The Doctor's capsule

From Tardis Wiki, the free Doctor Who reference

The Doctor's capsule was a two-person space capsule which the Fourth Doctor kept in the TARDIS.

When the TARDIS went back in time forty-five hundred million years, the Doctor and Sarah Jane Smith used the capsule three times to observe Earth's development from space at intervals millions of years apart. (AUDIO: Exploration Earth [+]Loading...["Exploration Earth (audio story)"])