Externship within Micos Engineering GmbH
My externship project with Micos Engineering, GmbH was focused on blackbody light sources for the calibration of Earth observation satellites used to monitor the weather. Unlike astronomical instruments, instruments on Earth observation satellites cannot look at standard stars for calibration and must instead have on-board calibration light sources.
A perfect blackbody is an ideal calibration source because its emission across all wavelengths is well characterized, assuming you know the blackbody temperature. However, a classic blackbody, i.e., a hollow cube or sphere with a perfectly emissive inner surface and a small entrance hole for viewing, is not practical on a satellite due to the volume it occupies. Instead, a blackbody light source with a flatter geometry is needed for these purposes. For example, this picture shows a commercial blackbody light source from a French company HGH that uses a plate with small pyramid structures to mimic a cavity blackbody while taking up less volume. Furthermore, the assumption of knowing the blackbody temperature is not realistic either, because there is error in the chain of sensors and electronics used to measure the temperature and a practical limit to how many temperature sensors can be placed on the blackbody light source. Thus, designing these blackbody calibration light sources is a challenging engineering task.
Figure 1: Image of a commercially produced blackbody light source from HGH, in France. The micro pyramid structures highlighted in the zoomed in image mimic the emission from a classic cavity blackbody but take up much less volume. For instruments on a satellite, custom flat blackbodies must be designed to meet the specific performance and interface requirements for the instrument. Image courtesy of HGH.
My externship work was divided into two projects: (1) working on developing a new blackbody light source and (2) performing laboratory tests of a flight blackbody light source for an upcoming weather satellite.
The first project was started from the very beginning, and so allowed me to see the steps of a space engineering project beginning from the kick-off. My initial tasks were to go over the requirements for the blackbody light source as specified by the customer in order to make sure we understand the requirements and to assess whether we can meet the requirements. I then performed simulations of the blackbody light source to trade-off between different conceptual designs.
The second project of my externship was to perform laboratory tests for blackbody light source that will be flown on an upcoming weather satellite. This project is in the final assembly, integration, and testing phase and so participating in these tests was very complementary to my first project as it let me see a space engineering project towards the final stages. I learned how to use the clean room and temperature-controlled vacuum chamber facilities at Micos, which were similar to systems I had used for ground-based astronomical instrumentation in the past but with even more stringent requirements for cleanliness and precision.
The externship project was extremely successful as a way for me to learn what it is like to work the space industry. I was able to get a sense of the engineering process at a few different stages and see the differences between academia and industry firsthand. I am very happy that I had this opportunity and want to thank Micos very much for the chance to work with them for the externship and PlanetS for funding this experience.
Since finishing my postdoc contract at ETH, I have been employed by Micos as an engineer and I believe the externship was a key contributor in me receiving this position.
Figure 2: Image of the temperature-controlled vacuum chamber at Micos used for testing components for satellites. Image courtesy of Micos.
Extern/Author: Dr. Anna Boehle
Host Institution: Micos Engineering GmbH, Dübendorf
