Great news: We were finally able to receive the flight models of our Star Tracker System from DTU Space, the national space institute of Denmark! With this we have received all, but one last part of the attitude control equipment we purchased externally.

Being the Flying Laptop’s attitude sensor system with the highest accuracy, the star tracker system consists of two camera head units (CHUs) and one Data Processing Unit (DPU). As the names imply the CHUs are small cameras that take pictures of the stars and forward them to the DPU. The DPU processes the pictures and calculates the attitude (the direction the camera is facing), using an internal star catalog. This calculation is very precise, allowing for an accuracy of ~2 arcsec (one arc second is 1/3600 of a degree). Unfortunately, the required processing power for a picture can be quite high, which results in a time gap between the actual moment the picture is taken and the moment the On-Board Computer receives the information. This is a problem for our most complex attitude control: the target pointing mode, with rates of the satellite of up to 1.2 degree/s, leading to an offset of up to 2400 arcsec.

However, by using an in-house developed Enhanced Kalman filter (EKF) our simulations show that we are able to achieve a pointing knowledge (the accuracy, with which we know our attitude) of ≤ 7 arcsec ( or 0.00194 deg), which corresponds to an error of 20m in a distance of 600km. With this we are able to achieve a pointing accuracy (the accuracy with which we can point in a specific direction) for the target pointing mode of below 70 arcsec.
As mentioend in the beginning, we are still waiting for a little tidbit: DTU has developed a CHU with an integrated MEMS-based rate unit, called IRU. Measuring the rate of the satellite and interpolating between each picture allows for an even greater accuracy. The Flying Laptop will be the first satellite to feature this IRU and we are excited to see, what accuracy we may be able to achieve in the future!

Last Friday, for the Final Presentation of the Small Satellite Project WS11/12, the Phase A Studies developed by the student teams joining the contest were finally presented. The teams impressed with innovative solutions, well-founded technical knowledge and excellent presentations.

Ab dem 30. Januar 2012 fand am Institut für Raumfahrtsysteme (IRS) eine dreitägige Schulung in der Systems Engineering Software Engineering Base der Firma Aucotec statt.

Inhalt der Schulung waren vor allem die Grundstruktur und –funktionen der Software an Beispielprojekten. Der Fokus lag dabei auf dem Cable Modul, das am IRS vorrangig für die Auslegung und Visualisierung des Harness des Flying Laptop und für zukünftige Satellitenprojekte genutzt werden wird.

Die in der Industrie, unter anderem bei EADS Astrium, international verbreitete Softwarelösung rund um das Thema Systems Engineering Engineering Base steht ab sofort allen Mitarbeitern und Studenten des IRS im hauseigenen CIP Pool zur Verfügung.

Wir bedanken uns an dieser Stelle nochmals rechtherzlich für die sehr gute und kompetente Einführung und das Entgegenkommen der Hersteller-Firma Aucotec, die uns die Software zu Campuskonditionen zur Verfügung stellt.

For the manufacturing of the main structure CFRP (carbon-fiber-reinforced plastic) components of the Flying Laptop an own production laboratory has been established.

Wie in Satellitenprojekten üblich, so müssen die einzelnen Komponenten der Flying Laptop vor dem Start einige Tests über sich ergehen lassen. Diese sollen sicherstellen, dass sie während des Transports ins All an Bord der Trägerrakete keine Beschädigungen davontragen und nach dem Absetzen des Satelliten auf seiner Umlaufbahn voll funktionstüchtig sind.