Solar Orbiter (SolO)

Solar Orbiter (SolO) is an ESA space probe that is part of the Cosmic Vision program. SolO is going to be launched in February 2019. Its mission is to explore the Sun - our nearest star - with unprecedented resolution at wavelength ranges that cover visible, extreme ultra violet, and X-rays. SolO will boldly perform in-situ measurements that no other probe has done before.

SolO will approach the Sun up to a perihelion distance of about 60 solar radii (0.28 astronomical units, i.e., an astronomical unit corresponds to the distance between Earth and Sun). SolO will be in a resonant orbit around the Sun with Venus. With each gravity assist maneuver at Venus which SolO will perform every third orbit around the Sun, its inclination will increasing up to about 30° with respect to the solar equator. Therefore SolO will permit close-up and high-latitude studies of the Sun.

Solar Orbiter Payload
Accommodation of Solar Orbiter's remote sensing instruments and in-situ instruments (image courtesy of ESA)

SolO will be equipped with a set of in-situ and a set of remote sensing instruments.
The in-situ instruments are designed to measure and observe the environmental conditions in the immediate vicinity of the spacecraft, whereas the remote sensing instruments will observe the Sun's surface and atmosphere in great detail.

The Leibniz-Institut für Astrophysik Potsdam (AIP) significantly contributes to the development of the remote sensing instrument STIX. Furthermore AIP is involved in the development of the in-situ instruments constituted by EPD/HET&EPT as well as EPD/STEIN.

Spectrometer/Telescope for Imaging X-rays (STIX)

STIX is a state to the art imaging X-ray telescope. It provides imaging spectroscopy with highest ever spatial resolution and sensitvity of solar thermal and non-thermal X-ray emission.

Flight model of STIX Imager and Detector Electronics Box

Flight model of STIX imager (front) and detector electronics box (rear)

The two main parts (i.e., the imager and the detector electronics box) of STIX are mounted independently on the spacecraft. The imager consists of 32 pairs of X-ray opacque tungsten grids mounted in front of 32 solid-state Cadmium Telluride X-ray detectors which are located on the electronics box and make up the spectrometer.

STIX will cover the energy range between 4 keV and 150 keV with an energy dependent resolution of 1 keV to 15 keV. Its finest angular resolution and temporal resolution are 7 arcsec and 0.1 seconds, respectively.

During the SolO mission STIX will address scientific topics such as, timing, location, intensity, and spectra of accelerated electrons as well as of high temperature thermal plasmas, mostly associated with flares and/or micro flares. Thus STIX will provide the high-energy link between surface and in-situ observations.

Further references:

ESA: Solar Orbiter - Mission
ESA: Publications
ESA: Solar Orbiter SOC repository of public documentation

STIX: Project Website