How engineering students at KTH keep track of their satellite design data

You might have heard that satellites are massive objects that weigh several tons and cost millions of dollars to launch into space. Now, imagine scaling down both size and cost until you could hold a satellite in your own hands – a miniature satellite! The so called cubesats are already revolutionizing the satellite industry by making access to space more affordable. These mini-satellites are made of one or multiple standardized 10x10x10 cm cubic units which only weigh a little more than 1 kg each. They make it affordable for small companies, universities and research centres all over the world to build their own satellites carrying custom-made experiments. In 2017, there will be over 350 cubesats launched to space and the prediction is over 400 for next year.

Artist’s rendering of a cubesat in space.

The idea of MIST is to allow students to play an active part in designing, testing and launching a cubesat satellite.

The Royal Institute of Technology (KTH) in Stockholm is building MIST or MIniature STudent Satellite – a satellite designed only by students. “The idea of MIST is to allow students to play an active part in designing, testing and launching a cubesat satellite”, says Daniel Bogado, student in Aerospace Engineering and responsible for System Budgets in the MIST project. MIST was proposed to the KTH Space Center in 2014 and the work started in early 2015. Currently the 6th team is working on the development of the satellite. Each team stays with the project for half a year.

The experiments on the MIST are from different institutes and companies with many different objectives. Two of the experiments have their focus on radiation analysis, there is one biological experiment, one experiment is testing their self-healing/fault-tolerant computer system in space, another experiment is testing a semiconductor of silicon carbide. Furthermore, there is a piezoelectric motor being tested in space, a new propulsion technology and finally a camera. All these experiments pose different requirements on the satellite making the combination of these an interesting task for the students.

3D-printed model of the MIST satellite.

It’s very important that each new team member quickly gets up to speed in all areas necessary for their work.

Although the satellite is tiny, building a cubesat is a big challenge. The biggest hurdle in the MIST project is the change in personnel involved in the project each semester, many students stay only for half a year. It’s very important that each new team member quickly gets up to speed in all areas necessary for their work. With 8 experiments the MIST satellite has a high number of custom parts for a 10x10x30 cm (3 Unit) cubesat. Keeping a clear overview about all aspects of each experiment is a major challenge, as well as keeping every team member up to date with the most recent values and what the impact is if something changes.

Valispace allows everyone on the team to have the latest results available from everyone else’s work.

The MIST team has found a solution to this challenge by using Valispace to store their engineering data. They use Valispace as the central platform for saving all data regarding power consumption, mass budget and other important characteristics of each experiment and subsystem of the satellite. This allows everyone on the team to have the latest results available from everyone else’s work and therefore make the right assumptions in their calculations and analysis.

With small satellites, mass and power constraints are very strict. You want to maximize the number of experiments and their operation time, but there is only so much power that the tiny solar panels can generate. On top of that, part of the satellite orbit is in eclipse, meaning that the Earth blocks the sunlight, and the satellite must rely on the power stored in batteries. A small change in the power consumption of an experiment can completely change the overall performance of the mission. The MIST team uses Valispace for the creation of a mass and power budget for the satellite. The stored data is used to create a power schedule for the experiments and allow for an easier overview of the system budgets, to ensure that the system is performing at its best capacity.

MIST mass budget created in Valispace.

Right now, the mechanical design of the MIST satellite is being finalized and after that the required thermal analysis of the whole system will be done. Even a small cubesat must be carefully tested before being launched into space to be sure that all experiments work as they should. Once the satellite is in space, no repairs can be done. MIST will be launched sometime after 2019. You can read more about the MIST satellite and find the newest updates on their blog.

The 6th MIST team together with the Swedish astronaut Christer Fuglesang.

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