  The 3rd generation partnership project (3GPP) completed the first global 5th
generation (5G) new radio (NR) standard in its Release 15, paving the way for
making 5G a commercial reality. So, what is next in NR evolution to further
expand the 5G ecosystem? Enabling 5G NR to support satellite communications is
one direction under exploration in 3GPP. There has been a resurgence of
interest in providing connectivity from space, stimulated by technology
advancement and demand for ubiquitous connectivity services. The on-going
evolution of 5G standards provides a unique opportunity to revisit satellite
communications. In this article, we provide an overview of use cases and a
primer on satellite communications. We identify key technical challenges faced
by 5G NR evolution for satellite communications and give some preliminary ideas
for how to overcome them.
