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Link to old DSLP web page.
RSSD ESTEC/ESA: Jean-Pierre Lebreton (Co-I)
Czech Space Research Centre: Zdeněk Kozáček, Jan Břínek
The Dual Segmented Langmuir Probe (DSLP) is one of the four scientific experiments on board the ESA micro-satellite Proba 2
. The DSLP instrument has been developed and manufactured in close collaboration with the Czech Space Research Centre (Brno, Czech Republic) and the Research and Scientific Support Department of ESTEC/ESA (Noordwijk, Holland) under support of the ESA PECS/PRODEX program. With TPMU experiment as a part of the Plasma Measurements Equipment, the DSLP instrument will aim at studying characteristic macroscopic properties (e.g. density, temperature or flow dynamics) of ionospheric plasmas and, with use of SWAP and LYRA observations, try to identify observed irregularities with possible solar-terrestrial connection related to sudden space weather events. A comprehensive knowledge of the ionospheric environment is important from many not solely scientific aspects. Intense solar events cause massive geomagnetic storms that represent possible risk of damage for communication and navigation satellite systems, ground electric grids and pipelines, or even radiation hazards for humans. Detail study of ionospheric processes and their space weather relations thus becomes an considerable issue in current space research activities.
Proba-2 Proba stands for PRoject for OnBoard Autonomy. The Proba satellites are among the smallest ever to be flown by ESA, but they are making a big impact in space technology. Proba-2 is the second of the series, building on nearly eight years of successful Proba-1 experience. Providing flight opportunities the Proba satellites are part of ESA’s In-orbit Technology Demonstration programme, missions dedicated to the demonstration of innovative technologies. In-orbit demonstration is the last step on the technology development ladder. New technology products need to be demonstrated in orbit, particularly when users require evidence of flight heritage or when there is a high risk associated with use of the new technology. Inorbit demonstration is achieved through experiments on carriers of opportunity, such as the International Space Station, or through dedicated small satellites such as the Proba series, which was created to increase the availability of flight-testing opportunities. Proba-2 is the result of ESA’s commitment to technological innovation. Altogether, 17 new technological developments for in-orbit demonstration are being flown on Proba-2 together with the main four scientific experiments.
Proba 2 was successfully launched on 2nd November 2009 as a co-passenger of the ESA Soil Moisture and Ocean Salinity (SMOS) mission. The mission life time is currently extended till the end of 2012.
Detail study of ionospheric environment is important from many not solely scientific aspects. First off all the ionosphere represents a great natural plasma laboratory - relatively easy to access for in-situ or ground-based remote sensing instrumentation. It would be worthless to emphasize the need of detail understanding of plasma environments which build up almost entire known matter in the universe. Especially the study of the Earth's ionosphere not only improve the knowledge of observed phenomena in the vicinity of the Earth itself but also help to understand similar phenomena observed in other ionospheres of many different solar system bodies (like giant planets and their moons). From practical point of view, the exact description of ionospheric conditions is necessary for all satellite telecommunications systems. The plasma environment not only strongly influence propagation of electro-magnetic (e.g. radio) waves but has also large impact on the satellites and their electronic sub-systems itself.
With the DSLP experiment we aim at identifying and studying characteristic macroscopic plasma properties (like density and temperature) at altitudes of about 700 km. Moreover, the novel concept of segmented probe will provide a diagnostic tool to study the dynamics (currents and flows) of ionospheric plasmas. Furthermore, with the benefit of SWAP and LYRA instruments on board Proba 2 we intend to examine possible solar-terrestrial connection related to observed space weather events such as CME’s, EIT waves, or solar flares. The technological part DSLP mission will aim to fully test the new capabilities of the SLP design and its applicability for future space scientific missions. The detail list of main DSLP scientific objectives follows:
The DSLP experiment represents a new type of a measuring device in the wide family of electrostatic Langmuir probes. The new technique used on this instrument consist in I-V characteristics acquisition from several independent sectors of a spherical shaped electrode. The probe will, therefore, provide measurements in situ directional diagnostics of surrounding plasma. This new concept, first tested on board French micro-satellite DEMETER, has been called the segmented Langmuir probe (SLP).
The new DSLP design for the Proba 2 mission is based on the SLP concept only and comprises two identical sensors. Both are spherical shaped probes divided into 7+1 independent segments (i.e., seven disc shaped segments on the sphere plus the rest of the conducting surface of the electrode). Both sensors of the DSLP experiment are mounted on the deployable back solar panel and the DSLP data processing unit (DPU) is accommodated inside the body of the Proba 2 satellite (see Figure 2). In addition to the classical measuring technique of electrostatic probes, the two identical SLP sensors of the DSLP instrument will be also tested as an electrical antenna. The E-field fluctuations can be sampled up to 2 MHz.
The DSLP instrument provides three measuring techniques:
Link to old DSLP web page.
Team
Pavel M. Trávníček (PI), Štěpán Štverák, David Herčík, Petr Hellinger, Ondřej Šebek, Roman PavelkaRSSD ESTEC/ESA: Jean-Pierre Lebreton (Co-I)
Czech Space Research Centre: Zdeněk Kozáček, Jan Břínek
DSLP on Proba 2
The Dual Segmented Langmuir Probe (DSLP) is one of the four scientific experiments on board the ESA micro-satellite Proba 2
. The DSLP instrument has been developed and manufactured in close collaboration with the Czech Space Research Centre (Brno, Czech Republic) and the Research and Scientific Support Department of ESTEC/ESA (Noordwijk, Holland) under support of the ESA PECS/PRODEX program. With TPMU experiment as a part of the Plasma Measurements Equipment, the DSLP instrument will aim at studying characteristic macroscopic properties (e.g. density, temperature or flow dynamics) of ionospheric plasmas and, with use of SWAP and LYRA observations, try to identify observed irregularities with possible solar-terrestrial connection related to sudden space weather events. A comprehensive knowledge of the ionospheric environment is important from many not solely scientific aspects. Intense solar events cause massive geomagnetic storms that represent possible risk of damage for communication and navigation satellite systems, ground electric grids and pipelines, or even radiation hazards for humans. Detail study of ionospheric processes and their space weather relations thus becomes an considerable issue in current space research activities.Proba-2 Proba stands for PRoject for OnBoard Autonomy. The Proba satellites are among the smallest ever to be flown by ESA, but they are making a big impact in space technology. Proba-2 is the second of the series, building on nearly eight years of successful Proba-1 experience. Providing flight opportunities the Proba satellites are part of ESA’s In-orbit Technology Demonstration programme, missions dedicated to the demonstration of innovative technologies. In-orbit demonstration is the last step on the technology development ladder. New technology products need to be demonstrated in orbit, particularly when users require evidence of flight heritage or when there is a high risk associated with use of the new technology. Inorbit demonstration is achieved through experiments on carriers of opportunity, such as the International Space Station, or through dedicated small satellites such as the Proba series, which was created to increase the availability of flight-testing opportunities. Proba-2 is the result of ESA’s commitment to technological innovation. Altogether, 17 new technological developments for in-orbit demonstration are being flown on Proba-2 together with the main four scientific experiments.
Proba 2 was successfully launched on 2nd November 2009 as a co-passenger of the ESA Soil Moisture and Ocean Salinity (SMOS) mission. The mission life time is currently extended till the end of 2012.
Scientific objectives
Detail study of ionospheric environment is important from many not solely scientific aspects. First off all the ionosphere represents a great natural plasma laboratory - relatively easy to access for in-situ or ground-based remote sensing instrumentation. It would be worthless to emphasize the need of detail understanding of plasma environments which build up almost entire known matter in the universe. Especially the study of the Earth's ionosphere not only improve the knowledge of observed phenomena in the vicinity of the Earth itself but also help to understand similar phenomena observed in other ionospheres of many different solar system bodies (like giant planets and their moons). From practical point of view, the exact description of ionospheric conditions is necessary for all satellite telecommunications systems. The plasma environment not only strongly influence propagation of electro-magnetic (e.g. radio) waves but has also large impact on the satellites and their electronic sub-systems itself.
With the DSLP experiment we aim at identifying and studying characteristic macroscopic plasma properties (like density and temperature) at altitudes of about 700 km. Moreover, the novel concept of segmented probe will provide a diagnostic tool to study the dynamics (currents and flows) of ionospheric plasmas. Furthermore, with the benefit of SWAP and LYRA instruments on board Proba 2 we intend to examine possible solar-terrestrial connection related to observed space weather events such as CME’s, EIT waves, or solar flares. The technological part DSLP mission will aim to fully test the new capabilities of the SLP design and its applicability for future space scientific missions. The detail list of main DSLP scientific objectives follows:
- Directional Measurements: Contrary to classical Langmuir probes, the new DSLP concept of data acquisition from the independent segments will enable to study also plasma characteristics in different directions. This should provide for example estimations of plasma flow velocity. Typically in the presence of magnetic field, electron temperatures are observed to be slightly different in the direction parallel and perpendicular to the magnetic field lines. This temperature anisotropy should be measured with DSLP by way of directional data acquisition.
- Non-Maxwellian Features in Ionospheric Plasma: Classical theories for LPs are typically developed for plasmas in a thermodynamic equilibrium, that is for particle populations possessing Maxwellian velocity distribution functions. However, a thermodynamic equilibrium and thus a Maxwellian distribution is an idealized case while the real distribution in many plasma environments often exhibits various non-Maxwellian features, like loss-cone or flat-top distributions or high-energy tails. We intend to adapt the DSLP theoretical model in order to see whether such features exist also in ionospheric plasmas.
- Ionospheric Irregularities: Ionosphere especially in the equatorial region posses several phenomena such equatorial ionization anomaly or ionospheric perturbations in auroral and cusp regions. The latitudinal distribution of these anomalies should be mapped during the whole mission. The effects are also highly dependent on space weather, on magnetospheric forces induced by solar, interplanetary and magnetospheric disturbances. Hence also coordination with LYRA and SWAP (other P2 payload) measurements would be useful to find a correlation between particular solar events and ionospheric disturbances.
- Ionospheric Perturbations by Solar Events: This scientific objective will use cooperation with LYRA and SWAP experiments and further more enhance the sphere of interest. Detected solar event, if possible, should start DSLP burst measurement when the solar event affects the Earth.
- Mapping Bulk Plasma Parameters: All acquired DSLP data will be used to map the bulk plasma parameters (primarily electron density and temperature) and to study their latitudinal and seasonal variations.
Instrument
The DSLP experiment represents a new type of a measuring device in the wide family of electrostatic Langmuir probes. The new technique used on this instrument consist in I-V characteristics acquisition from several independent sectors of a spherical shaped electrode. The probe will, therefore, provide measurements in situ directional diagnostics of surrounding plasma. This new concept, first tested on board French micro-satellite DEMETER, has been called the segmented Langmuir probe (SLP).
The new DSLP design for the Proba 2 mission is based on the SLP concept only and comprises two identical sensors. Both are spherical shaped probes divided into 7+1 independent segments (i.e., seven disc shaped segments on the sphere plus the rest of the conducting surface of the electrode). Both sensors of the DSLP experiment are mounted on the deployable back solar panel and the DSLP data processing unit (DPU) is accommodated inside the body of the Proba 2 satellite (see Figure 2). In addition to the classical measuring technique of electrostatic probes, the two identical SLP sensors of the DSLP instrument will be also tested as an electrical antenna. The E-field fluctuations can be sampled up to 2 MHz.
The DSLP instrument provides three measuring techniques:
- IMODE - current measurement (I-V characteristics acquisition) on all segments with time resolution of 1 full (i.e. all segments) sample per second
- PMODE - potential measurement (on guards only) with respect to the satellite ground, 8 measurements per second
- EMODE - high frequency measurement of potential between guards of the two SLP sensors, 2048 measurements per second
FACT SHEET
- Components: data processing unit (DPU), 2 multi-channel current-voltage converters, 2 identical sensors
- Sensors: spherical segmented electrodes (Æ 4 cm) - 7 disk-shaped segments, 1 guard segment
- Measurements: current-voltage characteristics (1 Hz), floating potential (8 Hz), E-field fluctuations (2 kHz)
- Sweep range: ±7.62 V, ±3.81 V, linear & logarithmic scale, 128 steps
- Current gain: ±20 μA, ±2 μA (guard) and ±1 μA, ±0.1 μA (segments)
- DAC: 16-bit
- Data rate: 19.2 kb/s (RS422)
- Power budget: 4.34 W (±10% during operations)
- Mass: total 3046 g (including TPMU box), sensor 410 g