Earth-Affecting Solar Causes Observatory (EASCO): A mission at the Sun-Earth L5

TL;DR

EASCO is a proposed mission at Sun-Earth L5 designed to improve measurements of CMEs and related space weather phenomena, addressing limitations of previous missions like SOHO and STEREO.

Contribution

The paper presents a detailed mission concept for EASCO, including payload, launch vehicle, propulsion, and operational plan, filling gaps in current space weather observation capabilities.

Findings

Payload can be accommodated on an intermediate launch vehicle.

Hybrid propulsion system is sufficient for L5 transfer.

Mission planned for 4-year operation around 2025 solar maximum.

Abstract

Coronal mass ejections (CMEs) and corotating interaction regions (CIRs) as well as their source regions are important because of their space weather consequences. The current understanding of CMEs primarily comes from the Solar and Heliospheric Observatory (SOHO) and the Solar Terrestrial Relations Observatory (STEREO) missions, but these missions lacked some key measurements: STEREO did not have a magnetograph; SOHO did not have in-situ magnetometer. SOHO and other imagers such as the Solar Mass Ejection Imager (SMEI) located on the Sun-Earth line are also not well-suited to measure Earth-directed CMEs. The Earth-Affecting Solar Causes Observatory (EASCO) is a proposed mission to be located at the Sun-Earth L5 that overcomes these deficiencies. The mission concept was recently studied at the Mission Design Laboratory (MDL), NASA Goddard Space Flight Center, to see how the mission can be implemented. The study found that the scientific payload (seven remote-sensing and three in-situ instruments) can be readily accommodated and can be launched using an intermediate size vehicle; a hybrid propulsion system consisting of a Xenon ion thruster and hydrazine has been found to be adequate to place the payload at L5. Following a 2-year transfer time, a 4-year operation is considered around the next solar maximum in 2025.