Tycho Brahe was a Danish astronomer of the 16th-17th century. The Tycho Project was named after him. (PROSE: The Last Sontaran) According to the Seventh Doctor, Brahe possessed a "scientific genius". (PROSE: Fable Fusion)
When Brahe was fourteen he witnessed a solar eclipse in Denmark. The fact that the eclipse was predicted inspired him to become an astronomer. (COMIC: Herald of Madness) He studied at Charles University in Prague. (PROSE: The Long Step Backward)
By 1601, Brahe became the court astronomer to Emperor Rudolf II. He took Johannes Kepler as a student and considered himself to be the world's greatest astronomer. While en route to a gathering at Castle Houska, he and Kepler met the Thirteenth Doctor, Graham O'Brien, Ryan Sinclair and Yasmin Khan in Kokorin Forest in Central Bohemia. He accepted that Team TARDIS was due to visit the same gathering and let them follow him. He was shown to be extremely popular upon arrival, being greeted with applause and requests for autographs.
Brahe quickly struck up a friendship with Graham, where he explained some supposed haunted legends of the castle. He was furious when Baroness Dagmar Ruskovitch took a greater interest in Kepler than him, and he went with Graham and Yaz to find out why during which he saw her attempting to teach Kepler facts from the future. She transformed into a centaur to try and kill the Doctor and her friends, although she was stopped by Kepler. Protesting, Tycho, Graham and Yaz were placed in the dungeon, although Yaz's quick thinking allowed them to escape, where Tycho discovered how the assembled astronomers had been paralysed by the Baroness' orbs. He quickly fought off the Baroness' guards as Graham and Yaz destroyed the orbs. As the Doctor and Yaz returned, they were visited by Ruskovitch's ally, Brother Dominik, and his Brethren, but Ryan made him run away instead of attacking. Encountering Ruskovitch again, Brahe attempted to attack her but was easily overpowered.
The group soon discovered that Ruskovitch and Dominik were actually trying to save the universe from the Catastrophia's Herald which was being manifested belowground, and Tycho banded the astronomers together to help seal it away. Kepler, leading, revealed that he would not survive the process, and Brahe forcibly took his place, knowing it was worth it if Kepler could leave his mark on the future. Despite Graham's protests, Brahe continued, finally discovering the secrets of the universe as he died saving the world. (COMIC: Herald of Madness)
After Brahe's death, he was given a state funeral by Emperor Rudolf, and his body was buried in a cemetery in Prague. In the 24th century, his body was unearthed by the Third Doctor and Sergeant Kandula during the search for the Tipping Device. The Doctor said he was "an old friend". (PROSE: Midnight in the Café of the Black Madonna)