Tranquility, also known as Node 3, is a module of the International Space Station (ISS). ESA and the Italian Space Agency had Tranquility built by Thales Alenia Space. A ceremony on November 20, 2009 transferred ownership of the module to NASA. On February 8, 2010, NASA launched the module on the Space Shuttle's STS-130 mission.

NASA held an online poll to name Node 3. Users were allowed to choose from among four provided names (Earthrise, Legacy, Serenity, and Venture), or to suggest their own. In early voting, fans of the science fiction TV series Firefly boosted "Serenity", also the name of the show and film's eponymous spacecraft, to the top with 86%. On the March 3, 2009, episode of The Colbert Report, host Stephen Colbert instructed his viewers to suggest "Colbert" as the name for Node 3 in the online poll.  Following Colbert's call to have the node named after him, several other groups attempted to influence the vote. For example, a number of different environmental groups promoted the name "Amazonia", after the Amazon Rainforest. They argued that the name was more appropriate given that Node 3 will include the station's environmental control systems. Humorist Dave Barry urged readers of his blog to name the node "Buddy", which finished as the sixth most popular user-suggested name. Gaia Online asked its users to "Send Gaia to Space" by naming the node "Gaia", referring to the Greek goddess of the planet Earth, and "Gaia" finished third among the user-suggested names. Other popular user suggestions included "myYearbook", "SocialVibe", "Ubuntu", and the name of Scientology's galactic overlord: "Xenu".  "Serenity" was the top choice among the NASA-provided names, with 70% of the vote, but finished second overall, losing to "Colbert" by more than 40,000 votes. The naming contest rules, however, state that although the poll results will be taken into account, NASA has ultimate discretion in choosing an appropriate name for the node. On April 6, 2009, Stephen Colbert, in jest, threatened a lawsuit if the node was not named after him. In addition, United States Congressman Chaka Fattah stated that he believes that paying attention to democracy and voting results should not be limited to earthbound organizations so he planned to use congressional power to force NASA to honor the winning Colbert write-in votes.  On April 14, 2009, astronaut Suni Williams appeared on The Colbert Report, and announced the name of the node would be Tranquility. The name was chosen in honor of the 40th Anniversary of the first lunar landing of Apollo 11 on the Sea of Tranquility. However, the treadmill the astronauts use for exercise has been named "C.O.L.B.E.R.T." for "Combined Operational Load Bearing External Resistance Treadmill" and is located in Tranquility. Colbert was thrilled and happily accepted this offer. The treadmill traveled to space aboard Space Shuttle mission STS-128 on August 28, 2009, for eventual installation in the Tranquility node during STS-130.

Why did they not name the whole ship "Colbert"?
although the poll results will be taken into account, NASA has ultimate discretion in choosing an appropriate name for the node.