Extended Data Fig. 3: APT data from Itoakwa particle RA_QD02_0279.

The APT needles extracted from the front face of Itokawa particle RA_QD02_0279 shown in Extended Data Fig. 1E (A–C) and Extended Data Fig. 1G (D–F) and from the back face shown in Extended Data Fig. 2F (G–I) and Extended Data Fig. 2H (J–L). All data extend from the Cr protective layer (grey spheres) through RA_QD02_0279’s space weathered surface into unweathered olivine. (A, D, G, and J) APT measurement of the 3D distribution of Cr (grey spheres) and OH (teal spheres). (B, E, H, and K) APT measurement of the 3D distribution of Cr (grey spheres) and H₂O (blue spheres) ions. (C, F, I, and L) Concentration of ions in atomic percent (at. %) with depth across the Cr capping layer (Cr, grey shaded region) space weathered rim (SW, blue shaded region) and the non-space weathered olivine (Ol, brown shaded region) revealing variations in the abundances of Cr (grey line), H (yellow line), OH (green line) and H₂O (blue line) ions. Line widths have been adjusted to represent the 1 sigma uncertainty and depth profiles are absolute abundances not relative concentrations (Supplementary Data 1). The boundary between the Cr and SW layer is marked by a vertical dashed red line and the boundary between the SW and Ol layer is marked by a vertical black dashed line.