Star Trackers Lights the Way
The concept of a Star Tracker probably can be traced back to the early sailors who used to navigate the open seas. The concept is they use star field patterns in order to tell them where they’re pointed, while they are sailing from east to west or north to south, whatever direction they were going. The Star Tracker is a lot more complicated in that it uses the entire star field pattern to provide attitude knowledge or, in the lay men’s term, more of the direction in which the spacecraft is pointing while it is orbiting the Earth or doing wherever its science mission requires it to do. So, essentially, it’s an optical device to access the eyes of the spacecraft. The Star Tracker was built for the Lunar Reconnaissance Orbiter and the Solar Dynamics Observatory, both NASA missions in Florence, Italy by Galileo Avianica. They write their own software used to operate the star trackers, ground all of their optics, fabricate the structures, and assemble and test the electronics. Once the star trackers are assembled, Galileo Avionica works with NASA engineers in order to ensure that the star trackers are built to achieve their performance requirement as well as their environmental requirement. The LRO and SDO missions both use two star trackers for redundancy, so that if you get a fair unit in one, the second star tracker will be used as the backup. Also, the use of two star trackers provided added or increased performance accuracy so that the spacecraft will have a more accurate knowledge of where it’s pointed while its orbiting either the moon, the Earth, or the Sun. NASA is an educational extension of the government. Through all the information we get from all our various missions, we learn things about our Earth, space, how space effects Earth, and our changing environment. All of these things are important to everyone in the world, whether we know it our not, and the importance of star tracker, is they act as the eyes of the satellite to let the satellite know where its going in order to get the information we need.