Space VLBI 2020: Science and Technology Futures Conference Summary
  The "Space VLBI 2020: Science and Technology Futures" meeting was the second
in The Future of High-Resolution Radio Interferometry in Space series. The
first meeting (2018 September 5--6; Noordwijk, the Netherlands) focused on the
full range of science applications possible for very long baseline
interferometry (VLBI) with space-based antennas. Accordingly, the observing
frequencies (wavelengths) considered ranged from below 1~MHz (> 300 m) to above
300~GHz (< 1 mm). For this second meeting, the focus was narrowed to mission
concepts and the supporting technologies to enable the highest angular
resolution observations at frequencies of 30~GHz and higher (< 1 cm).
  This narrowing of focus was driven by both scientific and technical
considerations. First, results from the RadioAstron mission and the Event
Horizon Telescope (EHT) have generated considerable excitement for studying the
inner portions of black hole (BH) accretion disks and jets and testing elements
of the General Theory of Relativity (GR). Second, the technologies and
requirements involved in space-based VLBI differ considerably between 100~MHz
and 100~GHz; a related consideration is that there are a number of existing
instruments or mission concepts for frequencies of approximately 100~MHz and
below, while it has been some time since attention has been devoted to space
VLBI at frequencies above 10~GHz.
  This conference summary attempts to capture elements of presentations and
discussions that occurred.
