| 211. |
- Soria-Salinas, Álvaro, et al.
(författare)
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Development of a wind retrieval method for low-speed low-pressure flows for ExoMars
- 2020
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Ingår i: Applied Thermal Engineering. - : Elsevier. - 1359-4311 .- 1873-5606. ; 180
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Tidskriftsartikel (refereegranskat)abstract
- Forced convective heat transfer from three horizontally inclined rectangular-based cylinders (rods) has been studied experimentally under representative Martian near-surface air flows in the Aarhus Wind Tunnel Simulator (AWTS), Denmark. The testing campaign was developed for the HABIT (Habitability: Brines, Irradiation and Temperature) instrument, European payload on board the ExoMars 2022 Kazachok surface platform. The average heat transfer coefficient was determined from steady CO2 flows at a pressure of 9.9 mbar, an ambient temperature of ∼25 °C, and for horizontal free-stream velocities between 0.8 and 12 m/s. A retrieval algorithm to derive the wind speed from the average heat transfer coefficient estimated at each of the three HABIT Air Temperature Sensors (ATS) rods was calibrated within the AWTS. The ATS rods are placed one at the front of the instrument structure (ATS2) and two on the sides (ATS1 and ATS3); and under Martian atmospheric conditions these rods serve as cooling fins. Several relationships between the Nusselt number and the Reynolds and Prandtl numbers reported in the literature were evaluated to model convective heat transfer from the ATS rods. Where needed, corrections to account for radiative heat transfer within the AWTS were implemented. The final retrieval method demonstrated that wind speed can be retrieved for frontal winds in the range of 0–10 m/s, with an error of ±0.3 m/s, using the cooling profile of the ATS rod 3, and for lateral winds in the range of 0–6 m/s, with an error of ±0.3 m/s, using the ATS rod 2 cooling profile.
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| 212. |
- Soria-Salinas, Álvaro
(författare)
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Development of the Wind and Air Temperature Sensor of the ExoMars 2022 HABIT Instrument
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This work presents the development, validation and calibration of the air temperature sensors (ATS) and the air and wind retrieval method of the HABIT (HabitAbility: Brines, Irradiation and Temperature) instrument. HABIT is one of the two European payloads of the ESA/Roscosmos ExoMars 2022 mission that will land at Oxia Planum (18.20° N, 335.45° E), on Mars.One of the main novelties of this Ph.D. thesis is to use the thin fins that work as ATS on HABIT as a wind sensor for the planetary boundary layer of Mars. The thesis is based on the study and modelling of heat transfer along three rods when exposed to forced convection in a gaseous fluid, and that is tested: (1) through computational fluid dynamic simulations, which provided inputs to the early design of the HABIT structure; (2) under laboratory conditions, with the use of a specifically designed prototype and a cooling fan; and (3) within a subsonic wind tunnel facility under terrestrial conditions.A preliminary validation of the wind speed retrieval approach is first performed using temperature measurements from Mars provided by the Rover Environmental Monitoring Station (REMS) instrument, on board the NASA Curiosity rover of the Mars Science Laboratory (MSL) mission. The method is based on modelling forced convection of the ATS of REMS when assumed as thin rods immersed in the extreme low-pressure and high-radiating atmospheric conditions of the Martian thermal boundary layer, at a height of ∼ 1.5 m from the surface. Assuming the previously reported REMS wind sensor (WS) retrieval errors of 20% for the wind speed, ±30° for the horizontal “front” wind directions, and ±45° for the horizontal “rear” wind directions, agreement with the WS values of up to 77% of the acquisition time, on average, for wind speeds and coincidence between 60% and 80% of the time for wind directions is reported for some sols. These promising results are limited to only evening extended acquisitions from 18:00 to 21:00 local mean solar time (LMST) and orientations within the validity region of the retrieval. That is, the method was only considered valid over a narrow angle range of 13° to 107° in azimuth angle. In addition to this, the results of this first study suggested a new optimal orientation when using the ATS for wind speed and direction retrievals of +60° clockwise with respect to the forward direction of the Curiosity rover.The wind retrieval model is also validated and calibrated with the HABIT engineering and qualification model (EQM) in the Aarhus Wind Tunnel Simulator (AWTS) of the Aarhus University, Denmark. The AWTS is designed to reproduce typical winds on the surface of Mars. The data acquired during the wind tunnel campaign were used to validate the forced convective and radiative heat transfer model for each of the three ATS. The campaign investigated winds in steady CO2 flows at a pressure of 9.9 mbar, an ambient temperature of 25°C, and for horizontal free-stream velocities between 0.8 and 12 m/s. Several relationships between the Nusselt number and the Reynolds and Prandtl numbers reported in the literature were evaluated in the tunnel to model forced convection through the ATS rods. Where needed, corrections to account for radiative heat transfer within the AWTS were implemented to correct for experimental artefacts. The tests demonstrated that this retrieval method can be used to derive wind speed for frontal winds on Mars in the range of 0 to 10 m/s, with an error of ±0.3 m/s, using the cooling profile of the ATS rod 3, and for lateral winds in the range of 0 to 6 m/s, with an error of ±0.3 m/s, using the ATS rod 2 cooling profile.The thesis also includes the calibration of the HABIT ATS flight model (FM) in the clean room of Omnisys Instruments AB, and the retrieval model that will be used in operations during the ExoMars 2022 mission and for archiving in the Planetary Science Archive (PSA) of the European Space Agency (ESA).Finally, the wind retrieval method developed in this thesis can be applied not only to the future analysis of HABIT data at Oxia Planum, but also to re-analyse the ATS data of REMS at Gale crater, and for future comparative analysis with the HABIT/ExoMars 2022, the Temperature and Wind Sensors for InSight (TWINS)/InSight, and the Mars Environmental Dynamics Analyzer (MEDA)/Mars 2020 rover instruments.
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| 213. |
- Soria-Salinas, Álvaro, et al.
(författare)
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Microgravity validation for xenon propellant distributions
- 2017
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Konferensbidrag (refereegranskat)abstract
- In the current Electric Propulsion era, one of the most relevant propellants is xenon, which is generally stored in supercritical stage. Because of the increase in time of spacecraft lifetime, the amount of propellant stored on-board has been quadrupled in the recent years, and the need of more accurate gauging methods for measuring propellant usage along the missions has become more critical too. Thermal gradients affect the densities distribution of the stored propellants and this turns out to be critical in orbit because of the absence of convection in low-gravity environments. Recently we have proposed a new gauging method (Soria-Salinas, et al., 2017) that relies on the analysis of measurements from existing and operating technology (in TRL 9), i.e., this method does not imply the development of any new technology. This new method, the improved PVT method, improves by a factor 8 the accuracy of the standard PVT retrievals (Soria-Salinas, et al., 2017). A laboratory experimental validation has shown that, for CO2 at a pressure of about 70 bar, just below the critical pressure, the error of the mass retrieval using this new gauging method is only 0.1% of the initial mass at launch. However, for its complete validation, a microgravity study should be performed in order to quantify the effect of thermal gradients under the absence of convection in a low-g environment. The present work describes: 1) the design of a proposed in-flight microgravity validation experiment for a parabolic flight campaign such as those provided by the Airbus A-310 zero-G platform for microgravity research; and 2) comparative studies of the expected xenon density distribution of real size tanks under operation in orbit, through computational fluid dynamics (CFD) and heat transfer calculations.
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| 214. |
- Soria Salinas, Álvaro Tomás, et al.
(författare)
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Improved Pressure-Volume-Temperature Gauging Method for Electric Propulsion Systems (PVT-GAMERS) : flight-model experiment for zero-g validation.
- 2018
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Ingår i: IAC-18. - : International Astronautical Federation.
-
Konferensbidrag (refereegranskat)abstract
- Current forecasts suggest that, by 2030, at least 50% of telecommunication satellites will use electric propulsion (EP) as the only propulsion system on board. The ever-increasing operations time has led to a substantial increment of the amount of propellant stored on-board, from the initial 200-350 kg to present-day masses of 800-1500 kg. Despite the need to know the available propellant mass during operations, the retrieval is still challenging, and inaccurate, as no technological alternatives have been proven to satisfy with the needed requirements for long duration missions.Recently we have proposed a new gauging method that uses TLR-9 hardware components. The method, called Improved-PVT method, is based on a better understanding of the thermal properties of the stored xenon. Laboratory experiments and theoretical work demonstrated an accuracy improved by a factor of 8 compared to classical Pressure-Volume-Temperature retrievals [A. Soria-Salinas et al., 2017]. In fact, it gives an error of mass gauging of 0.1% with respect to the initial mass, at a pressure of about 70 bar.This method has been implemented in the PVT-GAMERS experiment, selected to fly at the ESA Fly Your Thesis! parabolic flight campaign, between October 22 nd to November 2 nd . As a technology demonstrator, it consists of a suit of 6 small-scaled and pressurized CO2 tanks, sensed with pressure (P) and temperature (T) sensors, with a heating duty cycle and real-time data processing. The PVT-GAMERS experiment will fly on three Airbus A310 Zero-G flights, where micro/hyper gravity-loads will allow to demonstrate the robustness of the method against thermal gradients, and i) simulated thruster ignitions, ii) external accelerations and iii) propellant management operations scenarios. These flights will also increase the TRL of the full system from 4 to 6.In this work, we shall present the development, testing and ground calibration of the PVT-GAMERS experiment, including: 1) ground tests, assembly validation, expected results and operational procedures estimation; and 2) calibration of mass retrieval algorithm applied over a CO2 PVT-GAMERS engineering model (EM). Ground tests results indicates a relative error expected for the mass retrieval on flight model ground tests < 1.4% for CO2 gas at EOL conditions. Furthermore, a compromised solution shall be reached between retrieval expected accuracy, cooling rate for the retrieval application, and sensitivity to ambient condition changes. The EM tests suggest on this particular configuration to approximate the cooling ratio dP/dT using a least-squared-error procedure and over an interval of at least 900 seconds.
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| 215. |
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| 216. |
- Soria-Salinas, Álvaro, et al.
(författare)
-
Wind retrieval from temperature measurements from the Rover Environmental Monitoring Station/Mars Science Laboratory
- 2020
-
Ingår i: Icarus. - : Elsevier. - 0019-1035 .- 1090-2643. ; 346
-
Tidskriftsartikel (refereegranskat)abstract
- This work presents a novel method for the real-time retrieval of wind speed on the surface of Mars that uses temperature measurements from the Rover Environmental Monitoring Station (REMS) instrument onboard the Curiosity rover of the Mars Science Laboratory (MSL) mission. After final failure of the Wind Sensor (WS) in sol 1491, REMS has not been providing wind data. The new wind retrieval approach that we propose may eventually be able to supply MSL with wind values for contextualizing the roverâôs operations and for meteorological studies on the surface of Mars. The new method is based on forced convection modeling of the Air Temperature Sensors (ATS) of REMS as thin rods immersed in the extreme low-pressure and high-radiating atmospheric conditions of the Martian thermal boundary layer at a height of ∼" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 16.2px; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;">∼ 1.5 m from the surface. A preliminary validation of the possibilities and limitations of this retrieval has been performed using comparative analysis with existing REMS wind field-site data for the same sols that are available at the Planetary Data System (PDS). We have developed both a ”coarse” approach, in which wind speed is determined with no regard to wind direction, and a ”refined” method, in which it is attempted to determine both wind speed and direction. Assuming the previously reported WS retrieval errors of 20% for the wind speed, we report an agreement to the WS values of wind speed ranging from 36.4% to 77% of the acquisition time for the ”coarse” approach, depending on the sol examined. These promising results are limited to only evening extended acquisitions from 18:00 to 21:00 local mean solar time (LMST). This method could be applied to daytime conditions. The results suggest a new optimal orientation for wind speed retrieval of 60°clockwise with respect to the forward direction of the Curiosity rover, although the technique is not yet ready to be considered for planning of the Curiosity rover operations. This method could extend the wind characterization of the Gale Crater for future Curiosity rover data acquisitions by recycling air temperature measurements and provide the scientific community with a data set for future comparative analysis with the Temperature and Wind Sensors for InSight (TWINS)/InSight, the HabitAbility: Brines, Irradiation and Temperature (HABIT)/ExoMars 2020, and the Mars Environmental Dynamics Analyzer (MEDA)/Mars 2020 rover instruments.
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| 217. |
- Soria-Salinas, Álvaro, et al.
(författare)
-
Wind Retrieval Measurements for the Mars Surface Exploration
- 2016
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We present a novel method to quantify the heat transfer coefficient h at the near environment of a spacecraft operating under Mars surface atmospheric conditions. As part of the scientific instruments of the ExoMars 2018 Surface Platform, the HABIT (HabitAbility: Brines, Irradiance and Temperature) instrument will be operating on Mars surface in order to establish the habitability of the landing site. By resolving the energy balance equation in temperatures over the three HABIT Air Temperature Sensor (ATS), we will retrieve the fluid temperature Tf and the known as m-parameter directly related with the heat transfer coefficient and sensitive to variations in wind density and velocity field
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| 218. |
- Stern, Jennifer C., et al.
(författare)
-
Evidence for indigenous nitrogen in sedimentary and aeolian deposits from the Curiosity rover investigations at Gale crater, Mars
- 2015
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 112:14, s. 4245-4250
-
Tidskriftsartikel (refereegranskat)abstract
- The Sample Analysis at Mars (SAM) investigation on the Mars Science Laboratory (MSL) Curiosity rover has detected oxidized nitrogen-bearing compounds during pyrolysis of scooped aeolian sediments and drilled sedimentary deposits within Gale crater. Total N concentrations ranged from 20 to 250 nmol N per sample. After subtraction of known N sources in SAM, our results support the equivalent of 110–300 ppm of nitrate in the Rocknest (RN) aeolian samples, and 70–260 and 330–1,100 ppm nitrate in John Klein (JK) and Cumberland (CB) mudstone deposits, respectively. Discovery of indigenous martian nitrogen in Mars surface materials has important implications for habitability and, specifically, for the potential evolution of a nitrogen cycle at some point in martian history. The detection of nitrate in both wind-drifted fines (RN) and in mudstone (JK, CB) is likely a result of N2 fixation to nitrate generated by thermal shock from impact or volcanic plume lightning on ancient Mars. Fixed nitrogen could have facilitated the development of a primitive nitrogen cycle on the surface of ancient Mars, potentially providing a biochemically accessible source of nitrogen.
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| 219. |
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| 220. |
- Stolper, E.M., et al.
(författare)
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The petrochemistry of Jake_M : A martian mugearite
- 2013
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 341:6153
-
Tidskriftsartikel (refereegranskat)abstract
- “Jake_M,” the first rock analyzed by the Alpha Particle X-ray Spectrometer instrument on the Curiosity rover, differs substantially in chemical composition from other known martian igneous rocks: It is alkaline (>15% normative nepheline) and relatively fractionated. Jake_M is compositionally similar to terrestrial mugearites, a rock type typically found at ocean islands and continental rifts. By analogy with these comparable terrestrial rocks, Jake_M could have been produced by extensive fractional crystallization of a primary alkaline or transitional magma at elevated pressure, with or without elevated water contents. The discovery of Jake_M suggests that alkaline magmas may be more abundant on Mars than on Earth and that Curiosity could encounter even more fractionated alkaline rocks (for example, phonolites and trachytes).
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