# An Automatic Dry Sieving Mechanism for a Lunar Brick Payload
## 4 Conclusions  
This study explored the development of an automated system for the sieving of regolith.  
Figure 8: Percentage of blocked sieve pores comparison for mesh sizes 500 \(\upmu\)m, 250 \(\upmu\)m, and 125 \(\upmu\)m using LHS-1 simulant at a 45\({}^{\circ}\) sieve angle.  
Figure 9: Cumulative fine fraction percentage comparison for mesh sizes 500 \(\upmu\)m, 250 \(\upmu\)m, and 125 \(\upmu\)m using LHS-1 simulant at a 45\({}^{\circ}\) sieve angle.  
The prototype sieve relied on a stepper motor to achieve the natural frequency of the sieve. Moreover, the sieve was set up on an inclination to facilitate the movement of the coarse fraction out of the sieve and fine fractions through a mesh. The design allows for adaptation to varying frequencies (and accompanying amplitudes), angles, and feed rates. From the experiments conducted in this research we can conclude the following:  
* Testing with two simulants (LHS-1, LMS-1) showed differences in sieve blocking, emphasizing the need for in situ optimization to improve performance.
* Moisture had a minimal impact on sieve operation, despite its known influence on the mechanical properties of the simulants.
* Lower amplitudes increased fine fraction yield by enhancing particle-sieve interactions but also led to a higher degree of sieve blocking.
* Experiments with varying sieve angles showed that lower angles produced higher fine fractions but also increased the risk of sieve blocking.
* Testing different aperture sizes (500 \(\upmu\)m, 250 \(\upmu\)m, 125 \(\upmu\)m) confirmed that smaller apertures significantly increase sieve blocking and reduce overall efficiency.  
These findings highlight the inherent difficulties associated with processing fine particles and highlight the importance of addressing sieve blocking in designing effective remote dry sieving systems.  
Overall, the initial prototype tests yielded promising results, as evidenced by narrow error margins. The following phase involves testing and refining the sieve in a lunar gravity environment, acknowledging its dependence on gravitational forces for optimal functionality. Notably, the sieve's ability to mitigate sieve blocking shows that it functions as a promising alternative compared to other techniques proposed in the existing literature.  
All authors contributed to the study conception and design. Preparation was carried out by [PERSON] and [PERSON]. Data collection was performed by [PERSON] and [PERSON]. Analysis was performed by [PERSON] Conceptualization, [PERSON] and A.C. Supervision, B.V., A.C. and K.H. Editing were carried out by [PERSON] and A.C. The first draft of the manuscript was written by [PERSON] and all authors commented on it. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The test data can be found at [[https://drive.google.com/drive/folders/1](https://drive.google.com/drive/folders/1) UVxPx0 cCg8 uvuHltA6H2 AdAfyvTcOX-k?usp=drive_link]([https://drive.google.com/drive/folders/1](https://drive.google.com/drive/folders/1) UVxPx0 cCg8 uvuHltA6H2 AdAfyvTcOX-k?usp=drive_link) (accessed on 18 February 2025).  
The authors declare no conflicts of interest.  
The following abbreviations and symbols are used in this manuscript:  
\begin{tabular}{l l} \(\alpha\) & Sieving angle \\ \(\beta\) & Tossing angle \\ A & Tossing amplitude \\ CUMT-1 & China University of Mining and Technology Simulant number 1 \\ g & Gravity constant \\ ISRU & In Situ Resource Utilization \\ K & Toss indicator \\ LHS-1 & Lunar Highland Simulant 1 \\ LMS-1 & Lunar Mare Simulant 1 \\ n & Frequency \\ TUB8-M & Technical University Braunschweig Mare Simulant \\ TUB8-T & Technical University Braunschweig Highland Simulant \\ \end{tabular}