Nanometer hypervelocity dust impacts in low Earth orbit

Abstract

[1] A study has been made of 60 nm thick aluminum films which have been exposed to the space environment outside of International Space Station (ISS) between 2002 and 2004. Field emission scanning electron microscopy has been used to provide high-resolution images of impact features less than 100 nm in diameter and of detailed impact morphologies at different spatial scales. Analysis of images reveals the incident directions and diameters of the impacting particles and allows separation of impacts at hypervelocity from those at lower velocities. This allows the separation of different particle populations. We find that most detected particles have been generated locally as the result of secondaries following larger impacts elsewhere on the ISS or as a result of docking maneuvers by the Progress supply module or by other spacecraft. There is also evidence for a population of dust particles incident at hypervelocity and with minimum diameters smaller than 10 nm. This particle flux of the dust particles is consistent with the expected flux of micrometeoroids with mass >10 À18 g at 1 AU and may represent the first measurement of dust particles with such small masses in near-Earth space. Future experiments to measure the flux of nanometer-scale dust particles are proposed, both passive exposure cells for retrieval and also active detectors to provide access to dust/debris populations without the requirement for experiment retrieval.

Formation and Acceleration of Nano Dust in the Inner Heliosphere

“…The estimated flux (Carpenter et al 2007) of the nano dust is consistent with the interplanetary dust distribution.…”

“…Possible observations of the nano dust near 1 AU were reported from the International Space Station (ISS: cratering in the exposure foil; Carpenter et al 2007) and from STEREO A and B spacecraft (voltage pulses;Meyer-Vernet et al 2009a).…”

“…Using the analysis of craters in the exposure foils that were located on the International Space Station for about two years, Carpenter et al (2007) postulated the detection of dust with sizes smaller than 10 nm. The other observation is reported from the wave instrument (Bougeret et al 2008) on the STEREO A spacecraft.…”

Dusty Plasma Effects in Near Earth Space and Interplanetary Medium

“…If this is the case, the mass input into the ionosphere below 400 km altitude is ∼ 2 · 10 −6 kg s −1 or 55 kg / year, which is ∼ 10 −6 or less of the meteoroid mass input. Nano dust impacts are also suspected to generate impact craters detected on a foil that was exposed to space within the Earth magnetosphere on the International Space Station ISS (Carpenter et al 2005) (also shown in Fig. 2).…”

DuneXpress

“…The Al films are supported by the interchannel walls of a microchannel plate (MCP) detector and are freestanding over the open areas of the microchannels. Electrons Filmed MCPs exposed outside of the International Space Station (ISS) have been demonstrated as highly sensitive passive detectors of nanometer scale dust particles [9,10]. AFIDD consists of four circular, MCP detectors bearing Al films with two thicknesses, 2 × 10 and 2 × 100 nm.…”