# The ASPIICS solar coronagraph aboard the Proba-3 formation flying mission. Scientific objectives and instrument design

## TL;DR

The paper details the design and scientific goals of the ASPIICS coronagraph on ESA's Proba-3 mission, which uses a novel formation flying technique to observe the solar corona with unprecedented distance and clarity.

## Contribution

It introduces a new formation-flying solar coronagraph with a 144-meter baseline, enabling closer and clearer observations of the inner solar corona.

## Key findings

- First observations expected to reveal inner corona details
- Enhanced understanding of solar wind origins
- Insights into coronal mass ejection mechanisms

## Abstract

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.