ISIS - Innovative Solutions In Space has been awarded a phase-II Small Business Innovation Research (SBIR) contract by the Dutch research institute TNO to develop a prototype for a star tracker for nanosatellite applications.

Nanosatellites are increasingly used for technology demonstration and scientific experiments, while operational mission capabilities such as remote sensing and low data-rate telecommunications are under development.

For instance, the popular CubeSat-class of nanosatellites, until recently the exclusive domain of student projects, is rapidly maturing with standardized components and subsystems. With even complete platforms now available off the shelf, this class of nanosatellites has now been identified by the more established space community as capable platforms for scientific, commercial and even military applications.

One of the most limiting factors of using nanosatellites or CubeSats for operational missions is their relatively poor attitude determination and control capability, limiting the use of instrumentation that requires a high degree of pointing.

ISIS will now solve at least part of that problem within the scope of the SBIR phase-II contract. The company will develop a prototype for a nanosatellite star tracker that will provide accuracy better than 30 arcseconds.

The most innovative aspect of the star tracker is that it will allow for this performance within an envelope of about 50x50x100 millimetres. The sensor will be compatible with the CubeSat interface standard and the limited on-board resources available for nanosatellites.

Moreover, the sensor will be sold at a price that is compatible with the typical budgets of these small-scale satellite projects. Reduced mass, power, and cost will also allow the sensor to be used for other small satellite missions.

Key to the sensor's performance is a patented sensor head concept from TNO that allows for a very compact sensor combining multiple apertures in several directions.

This ensures that the spacecraft's attitude can still be successfully determined, even if several of the apertures are blinded by the Sun or obstructed by the Earth. The use of this technology enables the development of a sensor with inherent redundancy and an ability to provide complete attitude information from a single, standalone unit.

ISIS is active in the field of nanosatellites for three years and is an expert in this exciting branch of space engineering. The company offers a broad range of components, subsystems and services for nanosatellite developers. The company's portfolio includes spacecraft elements such as TTC systems, structural elements as well as ground stations and launch brokering services.

The addition of a miniature attitude determination sensor to the company's portfolio is very valuable. Combined with the company's own nanosatellite platform, the sensor perfectly meets the needs of the market, in which developers ask for better pointing capability for their spacecraft to enable ambitious nanosatellite missions such as formation flying and Earth observation.