The INTEGRAL Mission

The INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL; Winkler et al. 2003; Kuulkers et al. 2021) was launched onboard a Proton-DM2 rocket on 17 October 2002 at 06:41 CEST, from Baikonur in Kazakhstan. The mission is currently providing long, uninterrupted observations (up to about 47 h per satellite orbit of 2.7 days) with a large field-of-view (fully coded: 100 deg2), millisecond time resolution, keV energy resolution, polarization measurements, in the hard X-ray to gamma-ray range, as well as additional wavelength coverage at X-ray and optical wavelengths. Besides the long, scheduled observations, INTEGRAL can rapidly (within a couple of hours) re-point and conduct Target of Opportunity Observations on a large variety of sources.INTEGRAL observations and their scientific results have been building an impressive legacy: the discovery of currently more than 600 new high-energy sources, first-ever direct detection of 56Ni and 56Co radioactive decay lines from a Type Ia supernova, spectroscopy of isotopes from galactic nucleosynthesis sources, new insights on the enigmatic positron annihilation in the galactic bulge and disk, and pioneering gamma-ray polarization studies. INTEGRAL is also a successful actor in the new multi-messenger astronomy introduced by non-electromagnetic signals from gravitational waves and from neutrinos: INTEGRAL, together with Fermi, observed the first prompt electromagnetic radiation in coincidence with a binary neutron-star merger.