Publications
162 results found
Hecht M, McClean J, Pike WT, et al., 2018, MOXIE, ISRU, and the History of In Situ Studies of the Hazards of Dust in Human Exploration of Mars, Dust in the Atmosphere of Mars and its Impact on Human Exploration, Editors: Levine, Winterhalter, Kerschmann, Pages: 225-252, ISBN: 978-1-5275-1172-9
Morgan P, Grott M, Knapmeyer-Endrun B, et al., 2018, A Pre-Landing Assessment of Regolith Properties at the InSight Landing Site, SPACE SCIENCE REVIEWS, Vol: 214, ISSN: 0038-6308
Golombek M, Grott M, Kargl G, et al., 2018, Geology and Physical Properties Investigations by the InSight Lander, SPACE SCIENCE REVIEWS, Vol: 214, ISSN: 0038-6308
Hurley J, Murdoch N, Teanby NA, et al., 2018, Isolation of Seismic Signal from InSight/SEIS-SP Microseismometer Measurements, SPACE SCIENCE REVIEWS, Vol: 214, ISSN: 0038-6308
McClean J, Merrison J, Iversen JJ, et al., 2018, Dust Loading and Pressure Drop of Fibrous Filters for Atmospheric In-Situ Resource Utilisation on Mars 2020, European Planetary Science Congress
Pike WT, Standley LM, Calcutt SB, et al., 2018, A BROAD-BAND SILICON MICROSEISMOMETER WITH 0.25 NG/RTHZ PERFORMANCE, 31st IEEE International Conference on Micro Electro Mechanical Systems (MEMS), Publisher: IEEE, Pages: 113-116, ISSN: 1084-6999
Panning MP, Staehler SC, Huang H-H, et al., 2018, Expected Seismicity and the Seismic Noise Environment of Europa, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 123, Pages: 163-179, ISSN: 2169-9097
Vance SD, Panning MP, Staehler S, et al., 2018, Geophysical Investigations of Habitability in Ice-Covered Ocean Worlds, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 123, Pages: 180-205, ISSN: 2169-9097
Vance SD, Kedar S, Panning MP, et al., 2018, Vital Signs: Seismology of Icy Ocean Worlds, ASTROBIOLOGY, Vol: 18, Pages: 37-53, ISSN: 1531-1074
Mimoun D, Murdoch N, Lognonne P, et al., 2017, The Noise Model of the SEIS Seismometer of the InSight Mission to Mars, SPACE SCIENCE REVIEWS, Vol: 211, Pages: 383-428, ISSN: 0038-6308
Teanby NA, Stevanovic J, Wookey J, et al., 2017, Seismic Coupling of Short-Period Wind Noise Through Mars' Regolith for NASA's InSight Lander, SPACE SCIENCE REVIEWS, Vol: 211, Pages: 485-500, ISSN: 0038-6308
Stott AE, Kanna S, Mandic DP, et al., 2017, AN ONLINE NIPALS ALGORITHM FOR PARTIAL LEAST SQUARES, IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), Publisher: IEEE, Pages: 4177-4181, ISSN: 1520-6149
Pike WT, Slingsby-Smith Z, McClean J, 2017, Solar System Geophysics with the Silicon Seismic Package: From Earth to Europa, Planetary Science Vision 2050 Workshop
Golombek M, Kipp D, Warner N, et al., 2016, Selection of the InSight Landing Site, Space Science Reviews, Vol: 211, Pages: 5-95, ISSN: 0038-6308
The selection of the Discovery Program InSight landing site took over four years from initial identification of possible areas that met engineering constraints, to downselection via targeted data from orbiters (especially Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) and High-Resolution Imaging Science Experiment (HiRISE) images), to selection and certification via sophisticated entry, descent and landing (EDL) simulations. Constraints on elevation ( ≤−2.5 km≤−2.5 km for sufficient atmosphere to slow the lander), latitude (initially 15°S–5°N and later 3°N–5°N for solar power and thermal management of the spacecraft), ellipse size (130 km by 27 km from ballistic entry and descent), and a load bearing surface without thick deposits of dust, severely limited acceptable areas to western Elysium Planitia. Within this area, 16 prospective ellipses were identified, which lie ∼600 km north of the Mars Science Laboratory (MSL) rover. Mapping of terrains in rapidly acquired CTX images identified especially benign smooth terrain and led to the downselection to four northern ellipses. Acquisition of nearly continuous HiRISE, additional Thermal Emission Imaging System (THEMIS), and High Resolution Stereo Camera (HRSC) images, along with radar data confirmed that ellipse E9 met all landing site constraints: with slopes <15° at 84 m and 2 m length scales for radar tracking and touchdown stability, low rock abundance (<10 %) to avoid impact and spacecraft tip over, instrument deployment constraints, which included identical slope and rock abundance constraints, a radar reflective and load bearing surface, and a fragmented regolith ∼5 m thick for full penetration of the heat flow probe. Unlike other Mars landers, science objectives did not directly influence landing site selection.
Panning MP, Lognonné P, Bruce Banerdt W, et al., 2016, Planned Products of the Mars Structure Service for the InSight Mission to Mars, Space Science Reviews, Vol: 211, Pages: 611-650, ISSN: 0038-6308
The InSight lander will deliver geophysical instruments to Mars in 2018, including seismometers installed directly on the surface (Seismic Experiment for Interior Structure, SEIS). Routine operations will be split into two services, the Mars Structure Service (MSS) and Marsquake Service (MQS), which will be responsible, respectively, for defining the structure models and seismicity catalogs from the mission. The MSS will deliver a series of products before the landing, during the operations, and finally to the Planetary Data System (PDS) archive. Prior to the mission, we assembled a suite of a priori models of Mars, based on estimates of bulk composition and thermal profiles. Initial models during the mission will rely on modeling surface waves and impact-generated body waves independent of prior knowledge of structure. Later modeling will include simultaneous inversion of seismic observations for source and structural parameters. We use Bayesian inversion techniques to obtain robust probability distribution functions of interior structure parameters. Shallow structure will be characterized using the hammering of the heatflow probe mole, as well as measurements of surface wave ellipticity. Crustal scale structure will be constrained by measurements of receiver function and broadband Rayleigh wave ellipticity measurements. Core interacting body wave phases should be observable above modeled martian noise levels, allowing us to constrain deep structure. Normal modes of Mars should also be observable and can be used to estimate the globally averaged 1D structure, while combination with results from the InSight radio science mission and orbital observations will allow for constraint of deeper structure.
Liu H, Pike WT, 2016, A micromachined angular-acceleration sensor for geophysical applications, Applied Physics Letters, Vol: 109, ISSN: 1077-3118
This paper presents an angular-acceleration sensor that works as either an angular accelerometer or a gravity gradiometer and is based on the micro electromechanical system (MEMS) technology. The changes in the angle of the sensor mass are sensed by a rotational capacitive array transducer that is formed by electrodes on both the stator and rotor dies of the flip-chip-bonded MEMS chip (21 mm × 12.5 mm × 1 mm). The prototype was characterized, demonstrating a fundamental frequency of 27 Hz, a quality factor of 230 in air, and a sensitivity of 6 mV/(rad/s2). The demonstrated noise floor was less than 0.003 rad/s2/Hz−−−√Hz within a bandwidth of 0.1 Hz to 10 Hz, which is comparable with the conventional angular accelerometer and is better than the other reported MEMS sensors in low-frequency ranges. The features of small size and low cost suggest that this MEMS angular-acceleration sensor could be mounted on a drone, a satellite or even a Mars rover, and it is promising to be used for monitoring angular accelerations, aiding seismic recording, mapping gravity anomalies, and other geophysical applications for large-scale terrestrial and space deployments.
Liu H, Pike WT, Dou G, 2016, A seesaw-lever force-balancing suspension design for space and terrestrial gravity-gradient sensing, Journal of Applied Physics, Vol: 119, Pages: 124508-1-124508-10, ISSN: 0021-8979
We present the design, fabrication, and characterization of a seesaw-lever force-balancing suspension for a silicon gravity-gradient sensor, a gravity gradiometer, that is capable of operation over a range of gravity from 0 to 1 g. This allows for both air and space deployment after ground validation. An overall rationale for designing a microelectromechanical systems(MEMS) gravity gradiometer is developed, indicating that a gravity gradiometer based on a torsion-balance, rather than a differential-accelerometer, provides the best approach. The fundamental micromachined element, a seesaw-lever force-balancing suspension, is designed with a low fundamental frequency for in-plane rotation to response gravity gradient but with good rejection of all cross-axis modes. During operation under 1 g, a gravitational force is axially loaded on two straight-beams that perform as a stiff fulcrum for the mass-connection lever without affecting sensitive in-plane rotational sensing. The dynamics of this suspension are analysed by both closed-form and finite element analysis, with good agreement between the two. The suspension has been fabricated using through-wafer deep reactive-ion etching and the dynamics verified both in air and vacuum. The sensitivity of a gravity gradiometer built around this suspension will be dominated by thermal noise, contributing in this case a noise floor of around 10 E/Hz−−−√10 E/Hz (1 E = 10−9/s2) in vacuum. Compared with previous conventional gravity gradiometers, this suspension allows a gradiometer of performance within an order of magnitude but greatly reduced volume and weight. Compared with previous MEMS gravity gradiometers, our design has the advantage of functionality under Earth gravity.
Otter W, Hu F, Hanham S, et al., 2016, Terahertz metamaterial devices, International Conference on Semiconductor Mid-IR and THz Materials and Optics (SMMO2016)
Lognonné P, Pike WT, 2015, Planetary seismometry, Extraterrestrial Seismology, Pages: 36-50, ISBN: 9781107041721
The technical challenges of planetary seismometry Basics of seismometry Seismology is based on the recording, analysis, and inversion of seismic waves. It therefore requires appropriate instrumentation to measure these waves. Although first proposed and attempted in the early days of space exploration with the Ranger program (see Section 3.2.1), it was not until July 1969 that the first successful measurements were made in planetary exploration, with the installation of the Apollo 11 seismometer (Figure 3.1). This instrument, like all seismometers, is an inertial system detecting the ground acceleration generated by the seismic waves. Strictly speaking, these inertial systems are not only detecting the ground acceleration, but the sum of all temporal changes of the gravity, which include those related to the ground relative acceleration plus the local gravity change due to the displacement of the sensor (horizontal tilt and free air anomaly) and the gravitational change due to global mass redistribution generated by the seismic event and associated waves. To achieve the detection of inertial acceleration, most seismic instruments measure the motion of a mass suspended by a spring with either velocity transducers based on a coil/magnet system generating a voltage, for example in geophones, or with a displacement transducer based on capacitive or linear variable differential transformer outputs, as used in modern seismometers. Ground acceleration or velocity is then recovered through the instrument transfer function. Instrumental noise limitations The smallest seismic signal that can be detected by a seismometer is determined by the ability to resolve it above the aseismic background, which will inevitably also contribute to the recorded data. The lower this background, the better the performance of the instrument. This background, most often called the instrumental noise, can be divided into two contributions: the inherent noise generated by the instrument in the abs
Liu H, Pike WT, 2015, A SILICON/SOLDER BILAYER THERMAL ACTUATOR FOR COMPENSATING THERMAL DRIFT OF SILICON SUSPENSIONS, 18th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS), Publisher: IEEE, Pages: 916-919
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- Citations: 5
Delahunty AK, Pike WT, 2014, Metal-armouring for shock protection of MEMS, Sensors and Actuators A: Physical, Vol: 215, Pages: 36-43, ISSN: 0924-4247
This paper demonstrates a novel concept for the shock protection of MEMS suspensions: solder is incorporated within the sidewalls of the suspension to produce protective metal armouring. This provides solder–solder contact at the extremes of the suspension travel, greatly increasing the shock resistance. Model suspension systems were fabricated using deep reactive ion etching (DRIE) and shock tested in a drop-test rig at acceleration levels up to 6000 × g. The solder armour proved to absorb ∼90% of the collision kinetic energy and double the shock resistance of the MEMS suspension.
Liu H, Pike WT, Dou G, 2014, Design, Fabrication and Characterization of a Micro-Machined Gravity Gradiometer Suspension, 13th IEEE Sensors Conference, Publisher: IEEE, Pages: 1611-1614, ISSN: 1930-0395
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- Citations: 5
Pike WT, Delahunty AK, Mukherjee A, et al., 2014, A self-levelling nano-g silicon seismometer, 13th IEEE Sensors Conference, Publisher: IEEE, Pages: 1599-1602, ISSN: 1930-0395
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- Citations: 19
Pike WT, Standley IM, Calcutt S, 2013, A silicon microseismometer for Mars, Pages: 622-625
The design, fabrication and testing of a microseismometer for the InSight mission to Mars and described. Particular challenges include accommodation of Martian gravity while allowing testing on Earth and surviving the 2000g shock profile of the mission while maintaining a nano-g sensitivity. © 2013 IEEE.
Claus D, Robinson DJ, Chetwynd DG, et al., 2013, Dual wavelength optical metrology using ptychography, JOURNAL OF OPTICS, Vol: 15, ISSN: 2040-8978
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- Citations: 29
Delahunty A, Pike WT, 2013, INTEGRATING SOLDER BUMPERS FOR HIGH SHOCK APPLICATIONS, 26th IEEE International Conference on Micro Electro Mechanical Systems (MEMS), Publisher: IEEE, Pages: 689-692, ISSN: 1084-6999
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- Citations: 2
Goetz W, Hecht MH, Hviid SF, et al., 2012, Search for ultraviolet luminescence of soil particles at the Phoenix landing site, Mars, PLANETARY AND SPACE SCIENCE, Vol: 70, Pages: 134-147, ISSN: 0032-0633
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- Citations: 7
Forrest AL, Wittmann ME, Schmidt V, et al., 2012, Quantitative assessment of invasive species in lacustrine environments through benthic imagery analysis, Limnology and Oceanography: Methods, Vol: 10, Pages: 65-74
The establishment, spread, and impact of the invasive bivalve Corbicula fluminea (C. fluminea), in Lake Tahoe threatens native species distribution in the lake and, potentially, has long-term implications for water clarity. In 2009, UBC-Gavia, an Autonomous Underwater Vehicle (AUV), was used as a platform to collect georeferenced imagery of the benthic regions of Lake Tahoe to determine the lake-wide distribution of C. fluminea. Images were collected in water depths less than 10 m at an approximately constant height above the bottom of 2 m. Images were processed using a semi-automated procedure to determine the ratio of the lakebed covered by exposed C. fluminea shells. A visual review was conducted on a subset of the images to determine presence of filamentous algae that has been observed in association with C. fluminea. Nearly 100km of shoreline was covered over a 7-d period, and C. fluminea presence was reconfirmed in 4 regions and additional 10 regions identified. In regions where the presence of C. fluminea was confirmed, C. fluminea depth distribution was validated by comparing image detection counts and results from a benthic sediment grab sample survey. Three regions around the lake were identified to have filamentous green algae or charophyte species. It was impossible to identify species of the known filamentous algal taxa (Cladophora glomerata, Spirogyra spp., and Zygnema spp.). The collected imagery provides a synoptic view on species distribution within the lake that can be used for efficient monitoring of invasive species in freshwater and saltwater bodies. © 2012, by the American Society of Limnology and Oceanography, Inc.
Koellensperger PA, Karl WJ, Ahmad MM, et al., 2012, Patterning of platinum (Pt) thin films by chemical wet etching in Aqua Regia, JOURNAL OF MICROMECHANICS AND MICROENGINEERING, Vol: 22, ISSN: 0960-1317
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- Citations: 24
Smith A, Crawford IA, Gowen RA, et al., 2012, Lunar Net-a proposal in response to an ESA M3 call in 2010 for a medium sized mission, EXPERIMENTAL ASTRONOMY, Vol: 33, Pages: 587-644, ISSN: 0922-6435
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- Citations: 15
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