Hypervelocity capture of particles in aerogel: Dependence on aerogel properties

Burchell, Mark J. and Fairey, Sam A. J. and Foster, Nicholas J. and Cole, Mike J. (2009) Hypervelocity capture of particles in aerogel: Dependence on aerogel properties. Planetary and Space Science, 57 (1). pp. 58-70. ISSN 0032-0633. (doi:https://doi.org/10.1016/j.pss.2008.11.004) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://dx.doi.org/10.1016/j.pss.2008.11.004

Abstract

Capture of high-speed (hypervelocity) particles in aerogel at ambient temperatures of 175–763 K is reported. This extends previous work which has mostly focussed on conducting experiments at ambient laboratory temperatures, even though aerogels are intended for use in cosmic dust capture cells in space environments which may experience a range of temperatures (e.g., the NASA Stardust mission which collected dust at 1.81 AU and putative Mars atmospheric sampling missions). No significant change in track length (normalised to impactor size) was found over the range 175–600 K, although at 763 K a significant reduction (30%) was found. By contrast, entrance hole diameter remained constant only up to 400 K, above this sudden changes of up to 50% were observed. Experiments were also carried out at normal laboratory temperature using a wide range of aerogel densities and particle sizes. It was found that track length normalised to particle size varies inversely with aerogel density. This is a power law dependence and not linear as previously reported, with longer tracks at lower densities. Glass projectiles (up to 100 ?m size) were found to undergo a variety of degrees of damage during capture. In addition to the well known acquisition of a coating (partial or complete) of molten aerogel the mechanical damage includes pitting and meridian fractures. Larger (500 ?m diameter) stainless steel spheres also showed damage during capture. In this case melting and ablation occurs, suggesting surficial temperatures during impact in excess of 1400 °C. The response of the aerogel itself to passage of particles through it is reported. The presence of fan-like fractures around the tracks is attributed to cone cracking similar to that in glasses of normal density, with the difference that here it is a repetitive process as the particles pass through the aerogel.

Item Type: Article
Uncontrolled keywords: Aerogel; Hypervelocity; Capture; Cosmic dust
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Faculties > Sciences > School of Physical Sciences
Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: Mark Burchell
Date Deposited: 05 Dec 2013 12:55 UTC
Last Modified: 05 Jan 2015 13:48 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/37228 (The current URI for this page, for reference purposes)
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