Ernest Shackleton

 was an Earth explorer.

On 16 January 1909, Shackleton's expedition fell just short of reaching the South Pole and therefore failed to notice the pair of Krynoid seedpods that had crashed there. (PROSE: Time Traveller's Diary)

Following two failed expeditions to reach the South Pole, Shackleton led the Imperial Trans-Antarctic Expedition to cross Antarctica. In 1915, the expedition's ship the Endurance was trapped in the ice. When the biologist Robert Clark had begun turning into a Skith after being in contact with a whale whose DNA was altered by the Skith, a group including some of Shackleton's crew, joined by the Tenth Doctor and Martha Jones, followed Clark to the Skith ship Oppressor One. The Skith imprisoned the group and prepared to study and dissect them, but after Shackleton got through to Clark, Clark released them. Martha brought most of the group apart from the Doctor and Shackleton back to the Endurance in the TARDIS. Shackleton saved the Doctor from being killed by the Skith Leader, and helped the Doctor stop the Skith's plan to destroy Earth when the Skith deemed their own expedition a failure. Martha saved the Doctor and Shackleton's lives by returning to Oppressor One in the Doctor's TARDIS. After being brought back to the Endurance, Shackleton and fellow explorer Frank Wild came up with a plan to travel 250 miles west to Paulet Island, leaving the expedition abandoned. The Doctor mentioned that everyone on the expedition survived. (COMIC: The First)