The ExoClock project is an open platform aiming to monitor exoplanets by integrating observations from space- and ground-based telescopes. This study presents an updated catalog of 620 exoplanet ephemerides, integrating 30,000 measurements from ground-based telescopes (the ExoClock network), literature, and space telescopes (Kepler, K2 and TESS). The updated catalog includes 277 planets from TESS which require special observing strategies due to their shallow transits or bright host stars. This study demonstrates that data from larger telescopes, and the employment of new methodologies such as synchronous observations with small telescopes, are capable of monitoring special cases of planets. The new ephemerides show that 45% of the planets required an update while the results show an improvement of 1 order of magnitude in prediction uncertainty. The collective analysis also enabled the identification of new planets showing transit-timing variations, highlighting the importance of extensive observing coverage. Developed in the context of the ESA’s Ariel space mission, with the goal of delivering a catalog with reliable ephemerides to increase the mission efficiency, ExoClock’s scope and service have grown well beyond the remit of Ariel. The ExoClock project has been operating in the framework of open science, and all tools and products are accessible to everyone within academia and beyond, to support efficient scheduling of future exoplanet observations, especially from larger telescopes where the pressure for time allocation efficiency is higher (Ariel, JWST, VLT, ELT, Subaru etc.). The inclusion of diverse audiences in the process and the collaborative mode not only foster democratization of science but also enhance the quality of the results.
We describe the scientific objectives and instrument design of the ASPIICS coronagraph launched aboard the Proba-3 mission of the European Space Agency (ESA) on 5 December 2024. Proba-3 consists of two spacecraft in a highly elliptical orbit around the Earth. One spacecraft carries the telescope, and the external occulter is mounted on the second spacecraft. The two spacecraft fly in a precise formation during 6 hours out of 19.63 hour orbit, together forming a giant solar coronagraph called ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun). Very long distance between the external occulter and the telescope (around 144 m) represents an increase of two orders of magnitude compared to classical externally occulted solar coronagraphs. This allows us to observe the inner corona in eclipse-like conditions, i.e. close to the solar limb (down to 1.099 Rs) and with very low straylight. ASPIICS will provide a new perspective on the inner solar corona that will help solve several outstanding problems in solar physics, such as the origin of the slow solar wind and physical mechanism of coronal mass ejections.
This paper presents a methodology to automate and accelerate the PLATO Payload (P/L) Boot Software (BSW) testing procedures by presenting a set of pre-programmed TCL scripts with different verification targets, satisfying the BSW requirements. These scripts are conceived in order to run an autonomous regression testing while verifying the BSW core functionalities, and in case of an additional BSW verification is needed, a set of scripts will be available for obtaining an automatic quick health-statement. The present method was proven by carrying out the pre-programmed functional and performance tests on the different PLATO's BSW versions installed on the ICU development models. The tests performed on these models have proven their effectiveness during the BSW testing process, since the testing time has been greatly reduced and the test results can be archived to maintain a useful record that contemporaneously with the dedicated TCL scripts may assist in future verification of the flight BSW version.
In the context of PLATO Camera Subsystem development, it has been decided to take advantage of MBSE methodologies using Enterprise Architect by Sparx Systems as tool. A Local SysML Camera model for PLATO mission(1) has been built from different Excel spreadsheets, i.e. Verification Control Matrices, released by Subsystems. Same approach has been used for the Camera-System itself. The complete flow-down of requirements has been created in order to easily identify and monitor any impact on the design due to changes, deviations and non-compliances. The model can be updated at any time importing Excel spreadsheet while it can be used as source to export documentation needed during formal reviews, both as Word and Excel files. In addition, Model architecture and constraints have been created through Block Definition Diagram and Internal Block Diagram so that structure, interfaces as well as interaction between different items, can be easily identified and monitored at both System and Subsystem level.
Ariel [1] [2] is the M4 mission of the ESA's Cosmic Vision Program 2015-2025, whose aim is to characterize by lowresolution transit spectroscopy the atmospheres of over one thousand warm and hot exoplanets orbiting nearby stars. It has been selected by ESA in March 2018 and adopted in November 2020 to be flown, then, in 2029. It is the first survey mission dedicated to measuring the chemical composition and thermal structures of the atmospheres of hundreds of transiting exoplanets, in order to enable planetary science far beyond the boundaries of the Solar System. The Payload (P/L) is based on a cold section (PLM - Payload Module) working at cryogenic temperatures and a warm section, located within the Spacecraft (S/C) Service Vehicle Module (SVM) and hosting five warm units operated at ambient temperature (253-313 K). The P/L and its electrical, electronic and data handling architecture has been designed and optimized to perform transit spectroscopy from space during primary and secondary planetary eclipses in order to achieve a large set of unbiased observations to shed light and fully understand the nature of exoplanets atmospheres, retrieving information about planets interior and determining the key factors affecting the formation and evolution of planetary systems.
PLAnetary Transits and Oscillations of Stars (PLATO), the third medium-class mission of the European Space Agency’s (ESA) Cosmic Vision program, is foreseen for launch in 2026 and stands out with its distinctive approach to exoplanet exploration [1]. The core of PLATO’s On-Board Data Processing System (DPS) is a crafted architecture that encompasses various components, including an Instrument Control Unit (ICU) and 12+2 Digital Processing Units (DPUs). These elements are interconnected through a SpaceWire network, which includes 6 routers. This network serves as a backbone for seamless communication among the different components of the Payload. The Application Software (ASW) of the Instrument Control Unit (ICU) plays a crucial role in the PLATO system’s operations. It takes over once the system has booted, the ASW is integral to overseeing critical functions essential for mission success. Its primary responsibilities encompass executing the day-to-day operations of the satellite. This includes managing data transmission, which involves both the collection and processing of data. The software adeptly handles ongoing tasks, adapts to different modes, and facilitates communication with ground control stations. Additionally, the ASW is responsible for configuring parameters for the Data Processing Unit (DPU), monitoring the Failure Detection, Isolation, and Recovery (FDIR) process and SW, conducting image stacking, and efficiently managing hardware compression. Remarkably, the ASW demonstrates its effectiveness by efficiently managing a daily data volume of 435 Gb on ground. On the other hand, the PLATO Boot Software (BSW) holds paramount importance in the mission, distinguished by its low complexity. The BSW ensures the integrity of the system startup process. It plays a fundamental role in the startup and maintenance operations of the ICU, engaging in essential tasks like board diagnostics and the initiation of the ASW. Its significance extends to crucial responsibilities such as systems and hardware initialization, including SpW communication, ensuring SDRAM integrity through systematic checks, generating comprehensive boot reports, maintaining a consistent heartbeat, managing housekeeping duties, and facilitating event generation. Its responsibilities also extend to overseeing the nominal boot sequence and executing telecommands. Together, the PLATO’s ICU BSW and ASW contribute to the satellite’s overall functionality. While the BSW focuses on the startup and initialization phase, the ASW oversees the continuous, mission-specific operations throughout the satellite’s time in space. The seamless transition from BSW phase to ASW phase is vital for the successful initialization and configuration of PLATO payload, enabling the satellite to fulfill its designated functions. This comprehensive transition phase ensures that the satellite will operate reliably and efficiently in its operational environment. Prior to initiating the ASW application, the BSW conducts a verification process to ensure that the ASW does not load into the section of SDRAM already utilized by the BSW. This process includes integrity checks where the BSW verifies the integrity of the compressed ASW image stored in NVM (Non-Volatile Memory) before decompressing it into SDRAM. Additionally, integrity checks are conducted on the ASW after it has been decompressed in SDRAM. Of particular significance is the TCL test verification and validation process, essential for ensuring the accuracy and reliability of the PLATO ASW startup post-boot. Rigorous testing and verification procedures, including software regression tests using a reprogrammed TCL script, are employed to validate PLATO ASW functionality. These tests, conducted on setup-configured images stored in MRAM memory, play a vital role in minimizing errors and ensuring PLATO mission success. This paper thoroughly explores the pivotal role played by the PLATO ICU BSW in the startup process. It emphasizes testing and verifying functionality to ensure the accurate startup of the ASW post-boot. The attainment of this goal involves launching setup-configured images stored in MRAM memory, executed through a reprogrammed TCL script designed for software regression tests. In conclusion, the seamless transition from BSW to ASW phase, supported by comprehensive TCL test verification and validation, is paramount for PLATO’s payload operational efficiency and success in fulfilling its scientific objectives.
Ariel [1] is the M4 mission of the ESA's Cosmic Vision Program 2015-2025, whose aim is to characterize by low-resolution transit spectroscopy the atmospheres of over one thousand warm and hot exoplanets orbiting nearby stars. The operational orbit of the spacecraft is baselined as a large amplitude halo orbit around the Sun-Earth L2 Lagrangian point, as it offers the possibility of long uninterrupted observations in a fairly stable radiative and thermo-mechanical environment. A direct escape injection with a single passage through the Earth radiation belts and no eclipses is foreseen. The space environment around Earth and L2 presents significant design challenges to all spacecraft, including the effects of interactions with Sun radiation and charged particles owning to the surrounding plasma environment, potentially leading to dielectrics charging and unwanted electrostatic discharge (ESD) phenomena endangering the Payload operations and its data integrity. Here, we present some preliminary simulations and analyses about the Ariel Payload dielectrics and semiconductors charging along the transfer orbit from launch to L2 included.
The PLAnetary Transits and Oscillations of stars (PLATO) is a space telescope under ESA development. The (PLATO’s) Instrument Control Unit (ICU) is an electronics box that is responsible for the management (MGT) of the payload (P/L), the communication with the Service Module (SVM), and the compression of scientific data before transmitting them as telemetries TMs to the SVM. The ICU receives data from 2 “fast” (F-DPU) each 2.5s and 24 normal Data Processing Units (N-DPU) each 25s. In order to reduce the huge data volume produced on-board by the 104 CCD (4 CCD per camera), for each target star it will be allocated a window, from which all the pixel values will be gathered, forming a small image called “imagette”. These cropped images are compressed by means of a lossless algorithm running in the ICU FPGA and transmitted as Packet Utilization Standard (PUS) packets to SVM. These streamlined transmissions require qualified compression and decompression techniques to preserve images. In this poster we propose a scripting tool that classifies and collects automatically telemetry PUS packets, hosting scientific data and metadata, to reconstruct compressed imagettes on-ground.
Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey mission (Tinetti 2019; Puig et al. 2018; Pascale et al. 2018), has been selected in March 2018 by ESA for the fourth medium-class mission (M4) launch opportunity of the Cosmic Vision Program, with an expected lift off in late 2028. It is the first mission dedicated to measuring the chemical composition and thermal structures of the atmospheres of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of our own Solar System. Its Payload (P/L) (Eccleston and Tinetti 2018; Eccleston et al. 2017; Middleton et al. 2019), has been designed to perform transit spectroscopy from space during primary and secondary planetary eclipses in order to achieve a large unbiased survey concerning the nature of exoplanets atmospheres and their interiors, to determine the key factors affecting the formation and evolution of planetary systems (Tinetti et al. 2017, 2018). Ariel will observe hundreds of warm and hot transiting gas giants, Neptunes and super-Earths around a wide range of host star types, targeting planets hotter than $\sim $ 600 K to take advantage of their well-mixed atmospheres. It will exploit primary and secondary transit spectroscopy in the 1.10 to 7.80 μm spectral range and broad-band photometry in the optical (0.50 - 0.80 μm) and Near IR (0.80 - 1.10 μm) . One of the two instruments of the Ariel Payload is the Fine Guidance System (FGS), including three photometric channels (two used for guiding as well as science) between 0.5-1.1 μm plus a low resolution NIR spectrometer for 1.1-1.95 μm range. Along with FGS an IR Spectrometer (AIRS) (Amiaux et al. 2017) is foreseen, providing low-resolution spectroscopy in two IR channels: Channel 0 (CH0) for the 1.95 − 3.90 μm band and Channel 1 (CH1) for the 3.90 − 7.80 μm range. Finally, an Active Cooler System (ACS) including a Ne Joule-Thomson cooler is adopted to provide active cooling capability to the AIRS detectors working at cryogenic temperatures. AIRS is located at the intermediate focal plane of the telescope and common optical system and it hosts two HgCdTe-based hybrid IR detectors and two cold front-end electronics (CFEE) for detectors control and readout. Each CFEE is driven by a Detector Control Unit (DCU) part of AIRS but hosted within and managed by the Instrument Control Unit (ICU) of the Payload (Focardi et al. 2018). ICU is a warm unit residing into the S/C Service Module (SVM) and it is based on a cold redundant configuration involving the Power Supply Unit (PSU) and the Commanding and Data Processing Unit (CDPU) boards; both DCUs are instead cross-strapped and can be managed by the nominal or the redundant (PSU+CDPU) chain. ICU is in charge of AIRS management, collecting scientific and housekeeping (HK) telemetries from the spectrometer and HK from the telescope (temperatures readings), the P/L Optical Bench (OB) and other Subsystems (SS), thanks to a warm slave unit (TCU, Telescope Control Unit) interfaced to the ICU. Science and HK telemetries are then forwarded to the S/C, for temporary storage, before sending them to Ground. Here we describe the status of the ICU design at the end of B1 Phase, prior to the Mission Adoption Review (MAR) by ESA, with some still open architectural choices to be addressed and finalised once selected the ICU industrial Prime contractor.
PROBA-3 is the forth of the PROBA technological mission designed by the European Space Agency. The main purpose of PROBA-3 is to demonstrate the capabilities of two different spacecraft to perform in-orbit formation flight. Furthermore, the two satellites will form a scientific instrument, a solar coronagraph, for acquiring relevant data related to the corona of the Sun. In order to make the mission feasible, several novel technologies compose the mission formation flight system. The Shadow Position Sensor (SPS) system is one of the metrological systems designed for providing the satellite relative position with an high level of accuracy.This paper describes the algorithm developed for providing the spacecraft relative position to the mission Guidance and Navigation Control System (GNC). Furthermore, the achieved results in terms of precision are presented. Lastly, an overview of the implemented logic, from the measurements acquisition to the computed position, is provided.
By comparing measured and expected polarization in the HI Ly alpha 121.6 nm coronal emission line it is possible to infer the magnetic field in the solar corona. PeNCIL is the ideal device to perform such a measurement. It is a light transmitting polarimeter optimized at 121.6 nm, completely free of mechanical moving parts, thought as part of an internally occulted coronagraph to be flown aboard a future small solar mission. Its optical components are in de Senarmont configuration: a fixed MgF2 quarter wave retarder, a nano-wire grid polarizer (nano-WGP) and a MgF2 variable retarder modulated through a calibrated piezo-clamp (PCVR). The nano-WGP and the PCVR represent a first-ever achievement in the history of technology development for VUV. The nano-WGP fabrication is at the edge of the current nanotechnology since the pitch between wires shall be 40 nm. The PCVR is based on a MgF2 parallelepipedic sample refractive index variations as produced by a piezo-electric clamp. This work addresses the status of the project with particular emphasis on the design and manufacturing of the nano-WGP and the PCVR.
The Atmospheric Remote-sensing Infrared Exoplanet Large-survey mission (ARIEL) (Tinetti et al. 2017) is one of the three present candidates for the ESA M4 (the fourth medium mission) launch opportunity. The proposed Payload (Eccleston et al. 2017; Morgante et al. 2017; Da Deppo et al. 2017) will perform a large unbiased spectroscopic survey from space concerning the nature of exoplanets atmospheres and their interiors to determine the key factors affecting the formation and evolution of planetary systems. ARIEL will observe a large number (>500) of warm and hot transiting gas giants, Neptunes and super-Earths around a wide range of host star types, targeting planets hotter than 600 K to take advantage of their well-mixed atmospheres. It will exploit primary and secondary transits spectroscopy in the 1.2 - 8m spectral range and broad-band photometry in the optical and Near IR (NIR). The main instrument of the ARIEL Payload is the IR Spectrometer (AIRS) (Amiaux et al. 2017) providing low-resolution spectroscopy in two IR channels: Channel 0 (CH0) for the 1.95 - 3.90m band and Channel 1 (CH1) for the 3.90 - 7.80m range. It is located at the intermediate focal plane of the telescope (Da Deppo et al. 2016, 2017, 2017) and common optical system and it hosts two IR sensors and two cold front-end electronics (CFEE) for detectors readout, a well defined process calibrated for the selected target brightness and driven by the Payload's Instrument Control Unit (ICU).
The Atmospheric Remote-sensing Infrared Exoplanet Large-survey mission (ARIEL) (Tinetti et al. 2017) is one of the three present candidates for the ESA M4 (the fourth medium mission) launch opportunity. The proposed Payload (Eccleston et al. 2017; Morgante et al. 2017; Da Deppo et al. 2017) will perform a large unbiased spectroscopic survey from space concerning the nature of exoplanets atmospheres and their interiors to determine the key factors affecting the formation and evolution of planetary systems. ARIEL will observe a large number (> 500) of warm and hot transiting gas giants, Neptunes and super-Earths around a wide range of host star types, targeting planets hotter than 600 K to take advantage of their well-mixed atmospheres. It will exploit primary and secondary transits spectroscopy in the 1.2 − 8μ m spectral range and broad-band photometry in the optical and Near IR (NIR). The main instrument of the ARIEL Payload is the IR Spectrometer (AIRS) (Amiaux et al. 2017) providing low-resolution spectroscopy in two IR channels: C h a n n e l 0 (C H 0) for the 1.95 − 3.90μ m band and C h a n n e l 1 (C H 1) for the 3.90 − 7.80μ m range. It is located at the intermediate focal plane of the telescope (Da Deppo et al. 2016, 2017, 2017) and common optical system and it hosts two IR sensors and two cold front-end electronics (CFEE) for detectors readout, a well defined process calibrated for the selected target brightness and driven by the Payload’s Instrument Control Unit (ICU).
PROBA-3 ESA's mission aims at demonstrating the possibility and the capacity to carry out a space mission in which two spacecrafts fly in formation and maintain a fixed configuration. In particular, these two satellites - the Coronagraph Spacecraft (CSC) and the Occulter Spacecraft (OSC) - will form a 150-meters externally occulted coronagraph for the purpose of observing the faint solar corona, close to the solar limb - i.e. 1.05 solar radii from the Sun's center ( R-circle dot). The first satellite will host the ASPIICS ( Association de Satellites Pour l'Imagerie et l'Interferometrie de la Couronne Solaire) coronagraph as primary payload. These features give to the PROBA-3 mission the characteristics of both, a technological and a scientific mission.Several metrology systems have been implemented in order to keep the formation-flying configuration. Among them, the Shadow Position Sensors (SPSs) assembly. The SPSs are designed to verify the sun-pointing alignment between the Coronagraph pupil entrance centre and the umbra cone generated by the Occulter Disk. The accurate alignment between the spacecrafts is required for observations of the solar corona as much close to the limb as 1.05 R-circle dot. The metrological system based on the SPSs is composed of two sets of four micro arrays of Silicon Photomultipliers (SiPMs) located on the coronagraph pupil plane and acquiring data related to the intensity of the penumbra illumination level to retrieve the spacecrafts relative position. We developed and tested a dedicated algorithm for retrieving the satellites position with respect to the Sun. Starting from the measurements of the penumbra profile in four different spots and applying a suitable logic, the algorithm evaluates the spacecraft tri-dimensional relative position. In particular, during the observational phase, when the two satellites will be at 150 meters of distance, the algorithm will compute the relative position around the ideal aligned position with an accuracy of 500 mu m within the lateral plane and 500 mm for the longitudinal measurement. This work describes the formation flying algorithm based on the SPS measurements. In particular, the implementation logic and the formulae are described together with the results of the algorithm testing.