (1U). This form-factor can be combined to implement larger, more useful vehicles. These can be 3U, 6U or 12U vehicles. The CubeSat reference design was proposed by Professors Jordi Puig-Suari of California Polytechnic State University and Bob Twiggs of Stanford University in 1999. The original concept was not intended to be standardised but it has emerged as such over subsequent years.

What are cubesats?

The CubeSat Standard has been designed to provide several benefits for low cost development and launch of (typically) Low Earth Orbit satellite vehicles. These benefits include:

  • Highly Modular.
  • Highly Integrated.
  • Significant use of Commercial Off The Shelf (COTS) components.
…resulting in decreased time to delivery and cost.

Why Cubesats?

Image: ESA - CC BY-SA IGO 3.0

CubeSats are also extremely flexible in their applications and are commonly used for:

  • Technology Demonstrations
  • Low cost space applications
  • Education

Why Cubesats?

Investigation 1

Investigation 2

Investigation 3

Use the following websites and/or your own resources to investigate examples of previous CubeSat missions. On completion take the opportunity answer the quiz questions on CubeSat technology.

investigate cubesats

Throughout this Micro-credential we will discuss satellite architecture using a 3U CubeSat as an example. Here we introduce the sub-systems found within this typical CubeSat to gain a basic understanding of their layout and requirements. Although CubeSats are designed to be relatively simple space exploration vehicles, their overall architecture features would be expected to be found on any typical Low Earth Orbit or Deep Space vehicle.

An Example CubeSat Architecture

+ INFO

All Electrical/Electronic systems require power with our CubeSat being no different.One of the most size, power and cost efficient power sources for space vehicles are Solar Panels. These can be mounted to the external body frame (as seen here) or deployed as expanding panels providing a larger surface area. The Electrical Power System (EPS) is designed to control and monitor the power generated from the Solar Panels to ensure safe delivery to the satellites subsystems. This includes on-board battery management, multi-rail voltage regulation and space craft monitoring.

Solar panels + eps

The On-Board Computer provides much of the processing capability for our CubeSat. This OBC will consist of a microprocessor/controller board which will include volatile and non-volatile memories, sensor interfaces and backplane connectivity to allow interfacing with other systems such as the payload. Often, the OBC software manages the vital functions including attitude and orbit control, tele-commands, telemetry gathering, on board time synchronisation and failure detection. As with many CubeSat subsystems the OBC is commonly a COTS based hardware which can be adapted for the manufacturers specific use case.

On-Board Computer (OBC)

All but the most simple CubeSat designs will need to communicate with Ground Station(s). Communications can either be Uni-Directional or Bi-Directional depending on the use-case. Uni-Directional communications operation would be used if no command data is required to be sent (Downlink only). However, it is likely that some command data is required to be transmitted to the satellite (Uplink) during its lifetime necessitating Bi-Directional communications. There are two types of systems in use: Radio Frequency (RF) and Free Space Optical (FSO) also known as ‘lasercomm’. For Cubesat we will focus on RF. The satellite communications system is made up of radio hardware, software and a separate antenna.

communications (comm)

To ensure functional operation of our Cubesat it will require that the vehicle has the correct orientation (attitude) throughout its flight. This enables payload (cameras/sensor equipment), RF antenna… etc to point to object-of-interest critical for the mission. It is vital for the satellite not to lose control (tumble). The Attitude Determination and Control System is a series of components designed to sense and adjust the orientation of the satellite.

Attitude Determination + Control System (ADCS)

Typical ADCS may comprise Sun or Star Trackers or 3-axis Magnetometers to sense orientation against an external frame. With orientation detected, actuators are used to make corrections where required. Reaction Wheels, Magneto Torquers and Thrusters as well as others can be used.Cubesat ADCS are often purchased as COTS assemblies.

Attitude Determination + Control System...continued

Image: Phonesat - CC BY 2.0 DEED

The payload is simply the device(s) which are going to carry out the main mission of the Cubesat. This can range from earth observation equipment (weather, landform, transport) to space observation.

payload

Investigation 4

Investigation 5

Investigation 6

Use the following websites and/or your own resources to investigate examples of previous CubeSat missions. Once complete answer the following questions on CubeSat Architecture.

Investigate CubeSat Architecture

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Please continue to the next section of the course.

THANK YOU!