Sira to build tiny spectrometer for better environmental monitoring

Citation

(1998), "Sira to build tiny spectrometer for better environmental monitoring", Sensor Review, Vol. 18 No. 3. https://doi.org/10.1108/sr.1998.08718cab.012

Sira to build tiny spectrometer for better environmental monitoring

Sira to build tiny spectrometer for better environmental monitoring

Keywords Aerospace, Environment, Environmental monitoring, Sira

Sira Electro-Optics has won financial support from the British National Space Centre (BNSC) to build the world's smallest satellite-based imaging spectrometer, which is expected to give the UK a technological lead in monitoring pollution and the environment from space.

The instrument, known as CHRIS (compact high-resolution imaging spectrometer), is capable of observing the Earth from a miniature satellite (minisat) with a ground resolution of just 25 metres, yet it uses less power than a camcorder and could fit into a briefcase.

BNSC's support was confirmed as John Battle, Minister for Science, Energy and Industry, was visiting the Chislehurst-based advanced instrumentation and space hardware company.

He said: "This project is an important step forward in the UK's ability to monitor pollution and climate change. Future designs of the instrument could also be used closer to Earth for aerial monitoring of vegetation and our use of natural resources, and even in a portable ground-based capacity."

"Sira's proposal was judged the best in Europe and we are delighted to be providing support for such a worthwhile project."

Sira won a competition organised by the European Space Agency (ESA) for the opportunity to provide an advanced, but highly compact instrument to be taken on board a new type of ESA minisat, which will be much smaller and more agile than its predecessors.

Called PROBA (project for on-board autonomy) and intended to be launched in the year 2000, the ESA satellite will demonstrate how future spacecraft could become increasingly autonomous, especially in the areas of platform control, data handling and storage systems.

A separate agreement between Sira and ESA will cover the supply and operation of the CHRIS payload.

Sira's chief executive, Richard Brook, said winning the competition was a terrific opportunity to demonstrate Sira's expertise in designing and building optical instruments for pollution and environmental monitoring.

"PROBA will allow us to demonstrate CHRIS, which in the longer term has enormous commercial potential and could represent an important technology lead for the UK. But without BNSC's support we could not have afforded to shoulder the full financial risk of building the instrument ourselves", he said.

"This mission could give rise to a new generation of compact instruments providing cost-effective access to widespread data about land-use, pollution and other environmentally- important parameters", Brook added.

BNSC and Sira will be co-funding the construction, testing and deployment of CHRIS, which will have a total cost of about £1.5 million.

Consuming less than 10W of power and weighing under 15 kilograms, CHRIS will fit neatly on PROBA without compromising the satellite's power and mass constraints. It will operate across 19 spectral bands within the visible region of the spectrum (400-1,050 nanometres). CHRIS will also be capable, however, of a ground resolution of just 25 metres while observing a strip of the Earth up to 19 kilometres wide as PROBA passes overhead.

Furthermore, future CHRIS payloads could operate at wavelengths out to about 300 nanometres in the infra-red region of the spectrum.

Two key design features make the combination of CHRIS and PROBA potentially more powerful for Earth-observation, particularly of land use, than previous satellite-based instruments.

First, PROBA will be capable of pointing itself to view particular areas of interest. Target areas of vegetation will be viewed from different orbital positions, thereby giving a better indication of ground conditions.

More traditional Earth-observation instruments are not capable of adjusting their attitude as they fly over a target area, and are only capable of fixed viewing angles.

Second, PROBA's attitude will be constantly adjustable from the ground, providing CHRIS with the flexibility to review targets in response to its findings. Furthermore, the spectral bands in which CHRIS is observing back-scattered solar radiation from different types of vegetation will be selectable from the ground.

On-board programmable digital electronics will control the charge-coupled device (CCD) imager and its data output.

Sira has patented the spectrometer design, which makes use of a novel geometric layout. The resulting configuration is simple, passive and compact, measuring just 60 x 200 x 800mm.

Imaging spectrometers generate more data faster than any other type of space-based instrument. At the same time, they are increasingly being used in scientific missions to measure parameters of environmental concern.

Sira played a significant part in designing MERIS, an imaging spectrometer for monitoring land and water pollution, which will soon be deployed on ESA's ENVISAT environmental-monitoring satellite.

For further information contact Sandy Deane, at Sira Electro-Optics Ltd, South Hill, Chislehurst, Kent BR7 5EH, UK. Tel: +44 (0)181 467 2636.