From this answer:
Spektr-R's orbit allows it to get as far from Earth as possible in order to produce a long baseline for Very Long Baseline Interferometry (VLBI)
Spektr-R (or RadioAstron) is a Russian scientific satellite with a 10 m (33 ft) radio telescope on board. It was launched on 18 July 2011, by Zenit-3F launcher, from Baikonur Cosmodrome to perform research on the structure and dynamics of radio sources within and beyond our galaxy. Together with some of the largest ground-based radio telescopes, this telescope forms interferometric baselines extending up to 350,000 km (220,000 mi).
I've used it in an example in the (currently unanswered) question What is the largest antenna deployed in space?
Currently Spektr-R is in the news because of a technical issue, (as is and was recently Hubble) but this question is about the years of observational radioastronomy that has been done.
Question: What are Spectr-R's major contributions to radio astronomy that could not have been done from Earth?
The answer would not have to be as elaborate as @Hobbes' answer to What kind of ground-based radio astronomy is NASA's DSN used for? Who are the PIs?