The Solar Orbiter mission -- Science overview (2009.00861v1)

Abstract: Solar Orbiter, the first mission of ESA's Cosmic Vision 2015-2025 programme and a mission of international collaboration between ESA and NASA, will explore the Sun and heliosphere from close up and out of the ecliptic plane. It was launched on 10 February 2020 04:03 UTC from Cape Canaveral and aims to address key questions of solar and heliospheric physics pertaining to how the Sun creates and controls the Heliosphere, and why solar activity changes with time. To answer these, the mission carries six remote-sensing instruments to observe the Sun and the solar corona, and four in-situ instruments to measure the solar wind, energetic particles, and electromagnetic fields. In this paper, we describe the science objectives of the mission, and how these will be addressed by the joint observations of the instruments onboard. The paper first summarises the mission-level science objectives, followed by an overview of the spacecraft and payload. We report the observables and performance figures of each instrument, as well as the trajectory design. This is followed by a summary of the science operations concept. The paper concludes with a more detailed description of the science objectives. Solar Orbiter will combine in-situ measurements in the heliosphere with high-resolution remote-sensing observations of the Sun to address fundamental questions of solar and heliospheric physics. The performance of the Solar Orbiter payload meets the requirements derived from the mission's science objectives. Its science return will be augmented further by coordinated observations with other space missions and ground-based observatories.

• The paper presents extensive mission insights, detailing objectives to decipher solar wind drivers and coronal dynamics.
• It outlines a methodological approach combining near-Sun in-situ measurements with advanced remote-sensing to capture high-resolution solar data.
• The mission design leverages gravity assists and collaborative instrument payloads to advance our understanding of solar-heliospheric interactions.

The Solar Orbiter Mission: An Analytical Overview

The paper presents an extensive overview of the Solar Orbiter mission, emphasizing its scientific objectives, instrument payload, and mission design. As a collaborative effort between ESA and NASA, Solar Orbiter aims to enhance our understanding of the Sun-heliosphere interaction from a perspective not previously achieved by other solar missions.

Science Objectives

Solar Orbiter is tasked with addressing four critical solar physic questions:

1. Understanding the drivers of the solar wind and the genesis of the coronal magnetic field.
2. Analyzing how solar transients drive heliospheric variability.
3. Investigating solar eruptions and their role in producing energetic particle radiation.
4. Deciphering the functioning of the solar dynamo and its impact on Sun-heliosphere connections.

The mission's approach involves combining near-Sun in-situ measurements with remote sensing of the Sun, facilitating the exploration of solar coronal heating, CME (Coronal Mass Ejection) dynamics, and solar energetic particle events.

Instruments and Payload

Solar Orbiter carries a suite of ten instruments: six remote-sensing and four in-situ, managed by a collaboration of ESA member states and NASA. These instruments are designed to make intricate measurements of the solar atmosphere and the solar wind's particles, enabling comprehensive paper across multiple domains of solar physics.

• Remote-sensing instruments include EUI (Observing the EUV spectrum), Metis (a coronagraph), SO/PHI (for polarimetry and helioseismology), SoloHI (heliospheric imaging), SPICE (EUV imaging spectrometer), and STIX (X-ray observing capability).
• In-situ instruments are equipped to capture data on energetic particles, magnetic fields, radio and plasma waves, and solar wind properties, including EPD, MAG, RPW, and SWA instruments.

These instruments were particularly selected to achieve the high-resolution mapping needed for determining the origins of solar wind and understanding solar transients.

Mission Design and Operations

Launched aboard an Atlas V 411 rocket, Solar Orbiter is set on a trajectory that involves gravity assists from both Venus and Earth, culminating in a heliocentric orbit. The mission's design allows perihelion approaches of 0.28 AU as well as achieving high heliographic latitudes, providing a unique vantage point for solar observations.

The mission plan includes a nominal mission phase and potential extended missions, with each phase aligned with achieving specific scientific priorities. Coordinated operations among payload instruments and with other missions like NASA’s Parker Solar Probe are central to maximizing the science return. Earth-based operational centers are responsible for the management and dissemination of data.

Implications and Speculations

The expected results from Solar Orbiter will address long-standing uncertainties regarding solar wind origins and dynamics. By advancing heliophysics, these findings can potentially mitigate space weather risks and contribute to improved computational models for stellar dynamics.

As future developments, the insights gained from Solar Orbiter may offer pathways for more nuanced models of magnetic dynamo processes in not only our solar context but also in understanding other celestial bodies' magnetic activities.

In conclusion, the Solar Orbiter mission represents a pioneering step in solar exploration with its strategic payload and mission design, aimed at unraveling the intricate interplay between the Sun and its surrounding corona and heliosphere from close quarters and novel angles. This will enrich our understanding of solar dynamics and their broader cosmic significance.