A star sensor onboard a satellite determines the satellite’s attitude in space by identifying the stars in its field of view (FOV). The advantage of a star sensor over other sensors such as magnetometers, sun sensors, etc. is that it provides more accurate orientation information for the satellite to order a few arc seconds to microarc seconds, depending on the star sensor model.

In recent years, CubeSats and small satellite missions have exploded in popularity. These missions use commercially available components for their design and development, but the typical cost of a commercially available star sensor often exceeds the total budget for a CubeSat.

A stellar sensor has been created by Indian Institute of Astrophysics (IIA) scientists and collaborators for use in astronomy and small satellite-based CubeSat missions. This star sensor, called StarBerry-Sense, is based on commercial/off-the-shelf (COTS) components and costs less than 10% of those on the market. The instrument’s central processing unit is the Raspberry Pi, a single-board Linux computer popular with electronics hobbyists.

This star sensor is cheap. It is developed from off-the-shelf components that can help small satellite missions of the CubeSat class find their orientation in space.

Bharat Chandra, a Ph.D. scholar at IIA and the study’s first author, said: “We hooked up some highly optimized algorithms to a Raspberry Pi and turned it into a powerful star sensor called “StarBerry-Sense.” We were able to show that instruments built from readily available components can be qualified for space.

The main advantages of the system are its low cost and rapid development cycle using easily accessible COTS components. The modular design makes it easy and quick to adapt to different needs. While StarBerry-Sense is designed for space applications, a modified version will communicate with the Major Atmospheric Cherenkov Experiment (MACE) at the Indian Astronomical Observatory (IAO), Hanle, Ladakh.

The star sensor has passed the vibration and thermal vacuum tests required before it can be launched and used in space. These tests were conducted in-house at the environmental testing facility at IIA’s CREST Campus in Hosakote.

The entire setup is housed in a protective aerospace-grade aluminum enclosure. StarBerry-Sense takes pictures of the night sky and identifies the stars by comparing their positions to an internal database of prominent stars. The information is then used to determine the area of ​​the sky the star sensor is viewing, which helps determine the orientation of the satellite.

Magazine reference:

Bharat Chandra P, Mayuresh Sarpotdarc, Binukumar G. Naira et al. Low Cost Raspberry Pi Star Sensor for Small Satellites. Journal of Astronomical Telescopes, Instruments and Systems. DOI: 10.1117/1.JATIS.8.3.036002