A linear time-of-flight mass spectrometer is developed for the detection and chemical analysis of nanometer-sized particles originating near the Sun. Nano-dust particles are thought to be produced by mutual collisions between interplanetary dust particles slowly spiraling toward the Sun and are accelerated outward to high velocities by interaction with the solar wind plasma. The WAVES instruments on the two STEREO spacecraft reported the detection, strong temporal variation, and potentially high flux of these particles. Here we report on the optimization and the results from the detailed characterization of the instrument's performance using submicrometer sized dust particles accelerated to 8-60 km/s. The Nano Dust Analyzer (NDA) concept is derived from previously developed detectors. It has a 200 cm(2) effective target area and a mass resolution of approximately m/Δm = 50. The NDA instrument is designed to reliably detect and analyze nanometer-sized dust particles while being pointed close to the Sun's direction, from where they are expected to arrive. Measurements by such an instrument will determine the size-dependent flux of the nano-dust particles and its variations, it will characterize the composition of the nano-dust and, ultimately, it may determine their source. The flight version of the NDA instrument is estimated to be <5 kg and requires <10 W for operation.

We report the advance development of the Electrostatic Lunar Dust Analyzer (ELDA) instrument for the detection of individual low-velocity micron-size dust particles mobilized near the lunar surface, and the measurement of the dust charge, velocity vector, and mass. The first article (N. Duncan et al., Planet. Space Sci., 2011) described the measurement principle, optimized instrument geometry, and the initial testing performed on air. The full laboratory prototype of ELDA has now been completed and tested under vacuum. The numerical data analysis is improved to include gravitation and the calculation of the particle's mass. The ELDA operation principle is based on sensing a charged dust particle by an array of wire electrodes as it is passing though the instrument. Each wire electrode is connected to a charge sensitive amplifier and the velocity vector is reconstructed from the signal shapes and amplitudes. Within the instrument, a strong electrostatic field is used to deflect the trajectories of the particles. The dust mass is determined from the change in velocity measured before and after deflection. The instrument is tested using particles with 54μm mean radius and a narrow size distribution. The experimental results and the error analyses show that ELDA can measure the mass of individual particle with a factor of two even for very low signal to noise ratio.

The Stardust mission returned two types of unprecedented extraterrestrial samples: the first samples of material from a known solar system body beyond the moon, the comet 81P/Wild2, and the first samples of contemporary interstellar dust. Both sets of samples were captured in aerogel and aluminum foil collectors and returned to Earth in January 2006. While the analysis of particles from comet Wild 2 yielded exciting new results, the search for and analysis of collected interstellar particles is more demanding and is ongoing.Novel dust instrumentation will tremendously improve future dust collection in interplanetary space: an Active Cosmic Dust Collector is a combination of an in-situ dust trajectory sensor (DTS) together with a dust collector consisting of aerogel and/or other collector materials, e.g. such as those used by the Stardust mission. Dust particles’ trajectories are determined by the measurement of induced electrical signals when charged particles fly through a position sensitive electrode system. The recorded waveforms enable the reconstruction of the velocity vector with high precision.The DTS described here was subject to performance tests at the Heidelberg dust accelerator at the same time as the recording of impact signals from potential collector materials. The tests with dust particles in the speed range from 3 to 40km/s demonstrate that trajectories can be measured with accuracies of ∼1° in direction and ∼1% in speed. The sensitivity of the DTS electronics is of the order of 10−16C and thus the trajectory of cosmic dust particles as small as 0.4μm size can be measured. The impact position on the collector can be determined with better than 1mm precision, which will ease immensely the task of locating sub-micron-sized particles on the collector. Statistically significant numbers of trajectories of interplanetary and interstellar dust particles can thus be collected in interplanetary space and their compositions correlated with their trajectories.

The Stardust mission returned cometary, interplanetary and (probably) interstellar dust in 2006 to Earth that have been analysed in Earth laboratories worldwide. Results of this mission have changed our view and knowledge on the early solar nebula. The Rosetta mission is on its way to land on comet 67P/Churyumov-Gerasimenko and will investigate for the first time in great detail the comet nucleus and its environment starting in 2014. Additional astronomy and planetary space missions will further contribute to our understanding of dust generation, evolution and destruction in interstellar and interplanetary space and provide constraints on solar system formation and processes that led to the origin of life on Earth. One of these missions, SARIM-PLUS, will provide a unique perspective by measuring interplanetary and interstellar dust with high accuracy and sensitivity in our inner solar system between 1 and 2 AU. SARIM-PLUS employs latest in-situ techniques for a full characterisation of individual micrometeoroids (flux, mass, charge, trajectory, composition()) and collects and returns these samples to Earth for a detailed analysis. The opportunity to visit again the target comet of the Rosetta mission 67P/Churyumov-Gerasimeenternko, and to investigate its dusty environment six years after Rosetta with complementary methods is unique and strongly enhances and supports the scientific exploration of this target and the entire Rosetta mission. Launch opportunities are in 2020 with a backup window starting early 2026. The comet encounter occurs in September 2021 and the reentry takes place in early 2024. An encounter speed of 6 km/s ensures comparable results to the Stardust mission.

The interplanetary space probe Cassini/Huygens reached Saturn in July 2004 after seven years of cruise phase. The Cosmic Dust Analyzer (CDA) measures the interplanetary, interstellar and planetary dust in our solar system since 1999 and provided unique discoveries. In 1999, CDA detected interstellar dust in the inner solar system followed by the detection of electrical charges of interplanetary dust grains during the cruise phase between Earth and Jupiter. The instrument determined the composition of interplanetary dust and the nanometre sized dust streams originating from Jupiter's moon Io. During the approach to Saturn in 2004, similar streams of submicron grains with speeds in the order of 100 km/s were detected from Saturn's inner and outer ring system and are released to the interplanetary magnetic field. Since 2004 CDA measured more than one million dust impacts characterizing the dust environment of Saturn. The instrument is one of three experiments which discovered the active ice geysers located at the south pole of Saturn's moon Enceladus in 2005. Later, a detailed compositional analysis of the water ice grains in Saturn's E ring system lead to the discovery of large reservoirs of liquid water (oceans) below the icy crust of Enceladus. Finally, the determination of the dust- magnetosphere interaction and the discovery of the extended E ring (at least twice as large as predicted) allowed the definition of a dynamical dust model of Saturn's E ring describing the observed properties. This paper summarizes the discoveries of a ten year story of success based on reliable measurements with the most advanced dust detector flown in space until today. This paper focuses on cruise results and findings achieved at Saturn with a focus on flux and density measurements.

The Dust Trajectory Sensor (DTS) instrument is developed for the measurement of the velocity vector of cosmic dust particles. The trajectory information is imperative in determining the particles' origin and distinguishing dust particles from different sources. The velocity vector also reveals information on the history of interaction between the charged dust particle and the magnetospheric or interplanetary space environment. The DTS operational principle is based on measuring the induced charge from the dust on an array of wire electrodes. In recent work, the DTS geometry has been optimized [S. Auer, E. Grün, S. Kempf, R. Srama, A. Srowig, Z. Sternovsky, and V Tschernjawski, Rev. Sci. Instrum. 79, 084501 (2008)] and a method of triggering was developed [S. Auer, G. Lawrence, E. Grün, H. Henkel, S. Kempf, R. Srama, and Z. Sternovsky, Nucl. Instrum. Methods Phys. Res. A 622, 74 (2010)]. This article presents the method of analyzing the DTS data and results from a parametric study on the accuracy of the measurements. A laboratory version of the DTS has been constructed and tested with particles in the velocity range of 2-5 km/s using the Heidelberg dust accelerator facility. Both the numerical study and the analyzed experimental data show that the accuracy of the DTS instrument is better than about 1% in velocity and 1° in direction.

Micron and submicron-sized dust particles can be lifted from the lunar surface due to continual micrometeoroid bombardment and electrostatic charging. The characteristics of these dust populations are of scientific interest and engineering importance for the design of future equipment to operate on the lunar surface. The mobilized grains are expected to have a low velocity, which makes their detection difficult by traditional methods that are based on momentum transfer or impact energy. We describe a newly developed instrument concept, the Electrostatic Lunar Dust Analyzer (ELDA), which utilizes the charge on the dust for detection and analysis. ELDA consists of an array of wire electrodes combined with an electrostatic deflection field region, and measures the mass, charge, and velocity vector of individual dust grains. The first basic prototype of the ELDA instrument has been constructed, tested and characterized in the laboratory. The instrument is set up to measure over a velocity range 1–100 m/s and is sensitive to particles from an approximate mass range from 2×10−16 to 10−11 kg, depending on the charge state and velocity.

A dust astronomy mission aims at the simultaneous measurement of the origin and the chemical composition of individual dust grains in space. By distinguishing interstellar from interplanetary dust of cometary or asteroidal origin based on their trajectories and comparing their composition important clues on processes in the early solar system can be obtained. The dust observatory mission "Cosmic DUNE" has been defined to reach this goal with newly developed dust instrumentation. A dust trajectory sensor has been developed which is capable of obtaining precision trajectories of sub-micron sized particles in space. A new high mass resolution dust analyzer of 0.1 m(2) impact area can cope with the low fluxes expected in interplanetary space. With these instruments both novel dust measurements in low-Earth orbit and improved dust collection and sample return schemes are achievable.

A new instrument to analyze the chemical composition of dust particles in situ in space has been developed. The large target area ( approximately 0.2 m(2)) makes this instrument well suited for detecting a statistically significant number of interstellar dust grains or other dust particles with a low flux. The device is a reflectron-type time-of-flight mass spectrometer that uses only flat electrodes for the generation of the parabolic potential. The instrument analyzes the ions from the impact generated plasma due to hypervelocity dust impacts onto a solid target surface. The SIMION ion optics software package is used to investigate different potential field configurations and optimize the mass resolution and focusing of the ions. The cylindrically symmetric instrument operates with six ring electrodes and six annular electrodes biased to different potentials to create the potential distribution of the reflectron. The laboratory model of the instrument has been fabricated and tested. Hypervelocity dust impacts are simulated by laser ablation using a frequency doubled Nd:YAG laser with approximately 8 ns pulse length. The experimental data show typical mass resolution m/Deltam approximately 200.

Appropriate techniques were developed in order to address the key questions of Dust Astronomy. Space missions were proposed which carry a set of dust instrumentation (Galictic DUNE, Cosmic DUNE, ConeXpress). The payload for a dust observatory is a dust telescope, which is capable to determine the speed, mass, primary charge, trajectory and elemental composition with high accuracy of individual particles simultaneously. The accaruacies to measure the micrometeoroid characteristics are 1 degree for the dust trajectory, 1% for particle speed, a factor of 2 for particle mass, 10% for particle charge and a mass resolution above 150 for the composition of the grains. The employment of a large sensitive area of 0.1 mˆ2 allow the detection of particles in low density dust environments. This paper reports about the capabilities of the combination of a dust Trajectory Sensor and a Large Area Mass Analyzer and gives laboratory results of the Mass Analyzer.

Dust particles' trajectories are determined by the measurement of the electric signals that are induced when a charged grain flies through a position sensitive electrode system. The objective of the trajectory sensor is to measure dust charges in the range 10(-16) to 10(-13) C and dust speeds in the range 6 to 100 km/s. The trajectory sensor has four sensor planes consisting of about 16 wire electrodes each. Two adjacent planes have orthogonal wire direction. A charge sensitive amplifier ASIC has been developed with a RMS noise of about 1.5.10(-17) C. The signals from 32 electrodes are digitized and sampled at 25 MHz rate by an transient recorder ASIC (Application Specific Integrated Circuit). First tests with a laboratory set-up have been performed and demonstrate the expected performance.

Information about the make-up of the galaxy arrives in the Solar system in many forms: photons of different energies, classically collected by ground- and space-based telescopes, neutral and charged atomic particles, and solid macroscopic particles: cosmic dust particles. Dust particles, like photons, carry information from remote sites in space and time. This information can be analysed in order to understand the processes and mechanisms that are involved in the formation and evolution of solid matter in the galaxy. This approach is called ``Dust Astronomy'' which is carried out by means of a dust telescope on a dust observatory in space. The analysis of cosmic grains collected in the high atmosphere of the Earth has shown that each dust grain is a small world with various sub-grains featuring different galactic origin and evolution, which is identified on the basis of elementary and isotopic analysis. Independent information about the origin and evolution of the grains coming from the kinematic properties of the arrival trajectory would be invaluable for linking the isotopic signature of the formation of heavy elements in old stars and supernovae to distinctive regions in our galaxy, e.g. known star-forming regions. Here we present a skymap of potential dust sources together with a report on already existing lab hardware of a trajectory sensor and a large-area mass spectrometre.

Saturn's E ring is remarkable not only for its huge size. Based on optical measurements the ring was surprisingly found to mainly consist of ice particles of uniform size (radii between 0.3 and 2 microns) [Nicholson et al., 1996. Observations of Saturn's ring-plane crossing in August and November. Science 272, 509–516], though the source of the ring, the icy moon Enceladus, feeds the ring with grains having a much broader mass distribution [Spahn et al., 1999. Dynamics of dust ejected from enceladus: application to the cassini dust detector. J. Geophys. Res. 104, 24111–24120]. Because of this contradiction, the mass distribution of the ring must be closely connected to the dynamics of the ring particles which is governed by the competition of various disturbing forces acting on the grains. It was realised early that the dynamics of the charged ring particles is strongly affected by electromagnetic forces as well as by plasma drag. Understanding the implications on the ring dynamics thus requires knowledge of the electrostatic equilibrium potential of the dust grains. The charge-sensitive grid system of the cosmic dust analyser (CDA) on the Cassini spacecraft allows an in situ determination of the charge of grains bigger than 2–3 microns. Since the CDA detector determines the grain mass simultaneously with the dust charge the electrostatic potential φd can be estimated as well. Here we report the first measurement of the electrostatic potential of E ring particles. Particles detected inside the orbit of Saturn's moon Rhea were always found to be negatively charged, whereas grains outside Rhea's orbit were on a positive potential of about 3 V. Our results are in good agreement with measurements of the spacecraft potential by Cassini's radio and plasma wave science (RPWS) investigation [Wahlund et al., 2005. The inner magnetosphere of Saturn: Cassini RPWS cold plasma results from the first encounter. Geophys. Res. Lett. 32]. Our analysis implies that the CDA dust analyser (DA) mass calibration by Göller and Grün [1998. Calibration of the Galileo/Ulysses dust detectors with different projectile materials and at varying impact angles. Planet. Space Sci. 37, 1197–1206] is applicable for ice particles. We achieved a good match between our findings and the model calculations of the grain potential when using new Cassini measurements of plasma properties within Saturn's inner plasma sphere. Based on this we provide a realistic description for the grain potential needed for modelling the dynamics of Saturn's E ring.

In July 2004 the Cassini–Huygens mission reached the Saturnian system and started its orbital tour. A total of 75 orbits will be carried out during the primary mission until August 2008. In these four years Cassini crosses the ring plane 150 times and spends approx. 400h within Titan's orbit. The Cosmic Dust Analyser (CDA) onboard Cassini characterises the dust environment with its extended E ring and embedded moons. Here, we focus on the CDA results of the first year and we present the Dust Analyser (DA) data within Titan's orbit. This paper does investigate High Rate Detector data and dust composition measurements. The authors focus on the analysis of impact rates, which were strongly variable primarily due to changes of the spacecraft pointing. An overview is given about the ring plane crossings and the DA counter measurements. The DA dust impact rates are compared with the DA boresight configuration around all ring plane crossings between June 2004 and July 2005. Dust impacts were registered at altitudes as high as 100000km above the ring plane at distances from Saturn between 4 and 10 Saturn radii. In those regions the dust density of particles bigger than 0.5μm can reach values of 0.001m-3.