The Event Horizon Telescope (EHT) recently produced the first horizon-scale image of a supermassive black hole. Expanding the array to include a 3-meter space telescope operating at >200 GHz enables mass measurements of many black holes, movies of black hole accretion flows, and new tests of general relativity that are impossible from the ground.
@article{arxiv.1909.01405,
title = {Studying black holes on horizon scales with space-VLBI},
author = {Kari Haworth and Michael D. Johnson and Dominic W. Pesce and Daniel C. M. Palumbo and Lindy Blackburn and Kazunori Akiyama and Don Boroson and Katherine L. Bouman and Joseph R. Farah and Vincent L. Fish and Mareki Honma and Tomohisa Kawashima and Motoki Kino and Alexander Raymond and Mark Silver and Jonathan Weintroub and Maciek Wielgus and Sheperd S. Doeleman and Jose L. Gomez and Jens Kauffmann and Garrett K. Keating and Thomas P. Krichbaum and Laurent Loinard and Gopal Narayanan and Akihiro Doi David J. James and Daniel P. Marrone and Yosuke Mizuno and Hiroshi Nagai},
journal= {arXiv preprint arXiv:1909.01405},
year = {2019}
}