Spacecraft Manufacture and Test

Emery L Reeves, United States Air Force Academy

12.1 Engineering Data

12.2 Manufacture of High-Reliability Hardware

12.3 Inspection and Quality Assurance

12.4 The Qualification Program

12 J Spacecraft Qualification Test Row

12.6 Launch Site Operations

This chapter presents an overview of the spacecraft manufacturing, assembly, and test process and the underlying test theory. A system designer must understand this process because hardware manufacture and test heavily influence the program's cost and schedule. In addition, testing technology and special facility requirements may affect program feasibility. This chapter is oriented principally toward die construction of a single satellite or the first satellite of a production run. See Sec. 19.1 for a discussion of the "production line" approach applicable to building satellites in large numbers such as those which are a part of a large constellation.

Table 12-1 lists the names we use in this chapter to describe the parts of a spacecraft. For example, piece parts are individual parts, including transistors, integrated circuits, or mechanical parts such as housings, panels, bearings, and gears. A component is a complete unit or black box such as a transmitter, receiver, computer, or electromechanical actuator. Sometimes a functional group of parts, or assembly, is manufactured or tested together. An assembly as used here may be part of a component or may be integrated directly into the spacecraft Subsystems consist of groups of components. They may be assembled and tested as subsystems or integrated into the spacecraft as components.

TABLE 12-1. Hardware Nomenclature. Spacecraft are built up from subsystems, which are composed of components.

Piece Part

Component

Assembly

Subsystem Spacecraft

Individual part such as resistor, integrated circuit, bearing, circuit board, or housing

Complete functional unit such as a control electronics assembly, an antenna, a battery, or a power control unit

Functional group of parte such as a hinge assembly, an antenna feed, or a deployment boom

AO of the components and assemblies that comprise a spacecraft subsystem Complete vehicle

Methods for the manufacture and test of spacecraft and spacecraft components derive from the aircraft and electronics industries. But spacecraft hardware is less plentifid and less accessible for maintenance. In spacecraft production, a run of 10 is high volume and spacecraft recalls are extremely rare. Furthermore, environmental forces severely stress the hardware during launch.

The theory of type test (see Table 12-2) is a basic principle affecting the manufacture and test of spacecraft hardware. Type test theory depends on preparing and controlling complete and exact engineering data (drawings, specifications, and procedures). If the engineering data controls the hardware construction completely, all items built to the same data are equivalent and the results of any single-item test are valid for all like items. In particular, if a representative article (type test article) passes a sequence of qualification tests, all other articles built to the same engineering data should also pass. In other words, the design is qualified. We simply have to make sure articles are identical by controlling the engineering data and manufacturing processes. Less severe acceptance tests then certify proper workmanship.

TABLE 12-2. Theory of Type Testing. The type test theory is the basis for qualification testing.

Engineering data is complete and exact

Engineering data completely controls manufacture.

All items manufactured to the same engineering data are identical.

Results of qualification test for one article are valid for all articles.

Table 12-3 lists the steps in manufacturing, integrating, and testing a spacecraft As system designers, we must determine how long each step will take and identify any test or facility requirement that is risky or peculiar to the program. Above all, we should schedule qualification tests to qualify the spacecraft completely before launch. The following sections address these steps and describe important aspects of system design.

TABLE 12-3. Steps in Manufacturing, Integrating, and Testing.

Step

Description

Engineering

Data

Complete drawings and all supporting information such as material and part specifications and processing methods

Engineering data will consist of several hundred drawings for each component, specifications for each piece-part type and process, assembly drawings, and test equipment data

1. Manufacture planning

2. Parts procurement and test

3. Component assembly

4. Component acceptance test

Typical timing:

1. In parallel with engineering-data preparation

2. Mechanical parts and materials 1-6 mos Electronic parts 3-18 mos

4. 1 -3 mos; acceptance test includes functional test and environmental exposure

Qualify Component

Functional test and environmental exposure

Takes 1-6 mos, depending on complexity and fragility of component severity of environment and number of Mures

Integrate and Test Spacecraft

Mechanical assembly, functional test and environmental exposure

Takes 6-18 mos

12.1 Engineering Data

Engineering data (see Table 12-4) is drawings, specifications, and procedures. Standard formats and contents for military contracts are in MIL-STD 100 (drawings)* and MIL-STD 490 (specifications). Most aerospace companies use similar standards. Various documents combine to control the hardware manufacture. Each piece part, assembly, or component is described by its own individual drawing, and drawing call outs describe materials and processes. Drawing numbers identify parts. In the same way, drawings control assembly of parts into higher-level assemblies and identify integration hardware. Drawings also control interfaces, size, shape, and mounting provisions.

TABLE 12-4. Defining and Controlling Engineering Data.

Engineering Data

Drawings, specifications, and procedures

Role of Engineering

Produce engineering data

Role of Manufacturing

Build hardware to meet engineering data

Role of Quality Control

Ensure that the hardware is built and tested to meet

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