Celestia installation on Debian-based GNU/Linux distributions.

curl https://celestia.space/packages/celestia.key | sudo apt-key add -
deb https://celestia.space/packages SUITE COMPONENT | sudo tee /etc/apt/sources.list.d/celestia.list
Replace SUITE with your distribution codename (stretch, buster, xenial, bionic, focal) and COMPONENT with main if you use Debian or with universal if you use Ubuntu.