# Implementation of a Cryogenic Facility for Space Debris Analysis
## 5 Experimental Methods and Results
### MLI Debris Generation after ATOX Exposure  
During ATOX exposure, a sample tray was positioned below the sample holder (to catch debris); see Figure 20. Each tray was analyzed with scanning electron microscope (SEM)-based energy-dispersive X-ray spectrometry (EDX). Figure 20 depicts the position of the sample trays (in relation to the sample holder). Three sample trays were positioned below the sample holder; each sample tray was a silicon wafer.  
Figure 20: (**a**) ATOX (atomic oxygen) sample holder. (**b**) Silicon sample trays.  
In the case studies, four types of images are presented, namely SEM images, EDX layer image, EDX single-element image, and EDX-detected spectrum. Examples of these images are presented in Figure 21.  
By analyzing individual particles' compositions, one can identify what the contamination is from the ATOX system (generation of iron particles by laser ablation) and what samples originate from particles/fibers.  
Table 8 presents LEO sample paints' compositions.  
Figure 21: Examples in case studies. (**a**) SEM image, (**b**) EDX layer image, (**c**) EDX single-element image, and (**d**) EDX spectrum.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Samples** & **Substances** & **Elements** \\ \hline PUK & Black polyurethane paint & C and N \\ \hline \multirow{3}{*}{PSB} & White silicate paint; binder is \\  & potassium metasilicate; pigment is \\  & zinc orthotitanate & \\ \hline \multirow{3}{*}{SG121 FD} & White silicone paint; binder is \\  & polydimethylsiloxane resins; \\  & pigments are zinc oxide calcined at \\  & 600 \({}^{\circ}\)C, sodium perforate coated & \\ \hline MLI LEO—1 & Kapton, VDA, polyester, Mylar & C, N, O, and Al \\ \hline MLI LEO—2 & ITO/SiOX/Kapton/VDA, Dacron, \\  & Mylar, VDA & I, Sn, O, Si, C, and O \\ \hline MLI LEO—3 & ITO/Teflon/Silver/Inconel, Dacron, \\  & Kapton, VDA, Mylar & I, Sn, O, Si, C, and O \\  & & Inconel may include Ni, Cr, \\  & Kapton, VDA, Mylar & Fe, Mn, Cu, Al, Si, C, and S. \\ \hline \hline \end{tabular}
\end{table}
Table 8: LEO sample pains’ compositions.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Case Study** & **Probable Origin of Debris** & **Particle Size/Fiber Length** & **Composition and Notes** \\ \hline
1 & PSB & 10 \(\mu\)m\({}^{2}\) & Ti, O, and Zn \\ \hline
2 & PSB & 6.25 \(\mu\)m\({}^{2}\) & Ti, O, and Zn \\ \hline
3 & MLI isolator material or & \\  & contamination & 231 \(\mu\)m length & Organic fiber, \\  & contamination & & O, and C \\ \hline
4 & MLI isolator material or & \\  & contamination & & Organic fiber, \\  & contamination & & O, and C \\ \hline
4 & Inconclusive & & K and O \\ \hline
5 & MLI isolator material or & \\  & contamination & & O, and C \\ \hline
6 & Inconclusive & 12 \(\mu\)m\({}^{2}\) & K, Ti, O, and Zn \\ \hline
7 & Inconclusive & & Fiber, O, C, and F \\ \hline
9 & VDA from MLI & \\  & or Al from sample holder & 24 \(\mu\)m\({}^{2}\) & AL and O \\ \hline
10 & MLI isolator material or & \\  & contamination & 171 \(\mu\)m\({}^{2}\) & Organic fiber, O, and C \\ \hline
11 & VDA from MLI & \\  & or Al from sample holder & 20 \(\mu\)m\({}^{2}\) & AL and O \\ \hline
14 & Inconclusive & 18 \(\mu\)m\({}^{2}\) & C and F \\ \hline
15 & Inconclusive & 28 \(\mu\)m\({}^{2}\) & C, O, Cu, and Zn, fiber from MLI 3 (Inconel composition to be \\  & & & investigated) \\ \hline
16 & PSB & 4 \(\mu\)m\({}^{2}\) & Zn and Ti \\ \hline
17 & MLI isolator material or & \\  & contamination & 37.2 \(\mu\)m\({}^{2}\) & Organic fiber, O, and C \\ \hline \hline \end{tabular}
\end{table}
Table 9: LEO ATOX particle size or fiber length and origin identification.