ESA title
Germanium recycling
Enabling & Support

Effective recycling for Germanium

14/05/2022 925 views 4 likes
ESA / Enabling & Support / Space Engineering & Technology / Shaping the Future

Germanium (Ge) has been identified as one of the major environmental hotspots of ESA’s space missions. As one of the critical raw materials the use of it (mainly driven by solar cells) is a major contributor to mineral resource depletion.
Today, Germanium is used as a growth template for certain solar cells. While the thickness of the Germanium on a solar cell level is extremely thin, around 140μm, actually only 10-20μm are actively being used. The rest is structural.
An activity with TDE and Umicore, Belgium, has developed and 

implemented a recycling process for Germanium with specific steps for areas where recycling is not currently done, such as the thinning process of the germanium wafers used for the cells.
The activity has also developed a process for manufacturing highly efficient solar cells using alternative growth templates that allow for a significant reduction of Germanium used per cell.
In collaboration with Azur Space, a recycling path has been implemented that allows for 80% of the germanium to be recovered from the backgrinding process to thin the germanium used in a solar cell.

In addition, the first growth trials of germanium engineered substrates have been successfully performed with very promising results
Life cycle analysis studies demonstrated that implementating the proposed recycling process reduced the germanium consumption by 25% in total, but more could still be achieved.
While the impact this would have on a spacecraft’s environmental footprint is clear, the implementation of the recycling process also has economic benefits.
4000128156 closed at the end of 2021.