Project Gemini was NASA‘s second human spaceflight program after it became evident to NASA officials that a follow-on to the Mercury program was required to develop advanced spaceflight capabilities in support of the USA objective to put men on the moon by the end of the decade as announced by President John F. Kennedy on May 25, 1961. Project Gemini carried ten, two man crews to Low Earth Orbit (LEO) missions from 1961 to 1966. Gemini also performed missions long enough to simulate an eight day, round trip to the moon and back as well as perfecting working outside the spacecraft with extra-vehicular activity (EVA). Gemini also pioneered the orbital maneuvers that would be necessary to achieve space rendezvous and docking so that Apollo could pursue its prime mission without doing these fundamental exploratory operations.

Astronauts Virgil I. “Gus” Grissom and John W. Young participated in the first crewed Gemini flight, Gemini III. Image Credit: NASA/MSFC archives

All Gemini flights were launched from Launch Complex 19 (LC-19) at Cape Kennedy Air Force Station in Florida. The actual launch vehicle was the Titan II, a modified Intercontinental Ballistic Missile (ICBM) that had been modified to carry men into space. Gemini was also the first program to use the newly built Mission Control Center at the Houston Manned Spacecraft Center for flight control.

Another first for the Gemini program, it was the first astronaut-carrying spacecraft to include an onboard computer to facilitate management and control of mission maneuvers. The Gemini Guidance Computer weighed about 59 lbs. and unlike Mercury, Gemini used in-flight radar and an artificial horizon indicators, similar to those used in airplanes. By contrast, astronauts of the Mercury program had no control over their flight path and later, computers flew most of Apollo missions. Each Gemini crew had full manual with control sticks for yaw, pitch and roll as the original intention was for Gemini to land on solid ground. This idea was ultimately dropped, and parachutes were used to make sea landings as in Mercury. However, unlike Mercury, Gemini was suspended at an angle closer to horizontal, so that a side of the heat shield contacted the water first. This eliminated the need for the landing bag cushion used in the Mercury capsule.


Another significant change from the Mercury Program was that Gemini did not use an escape tower powered by a solid-fuel rocket, but instead used aircraft-style ejection seats. The escape tower was determined by NASA to be heavy and complicated and NASA felt that ejection seats were sufficient to separate the astronauts from a malfunctioning launch vehicle. At higher altitudes, where the ejection seats could not be used, the astronauts would return inside the spacecraft, which would separate from the launch vehicle.

Crew members for Gemini included astronauts from the “Mercury Seven“, “The New Nine“, and the members of the 1963 astronaut class. Unfortunately, during the life of the Gemini program, three astronauts died in air crashes while training, including both members of the prime crew for Gemini 9. This mission was flown by the backup crew which was the only time a backup crew has completely replaced a prime crew on a mission in NASA’s history to date.


Estes Gemini-Titan


One of the first rockets created in the Apollo series, the Gemini Titan [#K-12] was released in 1967 and ran until 1973. Modeled after the GT-3, this 25 inch tall semi-scale, skill level 4 model was considered challenging to build. Powered by two 18mm engines, it required an Estes FS-5 Launch Control System and a 12V car battery to ignite the two engines which propelled the 3.8 oz rocket into the atmosphere. Only experienced rocketeers were encouraged to tackle the launching of this rocket. Clear fins were used to help stabilize the rocket in flight without detracting from the overall appearance. One 24 inch parachute was used to provide the Gemini-Titan with a soft landing back on earth. 

After a 13 year hiatus, the Gemini-Titan was re-released in 1988 [#1978] for a limited time. The 1:73 scale model was an easier to build skill level 2 and stood over 19 inches tall.  This version of the Gemini-Titan weighed in at 2.15 ounces, 1.65 ounces lighter than the original model. No longer requiring two engines for power, this version was converted to a one engine system. The removable clear plastic fin unit was still attached for flights over 600 ft high and recovery was reduced to a 12 inch parachute. Gone again in 1989, the Gemini-Titan is still not available today.

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