The Ariel mission: a mission of the European Space Agency for the characterization of exoplanets

Ariel, part of the European Space Agency's (ESA) Cosmic Vision science program, is an innovative medium-class mission designed for atmospheric remote sensing of exoplanets. It is the first mission solely dedicated to investigating the atmospheres of more than 500 transiting exoplanets, ranging from gas giants to super-Earths, using a combination of transit photometry and spectroscopy. The mission's primary goal is to analyze these exoplanets' chemical composition and thermal structures, paving the way for large-scale, comparative planetology. Ariel is scheduled for launch in 2029 aboard Ariane 6.2. It will operate from an orbit around the Sun-Earth system's second Lagrange point. The mission has a nominal lifetime of four years, with the potential for a two-year extension. The spacecraft comprises two main modules: the Service Module (SVM) and the Payload Module (PLM). The SVM manages platform elements, including attitude control, power, data handling, and communication systems. The PLM incorporates an all-aluminium cryogenic telescope with two scientific instruments, the Ariel IR Spectrometer (AIRS) and the Fine Guidance System (FGS). The Operational Ground Segment consists of ground stations and the Mission Operation Centre (MOC) located at ESOC, responsible for the operations of the spacecraft and instruments. The Science Ground Segment (SGS) consists of the Science Operation Centre (SOC), located at ESAC, along with the Instrument Operations and Science Data Centre (IOSDC) provided by the Ariel Mission Consortium (AMC). The SGS will perform the science mission planning as well as processing of the data to generate the mission data products and provision of the Ariel mission archive for the user community. While ESA holds overall responsibility for Ariel, the Ariel Mission Consortium is responsible for the procurement of the payload units, as well as managing the IOSDC. This collaborative effort aims to unlock the mysteries of exoplanetary atmospheres and deepen our understanding of these distant worlds

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit