Development and calibration of a passive space dust collector for low earth orbit

Observation of dust and debris in the near Earth environment is a field of great commercial and scientific interest, vital to maximising the operational and commercial life-cycle of satellites and reducing risk to increasing numbers of astronauts in Low Earth Orbit. To this end, monitoring and assessment of the flux of particles is of paramount importance to the space industry and wider socio-economic interests that depend upon data products/services from orbital infrastructure. A passive space dust detector has been designed to investigate the dust environment in LEO-the Orbital Debris Impact Experiment (ODIE). ODIE is designed for deployment in LEO for ~1 year, whereupon it would be returned to Earth for analysis of impact features generated by dust particles. The design emphasises the ability to distinguish between the orbital debris (OD) relating to human space activity and the naturally occurring micrometeoroid (MM) population at millimetre to submillimetre scales. ODIE is comprised of multiple Kapton foils, which have shown great potential to effectively preserve details of the impacting particles' size and chemistry, with residue chemistry being used to interpret an origin (OD vs. MM). LEO is a harsh environment-the highly erosive effects of atomic oxygen damage Kapton foil-requiring the use of a protective coating. Common coatings available for Kapton (e.g., Al, SiO2, etc.) are problematic for subsequent analysis and interpretation of. OD vs. MM origin, being a common elemental component of MM or OD, or having X-ray emission peaks overlapping with those of elements used to distinguish MM from OD. Thus palladium coatings are proposed as an alternative for this application. To develop this technology to a flight-ready level much testing and calibration of the instrument is required to ensure it retains impactor residue and size whilst being exposed to the LEO environment. In this thesis the ODIE detector foils, Kapton coated with palladium, are evaluated to find the optimum thickness of Kapton and palladium that survives both hypervelocity impact and exposure to atomic oxygen. The hypervelocity impact experiments were performed with the Light Gas Gun at the University of Kent at 1 and 5 km/s and showed that the 25 µm Kapton foil established the best relationship between the size of the projectile and the size of the impact feature created on impact. The palladium coating was found to delaminate at thicknesses great than 30 nm and hence coatings thinner than 30 nm are recommended for remaining adhered to the Kapton post-impact. The 25 µm Kapton foil with various thicknesses of palladium coating were exposed to atomic oxygen and, based on the mass loss of the samples due to exposure, the 75 nm palladium coating performed the best with the least mass lost during exposure, although the defects on the surfaces of the foils may have affected this result. For the ODIE detector to be deployed in LEO, a Kapton foil thickness of 25 µm and a palladium coating thickness of 30 nm are the recommended parameters for the detector to address the flux of the sub-millimetre orbital debris and micrometeoroid populations

Palladium-coated kapton for use on dust detectors in low earth orbit: Performance under hypervelocity impact and atomic oxygen exposure

Observation of dust and debris in the near Earth environment is a field of great commercial and scientific interest, vital to maximising the operational and commercial life-cycle of satellites and reducing risk to increasing numbers of astronauts in Low Earth Orbit (LEO). To this end, monitoring and assessment of the flux of particles is of paramount importance to the space industry and wider socio-economic interests that depend upon data products/services from orbital infrastructure. We have designed a passive space dust detector to investigate the dust environment in LEO—the Orbital Dust Impact Experiment (ODIE). ODIE is designed for deployment in LEO for ~1 year, whereupon it would be returned to Earth for analysis of impact features generated by dust particles. The design emphasises the ability to distinguish between the orbital debris (OD) relating to human space activity and the naturally occurring micrometeoroid (MM) population at millimetre to submillimetre scales. ODIE is comprised of multiple Kapton foils, which have shown great potential to effectively preserve details of the impacting particles’ size and chemistry, with residue chemistry being used to interpret an origin (OD vs. MM). LEO is a harsh environment—the highly erosive effects of atomic oxygen damage Kapton foil—requiring the use of a protective coating. Common coatings available for Kapton (e.g., Al, SiO2, etc.) are problematic for subsequent analysis and interpretation of OD vs. MM origin, being a common elemental component of MM or OD, or having X-ray emission peaks overlapping with those of elements used to distinguish MM from OD. We thus propose palladium coatings as an alternative for this application. Here we report on the performance of palladium as a protective coating for a Kapton-based passive dust detector when exposed to atomic oxygen and impact. When subjected to impact, we observe that thicker coatings suffer delamination such that a coating of <50 nm is recommended. Analysis of atomic oxygen exposed samples shows a thin 10 nm coating of palladium significantly reduces the mass loss of Kapton, while coatings of 25 nm and over perform as well as or better than other commonly used coating

A cosmic dust detection suite for the deep space Gateway

The decade of the 2020s promises to be when humanity returns to space beyond Earth orbit, with several nations trying to place astronauts on the Moon, before going further into deep space. As part of such a programme, NASA and partner organisations, propose to build a Deep Space Gateway in lunar orbit by the mid-2020s. This would be visited regularly and offer a platform for science as well as for human activity. Payloads that can be mounted externally on the Gateway offer the chance to, amongst other scientific goals, monitor and observe the dust flux in the vicinity of the Moon. This paper looks at relevant technologies to measure dust which will impact the exposed surface at high speed. Flux estimates and a model payload of detectors are described. It is predicted that the flux is sufficient to permit studies of cometary vs. asteroidal dust and their composition, and to sample interstellar dust streams. This may also be the last opportunity to measure the natural dust flux near the Moon before the current, relatively pristine environment, is contaminated by debris, as humanity’s interest in the Moon generates increased activity in that vicinity in coming decades

The Winchcombe meteorite, a unique and pristine witness from the outer solar system.

Direct links between carbonaceous chondrites and their parent bodies in the solar system are rare. The Winchcombe meteorite is the most accurately recorded carbonaceous chondrite fall. Its pre-atmospheric orbit and cosmic-ray exposure age confirm that it arrived on Earth shortly after ejection from a primitive asteroid. Recovered only hours after falling, the composition of the Winchcombe meteorite is largely unmodified by the terrestrial environment. It contains abundant hydrated silicates formed during fluid-rock reactions, and carbon- and nitrogen-bearing organic matter including soluble protein amino acids. The near-pristine hydrogen isotopic composition of the Winchcombe meteorite is comparable to the terrestrial hydrosphere, providing further evidence that volatile-rich carbonaceous asteroids played an important role in the origin of Earth's water