Shuttlecraft Sagan:

The shuttlecraft "Sagan" was named in honor of the late 20th century astronomer and Pulitzer Prize winning author, Doctor Carl Sagan, who pioneered exobiology and promoted the Search for ExtraTerrestrial Intelligence. Dr. Sagan made seminal contributions to the study of planetary atmospheres, planetary surfaces, the history of the Earth, and exobiology. He contributed to most of the unmanned missions that explored Earth's solar system.

The highlights of Sagan's career include the discovery of the high surface temperatures of the planet Venus, and solving the mysteries of what were believed to be "seasonal changes" to the planet Mars. He was among the first to hypothesize that Saturn's moon, Titan, and Jupiter's moon, Europa, may possess oceans, or lakes, making the them potentially habitable for life. Europa's subsurface ocean was later indirectly confirmed by the spacecraft Galileo. Sagan also helped solve the mystery of the reddish haze seen on Titan, revealing that it is composed of complex organic molecules constantly raining down to the moon's surface. He also speculated about life in Jupiter's clouds, given the planet's dense atmospheric composition, rich in organic molecules.

Sagan is best known, however, for his research on the possibilities of extraterrestrial life, including an experimental demonstration of the production of amino acids from basic chemicals by radiation. His research has been credited as having transformed planetary science.

Shuttlecraft Gemini:

The shuttlecraft "Gemini" was named for the third constellation of the Zodiac and its twin stars, Castor and Pollux and in honor of NASA's second manned space flight program, which tested orbital rendezvous and docking, maneuvering and atmospheric entry methods.

Shuttlecraft Horch:

(destroyed in the episode "The Price Of Anything")

The shuttlecraft "Horch" was named for professional prop maker Steve Horch who lost his battle with cancer in 2010. Horch, along with fellow master modeler Michael Moore, founded HMS Creative Productions in 1998, specializing in the manufacturing of original movie and tv production props and licensed reproduction collectibles, toy and product prototype manufacturing and consulting, and rare prop and model preservation and restoration. Although Horch's credits are not limited to the Star Trek universe, he has made props and set re-creations for several Star Trek exhibits, including The Star Trek Experience, the Star Trek travelling exhibit and museum tour, the Star Trek exhibit at the Edinburgh Museum, and the Canada Star Trek Museum. His television credits include props and set pieces for The Next Generation, Deep Space Nine, Voyager and Enterprise. His movie credits include Star Treks IV, V and VI, Generations, First Contact, Insurrection, Nemesis, and the 2009 re-boot.

Shuttlecraft Hartford:

The shuttlecraft "Hartford" was named in honor of the USS Hartford; the flagship of Rear Admiral David G. Farragut during the Battle of Mobile Bay, August 5, 1864.

Shuttlecraft Lovell:

The shuttlecraft "Lovell" was named in honor of American Astronaut James A. Lovell.  During NASA's Project Gemini flights, Lovell, aboard Gemini VII, participated in the first rendezvous of two manned maneuverable spacecraft and commanded Gemini XII.  During Project Apollo, he served as Command Module Pilot and Navigator aboard Apollo VIII - man's maiden voyage to the moon in December of 1968. Apollo VIII was the first manned spacecraft to be lifted into near-earth orbit by the Saturn V launch vehicle and became the first manned spacecraft to leave the Earth's gravitational influence.  Lovell completed his fourth mission as Commander of Apollo XIII in April of 1970, and became the first human to journey twice to the moon.