The Galis Expedition was the first mission sent to find the planet Krop Tor. They found that it did indeed exist and orbited K37 Gem 5 as if it were a star rather than a black hole. The Galis Expedition brought back artefacts, including a notebook and some ancient pottery. (WC: Tardisode 8)
The Galis Expedition was followed by the Walker Expedition. (TV: The Impossible Planet)