Pavel Andreyevich Chekov, a character from the fictional Star Trek universe, was the Navigator and Weapons Officer on the Starship Enterprise under Captain Kirk. His rank was ensign in Star Trek: The Original Series, but was promoted to the rank of lieutenant in Star Trek: The Motion Picture and commander in subsequent movies. Chekov was Russian, but was played by the Lithuanian-American actor Walter Koenig.
Popular legend holds that Star Trek creator Gene Roddenberry added Chekov's character in the show's second season in response to being told about a Pravda article which noted that although the Soviet Union was a leader in space exploration, the international crew of the Enterprise lacked Soviets. Including someone from Russia, the long-time cold war adversary of the U.S., matched well with Roddenberry's vision of an ideal future in which the people of the Earth were united. In truth, the evidence suggests that no such article was ever actually published in Pravda. 
A running joke involving Chekov's character was his tendency to credit everything to Mother Russia; for example, his claim that Scotch whisky was invented by "A little old lady in Leningrad." (This joke was later thrown back at Chekov in Star Trek VI: The Undiscovered Country in which a Klingon claims Shakespeare's Hamlet for his own people.)
One of Chekov's most memorable scenes and storylines comes in the second Star Trek film, Star Trek II: The Wrath of Khan, in which his character is put under the control of Khan through the use of a worm that crawls in Chekov's ear.
It may be of interest to note that while many alien species mastered the English language well enough to reach native proficiency, Chekov was never able to lose his accent. This was a dramatic convention so that viewers would not forget that he was from Russia.
A counter point to this observation is the fact that aliens do not really speak English. The sounds they produce when speaking are translated by the universal translator and then repeated in Federation Standard English. Of course, this form of the language has no accent. But Chekov is not speaking Russian. He is personally speaking English, thus, the accent is maintained. (The only time Chekov has ever been heard speaking Russian on screen is in Star Trek III: The Search For Spock and Star Trek: Generations).
By 2367, during the time of Star Trek: The Next Generation, there is a Starfleet vessel named in honor of Pavel Chekov. The vessel was destroyed by the Borg during the Battle of Wolf 359. (The script originally called for the ship to be named USS Chekhov after Anton Chekhov, but the art department thought it was a spelling error, and labeled the ship USS Chekov. The destroyed hulk of the starship - which is sometimes shown at conventions - clearly shows the name USS Chekov; note the different spelling of the name).