Didier Morancais

ALADIN: the lidar instrument for the AEOLUS mission

The ALADIN Instrument is a Doppler Wind Lidar, which will be launched in 2007 aboard the ESA Core Explorer Aeolus Mission. The main purpose of this payload is the measurement of tropospheric wind profiles on a global scale. The concept is based on a solid-state Nd:YAG laser associated with a direct detection frequency receiver. Astrium-SAS is prime contractor for the development of ALADIN. This program includes in particular the development of a Pre Development Model for the critical parts of the instrument. This paper describes the flight instrument design and reviews the achievements of the PDM activities: this will cover in particular the development status of the engineering models of the CCD detectors, front-end units and spectrometers.

Predevelopment of a direct detection Doppler wind lidar for ADM/AEOLUS mission

The Atmospheric Dynamics Mission (ADM-Aeolus) has been selected as the second of a series of Earth Explorer Core Missions. The payload aims at providing measurements of atmospheric wind profiles with global coverage. The key element of ADM-Aeolus is the Atmospheric Laser Doppler Lidar Instrument (ALADIN), a Direct Detection Doppler Lidar. The ALADIN instrument belongs to a completely new class of earth-observation lidar payloads with limited power requirements and high reliability over a three-year lifetime. Technological challenges are addressed in an early stage by the development of a Pre-Development Model (PDM), which is a functional representative model of the receiver of ALADIN. The PDM is being established to validate the technologies used in the ALADIN design, evaluate the flight-worthiness of its major subsystems and verify the instrument overall performances. The purpose of this paper is to present the latest results on the status of the ALADIN Pre-Development Model.

Results of the pre-development of ALADIN, the Direct Detection Doppler Wind Lidar for ADM/AEOLUS

Due for launch in late 2007, the Atmospheric Dynamics Mission (ADM-Aeolus) has been selected as the second Earth Explorer Core Missions within ESA Living Planet Programme. Its payload aims at providing measurements of atmospheric wind profiles with global coverage. The key elecment of ADM-Aeolus is the Atmospheric LAser Doppler Lidar INstrument (ALADIN), a Direct Detection Doppler Lidar in the ultra-violet spectral region operating with aerosol and molecular backscatter signals in parallel. The ALADIN instrument belongs to a completely new class of earth-observation payloads with limited power requirements and high reliability over a three-year lifetime. It will be the first European Lidar in space. Technological challenges are addressed in an early stage by a pre-development programme that consists of designing, manufacturing and testing a functional representative model of the receiver of ALADIN (the Pre-Development Model, PDM), and a breadboard of the transmitter. The pre-development programme is being established to validate the technologies used in the ALADIN design, evaluate the flight-worthiness of its major subsystems and verify the instrument overall performances. The purpose of this paper is to present the main achievements of the pre-development programme: environmental tests on the Pre-Development Model (thermal-vacuum and mechanical tests), development of the laser breadboards and assessment programme of the laser diodes.

The atmospheric lidar instrument (ATLID)

Abstract The paper describes the design and performances of the Atmospheric Lidar instrument. ATLID is a backscatter lidar and a candidate for a future Polar Mission of ESA (beyond ENVISAT-1). The instrument uses a solid-state Nd-Yag laser (1.06 μm wavelength) and a 0.8 m diameter telescope. A linear scanning (+/− 40°) ensures the required swathwidth (1400 Km). The selected concept consists of a lightweight scanning telescope associated to a contra-rotative flywheel for torque compensation.

ALADIN, the first wind lidar in space: development status

The Atmospheric LAser Doppler INstrument (ALADIN) is the payload of the ADM-AEOLUS mission, which aims at measuring wind profiles as required by climatology and meteorology users. ALADIN belongs to a new class of Earth Observation payloads and will be the first Wind Lidar in space. The instrument comprises a high energy laser and a direct detection receiver operating on aerosol and molecular backscatter signals in parallel. ALADIN is now in its final construction stage: the Opto-Structural-Thermal-Model (OSTM) has been completed and successfully tested, mo st of the flight equipments have been delivered and the integration of Flight Model (FM) has started. The Aeolus satellite is developed for the European Space Agency with EADS Astrium as prime contractor for the satellite and the instrument.

ALADIN Doppler Wind Lidar : Recent advances

The Atmospheric Laser Doppler Instrument (ALADIN) is the payload of the ADM-Aeolus mission, which will provide direct measurements of global wind fields. It will determine the wind velocity component normal to the satellite velocity vector. The instrument is a direct detection Doppler Lidar operating in the UV, which will be the first of its kind in space. ALADIN comprises a high energy laser and a direct detection receiver operating on aerosol and molecular backscatter signals in parallel. The laser is all solid-state, based on Nd-YAG technology and high power laser diodes. The detector is a silicon CCD whose architecture allows on-chip accumulation of the returns, providing photon counting performance. The 1.5 m diameter telescope is lightweight, all made of silicon carbide. ALADIN is now in its final construction stage: the integration of the Flight Model is on-going. Most of the subsystems have been integrated; the payload performance and qualification test campaign will commence. This paper briefly describes the instrument design and provides insights on the development status and the results obtained so far. This regards in particular the receiver performance, the telescope development and the challenges of the laser. The Aeolus satellite is developed for the European Space Agency by EADS Astrium Satellites as prime contractor for the satellite and the instrument.

Manufacturing of an airborne demonstrator of ALADIN: the direct detection Doppler wind lidar for ADM-Aeolus

Due for launch in 2008, the Atmospheric Dynamics Mission (ADM-Aeolus) has been selected as ESAs second Earth Explorer Core Missions within its Living Planet Programme. Its payload aims at providing measurements of atmospheric wind profiles with global coverage. The key element of ADM-Aeolus is the Atmospheric LAser Doppler Lidar INstrument (ALADIN), a Direct Detection Doppler Lidar in the ultra-violet spectral region operating on aerosol and molecular backscatter signals in parallel. The ALADIN instrument belongs to a completely new class of active optical earth-observation payloads with limited power requirements and high reliability over a three-year lifetime. It will be the first European Lidar in space. Technological challenges have been addressed in an early stage by a pre-development programme that consisted of designing, manufacturing and testing a functional representative model of the receiver of ALADIN (the Pre-Development Model, PDM), and a breadboard of the transmitter. The pre-development programme has been successfully completed and both receivers and transmitter are being refurbished in an airborne configuration. The ALADIN airborne instrument demonstrator (A2D) will be used for ground and airborne campaigns prior to the launch of the satellite. This paper presents the main characteristics of the airborne instrument and the goals of the campaigns.

ALADIN: the first european lidar in space

The Atmospheric LAser Doppler INstrument (ALADIN) is the payload of the ESA’s ADMAEOLUS mission, which aims at measuring wind profiles as required by the climatology and meteorology users. ALADIN belongs to a new class of Earth Observation payloads and will be the first European Lidar in space. The instrument comprises a diode-pumped high energy Nd:YAG laser and a direct detection receiver operating on aerosol and molecular backscatter signals in parallel. In addition to the Proto- Flight Model (PFM)., two instrument models are developed: a Pre-development Model (PDM) and an Opto-Structure-Thermal Model (OSTM). The flight instrument design and the industrial team has been finalised and the major equipment are now under development. This paper describes the instrument design and performance as well as the development and verification approach. The main results obtained during the PDM programme are also reported. The ALADIN instrument is developed under prime contractorship from EADS Astrium SAS with a consortium of thirty European companies.

ADM-Aeolus follow-on missions

ADM-Aeolus is a dedicated satellite to provide global observations of vertical wind profiles. It will demonstrate the capability of a spaceborne Doppler wind lidar to accurately measure wind profiles. Thus the mission addresses one of the major deficiencies of the present Global Observing System. Simulations show that the wind profiles from Aeolus will improve Numerical Weather Prediction analyses and forecasts in the tropics and extra tropics. Aeolus is a precursor for an operational wind profiler system. It is under development for the European Space Agency with Astrium Satellites as prime contractor. Launch is planned in 2009 for a 3 year mission. There is likely to be a significant gap between the nominal end of life of Aeolus in late 2012, and the availability of wind profiles from post-EPS instruments in 2019 or later. The presentation will sketch a programme to fill this gap. It is based on copies of the present Aeolus satellite with minor modifications, such as finer vertical sampling, an alternative line-of-sight, and measures to increase lifetime. The programmatics required to fill the data gap will be discussed.

Atmospheric lidar predevelopment program (ATLID)

The Atmospheric Lidar (ATLID) is the backscatter lidar instrument developed for ESA, under the prime contractorship of MATRA MARCONI SPACE France. This kind of lidar has been selected for flight on an ESA Earth Explorer satellite, and will be based on ATLID concept and technologies. It is part of a multi-payload mission, named Earth Radiation, dedicated to the Earth radiative transfer study for climatology. The lidar will provide information on the atmosphere, such as cloud cover, top height of all cloud types and planetary boundary layer, thin cloud extent, optical depth and polarization. The instrument features a pulsed diode-pumped Nd-YAG laser (1.06 micrometers wavelength) together with a one-axis scanning 60 cm lightweight telescope. A technology pre-development program has been performed in order to raise the maturity of the instrument design. Elegant breadboard models have been realised and submitted to environmental tests. The laser transmitter, the laser thermal control subsystem (capillary-pumped two-phase loop), the diode laser power supply, the avalanche photodiode detection chain, the narrow-band filter, the scan mechanism, and the telescope lightweight primary mirror (C-SiC) have been breadboarded in the frame of the programme. The instrument design and performance have also been consolidated with regards to the successful hardware results.