(Guest post by Hirokuni Oda)
“Swarm science results after 2 years in space” was organized as one of the special issues of SpringerOpen journal “Earth, Planets and Space” (EPS). Swarm is a three-satellite constellation mission launched by the European Space Agency (ESA) on 22 November 2013. It consists of three identical spacecraft, two of which (Swarm Alpha and Swarm Charlie) are flying almost side-by-side in polar orbits at lower altitude (about 470 km in September 2016) with an East-West separation of 1.4° in longitude corresponding to 155 km at the equator. The third satellite (Swarm Bravo) is in a slightly higher orbit (about 520 km altitude in September 2016). Each of the three satellites carry a magnetometry package (consisting of absolute scalar magnetometer, fluxgate vector magnetometer, and star imager) for measuring the direction and strength of the magnetic field, and instruments to measure plasma and electric field parameters as well as gravitational acceleration. Time and position are provided by on-board GPS. The configuration of the various instruments on each of the three Swarm spacecraft is shown in Fig. 1. More information about the mission can be found at http://earth.esa.int/swarm.
The 21 articles collected in this special issue were stimulated by the Joint Inter-Association Symposium “JA4 Results from Swarm, Ground Based Data and Earlier Satellite Missions” at the 26th General Assembly of the International Union of Geodesy and Geophysics (IUGG) held in Prague in July 2015.