Design Integration and Test

The Design, Integration and Test section is by far the largest with a staff of around a dozen engineers. A wide range of areas of expertise exists. These exploit advanced techniques and devices to address the diverse requirements of differing space missions. Different space missions call for very different design approaches. For example some call for very high data rates whereas some require extreme miniaturisation and very low power consumption. All missions require high reliability techniques and to be engineered for the space vacuum and launch vibration environments. Most missions require radiation tolerant systems, the level of tolerance being dependent on the orbit and mission duration.

Electronic ground support equipment (EGSE) for the missions is invariably computer based and calls for different design techniques again. The electronic systems for instruments on most missions follow a common flow of functions. This flow typically begins with a low level analogue signal from some form of sensor and ends with a digital and power interface to the spacecraft central services. Housekeeping (instrument health and status) data are normally collected as well as 'science' data. We are not normally involved in the spacecraft bus sub-systems (attitude and orbit control, telemetry and telecommand, primary power system etc).

Electronic sub-system functions commonly found in space science instruments are as follows:

Low noise and/or high speed amplification.

Analogue signal conditioning including: charge sensitive pre-amplifiers, general amplification, pulse shaping, bandwidth control, sample/peak detect & hold.

Signal conversion including: analogue to digital varying from high precision to high speed, analogue processing such as ratiometric division.

Clock waveform generation for the readout of CCDs and other image sensors.

Digital processing both in discrete logic and microprocessor based systems. These systems can be very specific such as to decode the position of a photon arriving on a position sensitive detector or can be more general purpose such as the command and data handling system which commonly exercises overall instrument control and the interfaces to the spacecraft. High speed systems and high density FPGA systems are frequently implemented.

Power conditioning, both low voltage (typically around the 50W level) and (low power) high voltage supplies, typically between 3 and 10kV. These all need to provide isolation and to adhere to very stringent EMC requirements.

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This page last modified 18 September, 2007 by Martin de la Nougerede