The MARs Boundary Layer Lidar experiment (MARBLL): Winds at last on Mars!

International audienc

The MARs Boundary Layer Lidar experiment (MARBLL): Winds at last on Mars!

International audienc

The MARs Boundary Layer Lidar experiment (MARBLL): Winds at last on Mars!

International audienc

Thermal tests of birefringent plates in molecular adhesion for spatial ultra-violet polarimetry

International audienceHigh-resolution spectropolarimetry is a technique used to study many astronomical objects including stellar magnetic fields. It has mainly been used on ground for optical and, more recently, infrared (IR) observations. Space mission projects including ultra-violet (UV) high-resolution spectropolarimetry, such as Pollux onboard LUVOIR proposed to NASA, are being studied in Europe under CNES leadership. Bringing a spectropolarimeter into space means that the instrument should be prepared for space environment including temperatures. The UV polarimeter we are considering is composed by a rotating modulator and an analyzer. Both components are made of magnesium fluoride (MgF<SUB>2</SUB>). The modulator is a rotating block of waveplates in molecular adhesion, each plate having its own fast axis. The analyzer is a Wollaston prism, also made with molecular adhesion. MgF<SUB>2 </SUB>being birefringent, the plates and prism are anisotropic and will dilate and retract due to thermal changes differently along their fast and slow axes. Each plate having its own fast axis, the thermal changes will create stress at the interfaces, i.e. at the molecular adhesion between the plates. This study focuses on the most critical part: the plates of the modulator. To demonstrate the resistance of the modulator and increase its technological readiness level (TRL), an optical bench including interferometry has been set at the Paris Observatory. It allows us to observe in real time the state of the molecular adhesion between plates as they are submitted to thermal changes in a vacuum chamber. Additional samples have been tested in a thermal vacuum chamber at CNES. This article describes the modulator using molecular adhesion, the test experiments, and the conclusion of this thermal study. Although molecular adhesion broke in 2 samples during thermal cycling, most samples survived which provides encouraging results for this technique

The MARs Boundary Layer Lidar experiment (MARBLL): Winds at last on Mars!

International audienceMARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity. MARBLL thus guarantees that performancesexceed baseline requirements for all dust opacities (from 0.2 to 5),with an optimum estimated around 0.7, lying close to the average dust MARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity. MARBLL thus guarantees that performancesexceed baseline requirements for all dust opacities (from 0.2 to 5),with an optimum estimated around 0.7, lying close to the average dust MARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity

The MARs Boundary Layer Lidar experiment (MARBLL): Winds at last on Mars!

International audienceMARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity. MARBLL thus guarantees that performancesexceed baseline requirements for all dust opacities (from 0.2 to 5),with an optimum estimated around 0.7, lying close to the average dust MARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity. MARBLL thus guarantees that performancesexceed baseline requirements for all dust opacities (from 0.2 to 5),with an optimum estimated around 0.7, lying close to the average dust MARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity

The MARs Boundary Layer Lidar experiment (MARBLL): Winds at last on Mars!

International audienceMARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity. MARBLL thus guarantees that performancesexceed baseline requirements for all dust opacities (from 0.2 to 5),with an optimum estimated around 0.7, lying close to the average dust MARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity. MARBLL thus guarantees that performancesexceed baseline requirements for all dust opacities (from 0.2 to 5),with an optimum estimated around 0.7, lying close to the average dust MARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity

The MARs Boundary Layer Lidar Experiment: Mars Winds at last!

MARBLL is an optical remote sensing in- strument using a mature state-of-the-art Doppler wind lidar technology specifically designed to operate at the surface of Mars. The instrument includes an emitting device (laser) and a spectral analyzer (Mach-Zehnder interferometer). Wind profiling is inferred from the 1064 nm beam emit- ted by the laser and subsequently backscattered to the telescope by the suspended aerosols. The received signal has a Doppler shift induced by the radial velocity component of the particles, which is quantified by the interferometer

The MARs Boundary Layer Lidar experiment (MARBLL): Winds at last on Mars!

International audienceMARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity. MARBLL thus guarantees that performancesexceed baseline requirements for all dust opacities (from 0.2 to 5),with an optimum estimated around 0.7, lying close to the average dust MARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity. MARBLL thus guarantees that performancesexceed baseline requirements for all dust opacities (from 0.2 to 5),with an optimum estimated around 0.7, lying close to the average dust MARBLL is an optical remote sensing instrument using a maturestate-of- the-art Doppler wind lidar technology specifically designedto operate at the surface of Mars. The instrument includes an emittingdevice (laser) and a spectral analyzer (Mach-Zehnder interferometer).Wind profiling is inferred from the 1064 nm beam emitted by the laserand subsequently backscattered to the telescope by the suspendedaerosols. The received signal has a Doppler shift induced by theradial velocity component of the particles, which is quantified by theinterferometer.Doppler wind lidars (DWL) offer a unique combination of accuracy andspatial resolution making them the most efficient technique to profilewinds in the terrestrial boundary layer (see e.g. Gentry, 2000;Frehlich, 2008). Existing DWL methods usually require aquasi-monochromatic laser emission and a precise frequency lockingbetween the emitter and the spectral analyzer to infer the windDoppler shift. These requirements lead to specific laser designs(single mode emission) associated with delicate servo-loops. Thetechnical readiness level (TRL) of such systems remains too low toplan their use in the upcoming Mars missions. The conceptual approachof MARBLL started from this consideration: instead of developingspace-qualified lasers to meet specific system detection requirements,MARBLL concept was led by the idea to design a detection systemmatching the specifications of an existing space-qualified laser(ChemCam) and by the need to guarantee high performances in the harshMartian environment. The mature MARBLL design, which has undergonefive years of Research and Development (R&D), ensures highperformances for a large range of temperature and for any atmosphericcondition (e.g. dust opacity) known to prevail on Mars. The relativedetection method of MARBLL does not require the use of frequencycontrol for both the emitter and the spectral analyzer. MARBLL willbe able to derive wind velocity and orientation with a typicalaccuracy of respectively 0.1 to 10 m/s and 1 to 10◦, a dynamic rangeof ±272 m/s and with a vertical resolution of 50 m up to 1 km withinthe first 5 km above the surface. Aerosol abundance can be retrievedup to 10 km with a vertical resolution ranging from 50 meters to 1500m. Atmospheric dust loading affects MARBLL performances in aquantified way: high dust opacities (>2) reduce the sounding depthcapability by >1 km, but increases SNR in the lowest atmosphericlayers. At the laser wavelength, dust is non-absorbing and allphotons are scattered, maintaining high levels of backscattered fluxeven at high dust opacity

The MICADO first-light imager for the ELT: towards the preliminary design review of the MICADO-MAORY SCAO

International audienceMICADO is the European ELT first-light imager, working in the near-infrared at the telescope diffraction limit. Provided by MAORY, the ELT first-light adaptive optics module (AO), MCAO will be the primary AO mode of MICADO, driving the design of the instrument. MICADO will also come with a SCAO capability. Developed under MICADO's responsibility and jointly by MICADO and MAORY, SCAO will be the first AO mode to be tested at the telescope, in a phased approach of the AO integration at the ELT. The MICADO-MAORY SCAO preliminary design review (PDR) will occur in November 2018. We present here different activities and results we have had in the past two years preparing this PDR, covering several fields (opto-mechanics, electronics, real-time and control software, integration and tests, AO simulations and performance, prototyping) and the different SCAO subsystems (pyramid wavefront sensor, calibration unit, real-time computer, dichroic and the so-called Green Doughnut which hosts the SCAO assembly as well as the MAORY MCAO natural guide star wavefront sensors)