Spacecraft Thermal Control

J Meseguer, I Pérez-Grande, A Sanz-Andrés

• Publisher: Woodhead Publishing
• Year: 2012
• Print ISBN: 9781845699963
• eBook ISBN: 9780857096081
• Topic: Technology & Engineering
• Subtopic: Aeronautic & Astronautic Engineering
• Index: Technology & Engineering

Thermal control systems are an essential element of spacecraft design, ensuring that all parts of the spacecraft remain within acceptable temperature ranges at all times. Spacecraft thermal control describes the fundamentals of thermal control design and reviews current thermal control technologies. The book begins with an overview of space missions and a description of the space environment, followed by coverage of the heat transfer processes relevant to the field. In the third part of the book, current thermal control technologies are described, and in the final part, design, analysis and testing techniques are reviewed. - Provides background on the fundamentals of heat transfer which gives the reader a better understanding of the phenomenon and the way Space Thermal Control Systems work - Merges the experience of the authors in teaching aerospace engineering topics with the experience as compilers of the 'Spacecraft Thermal Control Design Data Handbook' of the European Space Agency and the development of in orbit thermal control systems for Spanish and ESA Missions - The engineering approach is enhanced with a full section on Thermal Control Design, Analysis and Testing

1

The space mission

Abstract:

The aim of this chapter is to explain some basic concepts widely employed in spacecraft design, such as the space missions, the phases of space programme development and the sharing of responsibilities among the different organizations involved in a space programme. The conceptualization of the design of such big projects, or mission architecture, in terms of mission elements is considered. The main types of space missions, and the spacecraft division into payload and platform or bus (and its subsystems), are also described.

Key words

space mission

development phases

mission types

subsystems

1.1 Introduction

Generally speaking, it can be said that a large amount of the space activities which have taken place over the last 50 years have been focused on performing services to the community in terms of scientific and commercial aims that could not have been performed by any other means.

Since the launch of Sputnik-I in 1957, space technology has been rapidly evolving, reaching a degree of complexity that could not have been imagined in its early years.

One of the problems that needs to be solved in order to successfully achieve these aims is to assure suitable thermal behaviour for all the spacecraft subsystems. This may not seem critical or problematic in the case of Earth-based equipment, but it is crucial in the space environment. The physical and technical bases for thermal control design of spacecraft are the main subject of this book.

The set of activities needed to achieve a given objective is designated as a ‘mission’. A space mission, therefore, is focused on achieving a given objective by using a space system, because, even in spite of its difficulty and complexity, it is the only feasible or suitable method.

Due to the large cost and effort needed to perform space missions, the design disciplines involved in space mission development have attained a high degree of sophistication and complexity over the years. As a first step in this complex design process, the classical approach recommends trying to define the aim of the mission in a clear but generic way.

Some examples of this ‘clear and generic’ definition are: to provide communications between two continents, TV coverage, weather forecast, global positioning services, Earth’s resources determination, crop inventory, space observation (concerning space sciences), or experimentation in microgravity conditions. In the second step these objectives should be specified to some degree, and in this way the space mission is defined by one or more broad objectives as well as the existing restrictions and limitations. These are the bases from which to start the definition of a space system which can satisfy these objectives under the established restrictions (for instance, time, cost, and performances).

It is extremely important not to substitute these generic objectives by detailed numerical requirements, because, although the objectives remain fixed over time, the numerical requirements can change depending on the state of the technology and on the way the problem is formulated and understood, which evolve with time.

1.2 Mission analysis and design

To achieve the declared mission objectives a design and analysis process is established. This process is composed of several phases which are given different names depending on the organization responsible, although the differences are not substantial.

The design and development phases of a space programme, according to ESA standards, are summarized in Table 1.1.

Table 1.1

The design and development phases of a space programme, according to ESA standards (ECSS-E-ST-10C, 2009)

Phase	Name	Associate milestones
O	Mission Analysis	MDR Mission Definition Review
A	Feasibility	PRR Preliminar y Requirements Review
B	Preliminar y Definition	SRR System Requirements Review PDR Preliminar y Design Review
C	Detailed Definition	CDR Critical Design Review
D	Production/ Qualification	QR Qualification Review R Acceptance Review ORR Operational Readiness Review
E	Utilization	FRR Flight Readiness Review LRR Launch Readiness Review CRR Commissioning Result Review ELR End of Life Review
F	Disposal	MCR Mission Close-out Review

In a more general approach the space mission life can be split into five main stages:

1. Concept development. The initial phase aimed at obtaining a definition of the space mission and of its main elements.

2. Detailed design. This is the phase where the real design is performed, and at the end a detailed definition of all the space mission components is obtained. In some cases it can also include the development of hardware or software for testing.

3. Manufacturing and qualification. In this phase, parts are manufactured, equipment is assembled to form the systems (both flight and ground), the software is developed, and the whole system verified.

4. Launch. It includes the launch campaign and the system deployment.

5. Commissioning and operations. Once the flight systems have been launched, a test and calibration phase is performed, before passing control to the organization exploiting the system.

The areas of responsibility of the key organizations that intervene in the development of a space system are:

Space system operator, which controls and maintains the space and ground facilities and resources.

End users (in scientific or governmental missions) or c...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of figures
• List of tables
• Foreword
• About the authors
• Chapter 1: The space mission
• Chapter 2: Space environment
• Chapter 3: Keplerian orbits
• Chapter 4: Conductive heat transfer
• Chapter 5: Thermal radiation heat transfer
• Chapter 6: Thermal control surfaces
• Chapter 7: Insulation systems
• Chapter 8: Radiators
• Chapter 9: Louvers
• Chapter 10: Mechanical interfaces
• Chapter 11: Heat pipes
• Chapter 12: Phase change capacitors
• Chapter 13: Heaters
• Chapter 14: Pumped fluid loops
• Chapter 15: Thermoelectric cooling
• Chapter 16: Cryogenic systems
• Chapter 17: Thermal protection systems
• Chapter 18: Thermal control design
• Chapter 19: Thermal mathematical models
• Chapter 20: Thermal control testing
• Chapter 21: Conclusion
• Index