This book provides an informative account of the design of instruments used in rockets and spacecraft. The volume begins with a chapter introducing the basic principles of designing for the space environment. Following chapters discuss mechanical, structural, thermal and electronic design including the problems that are frequently encountered in the testing and verification of spacecraft subsystems. Important topics are described, including stress analysis, multilayer insulation, two-dimensional sensor systems, mechanisms, the structure of space optics, and project management and control. A final chapter looks towards future developments of space instrument design and addresses issues arising from financial constraints. The book contains lists of symbols, acronyms and units and a comprehensive reference list. Worked examples are found throughout the text. This volume is suitable for researchers and engineers in spacecraft and space instrument design. It will also be valuable to graduate students of physics, space science, spacecraft engineering and astronautics.

At the end of the nineteen sixties satellites characteristically had masses in the range 150 to 300 kg. By the end of the nineteen nineties many, if not most, satellites are being designed to mass budgets between one and ten metric tonnes. Satellites have expanded to fill the launchers available would be one conclusion. In fact, many changes have taken place during the past thirty years and most of these have led to a growth in satellite masses. The scientific problems being solved from space have grown more and more exacting in terms of the equipment required. As more is discovered, seemingly, more is left to be discovered and ever more sensitive instruments are demanded. Greater sensitivity usually requires large collecting areas, cooled telescopes or massive detectors, all strong factors in determining the mass of the payload. In the fields of Astronomy and Earth Observation the scientific problems seem best tackled by ‘Observatory Class’ missions in which a payload of five or ten separate instruments is compiled to provide the varied individual measurements necessary to address the mission objectives. In some cases these instruments could be launched on separate platforms if their observations could be properly coordinated, in other cases the full set of measurements must be simultaneous in space and time. Launch vehicles which are principally designed to meet the growing needs of geostationary communications satellites are available with the lift capability of many tonnes and so there has been little pressure to identify missions which can achieve the highest quality science from small, and hence inexpensive, satellites.

The temperature of laboratories in which space experiments are assembled, calibrated and tested is nominally 20°C (293 K) and it is thus not surprising that in general this is a most desirable operating temperature for that same equipment in space. There is nothing unique about this temperature. It is, within a relatively small band, a typical temperature that is experienced anywhere on the Earth's surface and, as fossil records show, has remained remarkably stable over billions of years.

The design of cryogenic, scanning Fabry-Perot interferometers for the Long-Wavelength Spectrometer on the ESA Infrared Space Observatory is presented. The interferometers were designed to provide a spectral resolving power of 10(4) over the wavelength range 45-180 µm, with the highest possible transmission efficiency consistent with this requirement. Metal meshes, custom designed with the aid of a theoretical model of metallic reflection, were used as the reflecting elements. The scanning mechanism featured a spring-suspended plate, which was servocontrolled by moving coil actuators and monitored by capacitance micrometers. The spectroscopic performance of the interferometers was measured in the laboratory and is compared with the model developed for the interferometer design. Although the measured resolving powers were somewhat lower than expected because of the laboratory measurement conditions, the transmission efficiencies were in approximate agreement with the design specification.

Development work has begun on an interchange mechanism for the pair of Fabry-Perot interferometers proposed for the Long Wavelength Spectrometer planned as one of the focal plane instruments for the Infrared Space Observatory. The two Fabry-Perot assemblies will be mounted on a balanced wheel which is to be carried on a shaft mounted in ball bearings which have been MoS 2 treated at the European Space Tribology Laboratory. Cryogenic testing is in hand at the Institute of Cryogenics, University of Southampton, UK. A ring gear on the wheel will be driven from the output pinion of a stepping motor. At a later stage in the project a choice will be made among all available cold motors with suitable performance. In the meantime, a prototype has been built of a special cryogenic permanent magnet stepping motor intended to operate on a current of a few milliamperes. The Paper describes constructional features of the drive, together with early results for the motor prototype.

The decision to include a third spacecraft, the UKS, in the AMPTE mission was made in 1981. The reasons for this are presented, together with a description of the spacecraft, its subsystems, and a summary of its early orbit performance. The UKS scientific instruments, and early results from them, are described in companion papers in this issue.

A Wolter Type I x-ray telescope, intended both for astronomical observations and to serve as a prototype module for the large area modular array of reflectors (LAMAR) mission, is now in definition study under NASA's Spacelab program. The five mirror telescope presently being designed is to have a blur circle radius of 20 arc sec and an effective area of about 400 cm2 at 1/4 keV, 200 cm2 in the 0.5 to 2 keV range, and 50 cm2 between 2 and 5 keV. Future expansion to a full ten mirror telescope will approximately double these effective areas. A rotary interchange mechanism will allow either of two imaging proportional counters (IPCs) to be placed at the telescope focus; one operating between 0.15 and 2 keV and the other optimized for the 0.6 to 6 keV energy range. During flight, the telescope will utilize an instrument pointing system for a series of observations lasting from six minutes to several hours. This investigation has dual objectives: The primary objective is scientific and involves observational study of galactic and extragalactic x-ray sources, extending the work of the Einstein Observatory to much fainter sources and to higher energies. The second objective is to provide an assessment of the cost and improved performance of utilizing Wolter Type l x-ray optics for the LAMAR mission and to extend the technology for producing these optics to still higher angular resolution and toward lower cost.

The 1.4–22.4 Å range of the soft X-ray spectrum includes a multitude of emission lines which are important for the diagnosis of plasmas in the 1.5–50 million degree temperature range. In particular, the hydrogen and helium-like ions of all abundant solar elements with Z > 7 have their primary transitions in this region and these are especially useful for solar flare and active region studies. The soft X-ray polychromator (XRP) is a high resolution experiment working in this spectral region. The XRP consists of two instruments with a common control, data handling and power system. The bent crystal spectrometer is designed for high time resolution studies in lines of Fe i-Fe xxvi and Ca xix. The flat crystal scanning spectrometer provides for 7 channel polychromatic mapping of flares and active regions in the resonance lines of O viii, Ne ix, Mg xi, Si xiii, S xv, Ca xix, and Fe xxv with 14″ spatial resolution. In its spectral scanning mode it covers essentially the entire 1.4–22.5 Å region.

The design and construction is described of a package of X-ray telescopes launched in the NASA satellite Copernicus (OAO-3), which began stellar observations in September 1972. It contains three grazing incidence reflectors covering a range of wavelengths from 0.3 to 8 nm, and having a combined collecting area of 40.9 sq cm, with angular resolutions up to 1 minute of arc. This is believed to be the first satellite application of such reflectors in stellar X-ray astronomy. A collimated detector of wavelengths 0.1-0.3 nm has a 17.8 sq cm collecting area. A visible light star tracker detects package misalignment if this should occur.