UK Launches Advanced TopSat Micro-Satellite Experiment
TopSat is a low cost, high capability micro-satellite designed and built by a QinetiQ-led consortium of British companies. After some initial launch delays, it was successfully launched on October 27, 2005 from the Plesetsk launch site in Northern Russia, along with micro-satellites from China, Iran, and Russia. The launch was the culmination of a project that began in 2000 and was jointly funded by the British National Space Centre (BNSC) and the UK Ministry of Defence.
TopSat is attracting increasing interest from international government and commercial interests because it’s designed to provide 2.5 meter resolution imagery at about 20% of the cost of larger satellites with similar capabilities. It is part of Britain’s larger Micro Satellite Applications in Collaboration (MOSAIC) program.
The platform consists of an advanced optical camera, which is able to collect 17 x 17 km images of the earth with a black and white resolution of 2.86 metres and a colour resolution of 5 metres. This optical camera is integrated with an agile micro-satellite platform to permit pitch compensation manoeuvres, allowing imaging of low illumination scenes.
TopSat will be able to address many remote sensing applications including disaster relief, environmental monitoring, crop management, land use, border control and security use. The system also includes the RAPIDS system for direct reception of data in the field using a low-cost satellite dish on a small vehicle. Data can be downloaded to other mobile or fixed ground stations using the CCSDS communications standard within hours, increasing the versatility of the system.
A constellation of 3-4 TopSat satellites could theoretically image almost any point on the Earth at least once a day, subject to cloud conditions, opening up the potential for very low latency imagery which is extremely cost effective to deliver. DID did not find any data regarding satellite lifespan, however.
The MOSAIC program was intended to fully exploit the UK’s world leading capability in small satellites, and to stimulate the development of key small satellite technologies and payloads. Qinetiq notes that:
“The TopSat telescope packs the long focal length and large optical aperture required for 2.5m imagery into a novel, compact, three-mirror off-axis design. Push-broom imaging with a linear CCD is used, with time delay integration available to permit imaging under poor illumination conditions. Whole spacecraft body steering is used to access a broad swath to allow rapid revisit times. The combination of a very low mass, high performance camera and steered using a low mass, agile bus results in a dramatic performance / cost ratio.”
Space-Technology adds that:
“Topsat uses a low mass telescope mounted on a proven low-cost microsatellite platform. Image data can be downloaded to a mobile ground station, positioned locally, then delivered directly to the user… Alignment and focus are maintained by the high thermal stability of the monocoque construction, fabricated in low mass carbon fibre reinforced plastic composite materials. To maximise coverage and sensitivity whilst minimising size and mass, push-broom imaging with a linear CCD is used.”
QinetiQ’s lead role has involved overall systems design and programme management, and also provided the major payload electronic sub-systems. Other partners in the project include Surrey Satellite Technology Ltd for the platform, satellite integration and the telecommand and control system; CCLRC Rutherford Appleton Laboratory (RAL) for the high performance camera; and Infoterra Ltd, who is developing the market for TopSat data products.
The launch had suffered a minor delay on September 27, 2005, as a result of failures in Iran’s “Sina-1” micro-satellite (constructed by Polyot, in Omsk). Other micro-satellites that were part of the launch included China’s BLMIT-1, the European Space Agency’s SSETI -Express, and Russia’s Mozhaets-5.
UPDATE: DID returns to TopSat with news that it’s transmitting, and an example picture.