IMPACTS ON THE HUBBLE SPACE TELESCOPE WIDE FIELD AND PLANETARY CAMERA 2: MICROANALYSIS AND RECOGNITION OF MICROMETEOROID COMPOSITIONS. A. T. Kearsley 1 ,

Postflight surveys of the Wide Field and Planetary Camera 2 (WFPC2) on the Hubble Space Telescope have located hundreds of features on the 2.2 by 0.8 m curved plate (Fig. 1), evidence of hy-pervelocity impact by small particles during 16 years of exposure to space in low Earth orbit (LEO) [1,2]. Fig. 1. a) WFPC2 is removed from the Hubble Space Telescope during service mission 2 (STS-125) in 2009; b-d) diverse sizes of impact structure on WFPC2 cores. The radiator has a 100 – 200 µm surface layer of white paint, overlying 4 mm thick Al alloy, which was not fully penetrated by any impact. Over 460 WFPC2 samples were extracted by coring at JSC, using the method of [2]. About half were sent to NHM in a col-laborative program with NASA, ESA and IBC. The structural and compositional heterogeneity at microme-tre scale required microanalysis by electron and ion beam microscopes to determine the nature of the im-pactors (artificial orbital debris, or natural micromete-oroids, MM). Examples of MM impacts are described by [3,4]. Here we describe the development of novel electron beam analysis protocols [5], required to rec-ognise the subtle traces of MM residues.