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Thermogravimetry: a technique for planetary in-situ missions

IMM Roma. Thermogravimetry: a technique for planetary in-situ missions. A. Longobardo 1 ,F. Dirri 2 , E. Palomba 1 , A. Zinzi 3 , E. Zampetti 4 , S. Pantalei 4 , D. Biondi 1 , B. Saggin 5 , A.Bearzotti 4 and A. Macagnano 4 1 IAPS-INAF, Via Fosso del Cavaliere 100, 00133 Rome, Italy

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Thermogravimetry: a technique for planetary in-situ missions

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  1. IMM Roma Thermogravimetry: a technique for planetary in-situ missions A. Longobardo1,F. Dirri2, E. Palomba1, A. Zinzi3, E. Zampetti4, S. Pantalei4,D. Biondi1, B. Saggin5, A.Bearzotti4 and A. Macagnano4 1IAPS-INAF, Via Fosso del Cavaliere 100, 00133 Rome, Italy 2Dipartimento di Fisica, Università La Sapienza, Rome, Italy 3DISAM, Università Parthenope, Naples, Italy 4IMM-CNR, Rome, Italy 5Politecnico di Milano, Milan, Italy

  2. IMM Roma Outline • Introduction to Thermogravimetry • Planetary applications • The VISTA project • Laboratory measurements • Conclusions EPSC 2012, Madrid

  3. Basic principles IMM Roma Thermogravimetry is a widely used technique to study absorption, sublimation and condensation processes. The instrument core is a Piezoelectric Crystal Microbalance (PCM), whose oscillation frequency increases at decreasing deposited mass: once the material is deposited onto the sensor it is possible to measure the amount of weight change as a function of increasing temperature due to the release of more volatile species. The temperature is increased by an appropriate heater. Abundance volatile compound Composition volatile compound EPSC 2012, Madrid

  4. Application fields Detection and analysis of volatiles compounds in the studied samples, i.e. adsorbed/included in the molecular structure, or in the studied environment Analysis of condensable species, i.e. discrimination between different phases (gas/liquid/solid). The Thermo-Gravimetric Analysis (TGA) can be performed in two temperature regimes, depending on the purpose: ACT (Ambient to Cryogenic Temperatures Regime): <300 K AHT (Ambient to High Temperatures Regime): >300 K IMM Roma EPSC 2012, Madrid

  5. IMM Roma Techniques for volatile measurements • Attenuated Total Reflectance (ATR) - mass not lower than 200 g - power of few watts required • Gas Cromatography/Mass Spectroscopy (GC-MS) / mGC-MS - instrument size of cm3 - problems about interface between GC and MS • ThermoGravimetric Analysis (TGA) / mTGA - low mass (25 g) - low size (cm3) - low requested power (<1 W) EPSC 2012, Madrid

  6. IMM Roma Outline • Introduction to Thermogravimetry • Planetary applications • The VISTA project • Laboratory measurements • Conclusions EPSC 2012, Madrid

  7. Moon Scientific goals in a lunar lander scenario • Water ice detection • Measurement of water, organics and other volatiles content in the lunar regolith • Analysis of electrical properties of regolith EPSC 2012, Madrid

  8. Asteroids and comets Scientific goals in a in-situ mission on asteroids or comets • Measurement of water and organic content in the asteroid regolith (asteroid taxonomy) • Detection of cometary activity (measuring flux and dust/ice ratio) EPSC 2012, Madrid

  9. Icy satellites Scientific goals in a in-situ mission on a icy satellite (e.g. Europa and Ganimede) • Discrimination between water ice and clathate hydrates (not possible by means of spectral analysis) • Determination of non-ice materials composition (solphates, carbonates, H2O2), characterised by different sublimation temperatures • Detection of possible organic presence EPSC 2012, Madrid

  10. Mars Scientific goals in a martian lander scenario • Measurement of water frost point, i.e. relative humidity • Detection of possible ice falls • Measurement of dust settling rate • Measurement of water, organics and carbonates content in the Martian dust (related to habitability of the planet) EPSC 2012, Madrid

  11. Venus Scientific goals in a aerostatic balloon mission on Venus • Dew point (i.e. partial pressure) measurement of cloud condensable species • Discrimination of volatile and refractory species in aerosols • Analysis of areosol electrical properties EPSC 2012, Madrid

  12. Titan Scientific goals in a aerostatic balloon mission on Titan • Measurement of methan dew point (i.e. mixing ratio) • Measurement of organics content (e.g. ethane, acetylene, benzene) in cloud aerosols (possible thanks to their different volatility and partial pressure) EPSC 2012, Madrid

  13. IMM Roma Outline • Introduction to Thermogravimetry • Planetary applications • The VISTA project • Laboratory measurements • Conclusions EPSC 2012, Madrid

  14. IMM Roma Volatile In-Situ Thermogravimetry Analyser VISTA is the thermogravimeter developed by a consortium of Italian institutes, led by IAPS-INAF and coordinated by Dr. Ernesto Palomba. • Light (25 grams) • Small (2x2x3 cm3) • Lowpower-consuming • (60 mW for DT=60° K • in vacuum) • High sensitivity • (10-100 ppm) EPSC 2012, Madrid

  15. Instrument concept IMM Roma VISTA has a heater and a thermistor integrated onto the crystal. The thermistor can act as additional heater, in parallel to the other heater. In this configuration the required voltage to obtain a certain DT decreases of 50%. Simulation: V=1 V, I=50 mA P=50 mW in air EPSC 2012, Madrid

  16. IMM Roma The lunar version: MOVIDAMOon Volatile, Ice and Dust Analyser The microbalance is placed inside a capacitor held at a voltage DV. Dust particles passing through the capacitor will deposit on the PCM in a time t depending on their charge-to-mass ratio q/m: q/m= 2/(DV t2) Legend Lunar surface Capacitor Microbalance Dust particle EPSC 2012, Madrid

  17. IMM Roma VISTA and ESA Cosmic Vision Different VISTA configurations have been studied for Phase A of the following ESA Cosmic Vision (2015-2025) missions: MARCO POLO Target: primitive asteroid MARCOPOLO-R Target: primitive asteroid Penetrator for EJSM Target: Europa and Ganimede EPSC 2012, Madrid

  18. IMM Roma Outline • Introduction to Thermogravimetry • Planetary applications • The VISTA project • Laboratory measurements • Conclusions EPSC 2012, Madrid

  19. Water desorption from clay (1) IMM Roma Controlled hydration camera The mass of a clay sample has been measured • Before the controlled hydration • After the controlled hydration • After the mTGA In the two performed tests, the TGA measures show a very good agreeement between the amount of water absorbed from clay during its hydration and the amount of released water after the heating (Zinzi et al., Sensor and Actuators A, 2011). EPSC 2012, Madrid

  20. Water desorption from clay (2) IMM Roma Three kinds of experiments performed, differing on humid flux exposure time Images from Zinzi et al., Sensor and Actuators A, 2011 No dependence on exposure time EPSC 2012, Madrid

  21. IMM Roma Enthalpy of sublimation of adipic acid in vacuum (1) Adipic acid has been heated at different temperatures and hence deposited on a cold PCM (TPCM = -25°C) EPSC 2012, Madrid

  22. IMM Roma Enthalpy of sublimation of adipic acid in vacuum (1) Adipic acid has been heated at different temperatures and hence deposited on a cold PCM (TPCM = -25°C) Becker containingadipic acid Copper shield Plate PCM EPSC 2012, Madrid

  23. IMM Roma Enthalpy of sublimation of adipic acid in vacuum (2) Deposition rates of adipic acid at different temperatures have been measured. Enthalpy of sublimation has been inferred by Van’t Hoff relation: DH : enthaply of sublimation T1and T2 : adipic acid temperatures R1and R2 : deposition rates at temperatures T1and T2 R: gas constant We found DH = 131 kJ/mol, in agreement with the literature value (129.3±2.5) kJ/mol EPSC 2012, Madrid

  24. IMM Roma Outline • Introduction to Thermogravimetry • Planetary applications • The VISTA project • Laboratory measurements • Conclusions EPSC 2012, Madrid

  25. IMM Roma Conclusions • Thermogravimetry can find application in many planetary environments • An instrument based on TGA (i.e. VISTA) is under study and development for space applications: it is very light, small and low-power consuming • A VISTA laboratory breadboard has been tested by performing measurements of water desorption and enthalpy of sublimation EPSC 2012, Madrid

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