The development of several new state-of-the-art spacecraft to support crewed operations in Earth orbit and beyond has been in the news much in recent months. As we wait for the first crewed test flights of these new ships, it should be remembered how much their development and eventual success owe to an often forgotten program called Gemini. Capable of maneuvering in orbit for rendezvous and docking with other spacecraft while supporting a crew for periods of weeks as they performed a range of useful tasks, it can be argued that Gemini was the first true “spaceship” ever to fly. And as exciting as the first test flights of today’s new crewed spacecraft may be, they do not not compare with the feelings when the first crewed flights of Gemini were flown a half a century ago.

The Origin of Gemini

The purpose of the Gemini program was to develop the technologies and techniques needed to fulfill President Kennedy’s goal of landing a man on the Moon by 1970. While the six manned Mercury missions flown from May 1961 to May 1963 provided important information on how to get a single human into space, survive for periods of several hours while performing simple tasks and return safely home, the Mercury spacecraft was too small and its capabilities too limited to prepare us for the Moon.

NASA planners recognized this and on December 7, 1962 they officially announced the Mercury Mk II program which was subsequently renamed Gemini on January 3, 1963. The major objectives of the program were:

– Demonstrate that humans and their equipment could survive up to two weeks in space

– Demonstrate rendezvous and docking techniques in orbit

– Demonstrate the technology and techniques needed to perform EVAs

Meeting all of these objectives was necessary if Apollo were to be successful.

Gemini was a two-man spacecraft that was roughly conical in shape with a base diameter of 3.3 meters which stood 5.8 meters tall. Built by the prime contractor of the Mercury spacecraft, McDonnell Aircraft Corporation (which merged with Douglas in 1967 to become McDonnell Douglas which then merged with Boeing 30 years later), it consisted of two major sections: The first was the reentry module, which housed the crew in orbit and returned them to Earth, and the second was an adapter section. The adapter section, which connected the reentry module to the launch vehicle during ascent, consisted of a retrograde section which held a set of four solid retrorockets used to start the descent to Earth from orbit and an equipment section which housed in-orbit propulsion systems, life support, power systems and all other equipment not needed for the return to Earth.

With a typical launch mass of 3,700 kilograms (over twice that of the earlier Mercury spacecraft), Gemini needed a modified Titan II ICBM to get into orbit. Built by Martin Marietta (which subsequently merged with Lockheed in 1995 to form the aerospace giant, Lockheed Martin), the two-stage Titan II was the largest operational rocket available at the time. Many modifications were needed to man-rate the Titan II GLV (Gemini Launch Vehicle) as well as smooth out its performance to safely carry astronauts into orbit.

These modifications were tested during the unmanned Gemini 1 mission launched on April 8, 1964 (see “The Mission of Gemini 1”). Since many of the key spacecraft systems were still not ready for flight at the time of launch, the mission of Gemini 1, in addition to testing the Titan II GLV, was simply to get into orbit to verify Gemini’s structural integrity and provide three orbits’ worth of information on spacecraft performance while remaining attached to the spent second stage of the launch vehicle. No recovery of Gemini 1 was planned or attempted and the spacecraft was allowed to burn up during reentry four days after its launch. One more unmanned test flight would be required to certify Gemini’s other systems.

Preparing for Manned Flight

Just five days after the successful launch of Gemini 1, the crew for the first manned Gemini flight was introduced by the Director of the Manned Spacecraft Center, Robert Gilruth, during a press conference. The primary crew for Gemini 3 consisted of USAF Maj. Virgil “Gus” Grissom as the mission’s command pilot and USN Lt. Cdr. John Young as the pilot. The 38-year old Grissom was a veteran of the Mercury program and had flown America’s second manned space mission, Mercury-Redstone 4. Launched on July 21, 1961, his Liberty Bell 7 capsule successfully returned to Earth after a 15-minute suborbital flight but subsequently sank in the Atlantic Ocean when its hatch was prematurely blown open during recovery by a faulty circuit breaker (see “A History of Suborbital Crewed Spaceflights“). Grissom’s backup was fellow Mercury veteran, USN Capt. Walter Schirra, who had flown in Sigma 7 for a six-orbit mission in October 1962. Flying with Grissom on the Gemini 3 mission was the 33-year old Young who was selected to be part of NASA’s second astronaut group in September 1962. Young’s backup for this mission was fellow rookie astronaut, USAF Maj. Thomas Stafford, who was also part of NASA’s second group of astronauts.

As the quartet of men began intensive training for their mission, the plan at this time was for the Gemini 2 unmanned test flight to take place towards the end of August 1964 with the launch of Gemini 3 slated for mid-November with about a month of slack in the schedule. Unfortunately, ongoing problems with the final certification of key systems of the innovative Gemini spacecraft and delays in the preparation of the second spacecraft for the last test flight ate up that slack and much more. By the time Spacecraft No. 2 arrived at Cape Kennedy on September 21, the launch of Gemini 2 had slipped to mid-November with the Gemini 3 mission coming no earlier than the end of January 1965.

But as technical issues continued to cause more schedule slips, the Soviet Union beat the first two-man Gemini mission into orbit by launching a three-man crew on Voskhod 1. Launched on October 12, 1964, the one-day Voskhod 1 mission had an Apollo-size crew in orbit years ahead of the US maintaining the Soviet’s lead in the Space Race as a result (see “The Mission of Voskhod 1”). After a launch attempt on December 9 that was aborted at ignition due to a failure in the Titan’s hydraulic system, Gemini 2 was finally launched on its suborbital test flight on January 19, 1965. It successfully tested Gemini’s key systems during an 18-minute flight which ended with the splashdown of the reentry module 3,422 kilometers downrange (see “The Mission of Gemini 2”).

With a pair of successful unmanned test flights completed, the way was now clear for the manned Gemini 3 mission. Grissom and Young had used the delays in the launch of their mission to accrue time training intensively in order to improve the odds of success. Grissom had put in 77 hours of time in the flight simulator at Cape Kennedy with Young logging a total of 85 hours. Grissom and Young had also rehearsed 225 and 154 aborts, respectively, in a launch simulator in Texas in case something went wrong. Schirra and Stafford had comparable totals in their roles as the backup crew. The astronauts also went through extensive parachute training since, unlike Mercury or the later Apollo which used a solid rocket motor to pull the capsule away from the launch vehicle in case of an abort, Gemini included ejection seats to provide launch abort options during the first 50 seconds after liftoff.

After Spacecraft No. 3 arrived at Cape Kennedy on January 4, 1965 and completed its initial check out, Grissom and Young spent time in its cockpit for additional checks and training. After Titan GLV-3 serial number 62-12558 had been erected at Launch Complex 19 (LC-19) on January 25 less than a week after the launch of Gemini 2, Spacecraft No. 3 joined the stack with final mechanical mating completed on February 17. Initially scheduled for launch on March 22, by March 15 the official launch date was pushed back by one day by NASA Headquarters to accommodate the limited launch window of NASA’s final Ranger lunar mission (see “The Mission of Ranger 9”).

Grissom and Young performed a final rehearsal of their mission in their spacecraft at LC-19 on March 18, 1965. With this task successfully completed, the crew of Gemini 3 had logged a total of 33 hours in Spacecraft No. 3 which had been quasi-officially nicknamed “Molly Brown” after the popular Broadway musical and 1964 film, “The Unsinkable Molly Brown” – an hommage to Grissom’s incident with Liberty Bell 7. But as the crew of Gemini 3 were preparing for their last simulated flight test, the Soviet Union successfully launched the two-man Voskhod 2 into orbit on a one-day mission. During the beginning of the second orbit, Alexei Leonov performed the first EVA (extravehicular activity) once again beating NASA which was planning to perform an EVA during the upcoming Gemini 4 mission (see “The Mission of Voskhod 2”).

Overshadowed by the spectacular Voskhod 2 mission, the objectives of the Gemini 3 flight were relatively modest. The goal for the short 4½-hour long mission was to verify the performance of the Gemini spacecraft in preparation for the more ambitious missions to follow. Gemini 3 was to go into low orbit, perform a number of orbit-changing maneuvers as well as other system checks and return the crew safely home after three orbits. Almost as an afterthought, some simple scientific experiments were added to the mission. Experiment S-2 was designed to test the effects of weightlessness on the development of sea urchin egg growth while Experiment S-4 was meant to examine the effects of radiation on human blood cells. A technology-related experiment included on the flight, designated T-1, was a holdover from the Mercury program and was designed to inject water into the hot plasma surrounding the spacecraft during reentry to see if this could help reduce the effects of communication blackout during reentry. Earth photography using handheld cameras rounded out the tasks for the mission.

The Launch of Gemini 3

Finally, on the morning of March 23, 1965, everything was ready to go. Gus Grissom and John Young were woken up at about 5:00 AM EST and had a traditional steak and egg breakfast after a brief medical checkup. Afterwards, the astronauts were taken to a pre-flight ready room at LC-16 which had been used for USAF Titan ICBM test flights until 1963 when it was transferred to NASA to support Gemini. Here they donned their new G3C spacesuits. Afterwards, it was a short van ride to LC-19 where a fully fueled Gemini-Titan 3 stood ready for launch. By the time the pair of astronauts had made it up the gantry to the white room to enter their spacecraft about 20 minutes ahead of schedule, Schirra and Stafford had already been there for a couple of hours performing system checks and setting switches. By 7:30 AM, Grissom and Young were strapped in their seats and the hatches were secured.

A minor leak in an oxidizer line in the first stage of the Titan II and the threat of bad weather caused a hold at T-35 minutes after the astronauts had been in the capsule for about an hour. The countdown resumed 24 minutes later after the leak was fixed and the clouds began to clear. Except for a later complaint from the astronauts about the amount of time spent on their backs waiting for launch, everything went well with the countdown. Finally at 9:24 AM EST, Gemini 3 lifted off with Capcom Gordon Cooper announcing, “You’re on your way Molly Brown.”

At first, Grissom and Young barely noticed that liftoff had occurred except that the ship’s clock started running. But as Gemini-Titan 3 burned up propellant and gained altitude, the astronauts were slowly pressed into their seats as the acceleration eventually built up to six Gs just before first stage engine cutoff. After a brief orange flash engulfed the ship as the second stage ignited 2 minutes and 36 seconds after launch, the 3,237-kilogram Gemini 3 continued to accelerate towards orbit. The strong “pogo” effect that had plagued the ICBM version of the Titan II had been resolved in the GLV resulting in a very smooth ride. After 5 minutes and 38 seconds of powered flight, the second stage shutdown and Gemini 3 was in orbit.

Following separation from the last stage, Grissom fired Gemini’s OAMS (orbit attitude and maneuvering system) engines slightly longer than planned until a mission elapsed time of 6 minutes and 9 seconds to enter a 122 by 175-kilometer orbit inclined 32.5 degrees to the equator. Safely in orbit, the astronauts then set about performing their checks and preparing for their in-orbit activities. Except for Young accidentally breaking the handle on the S-2 cell growth experiment to activate it and Grissom noting a tendency for Gemini 3 to drift to the left in yaw, all seemed to be going well. The yaw problem was eventually traced to venting from a water boiler in the equipment section.

About 90 minutes into the flight, the OAMS engines were fired for 75 seconds to cut the spacecraft’s velocity by 15 meters per second to enter a nearly-circular 161 by 172-kilometer orbit. About 45 minutes and half an orbit later, Grissom fired Gemini’s translational thrusters to change the inclination of the orbit by 1/50th of a degree as part of a series of small maneuvers. NASA made a big deal of this at the time as another “space first” but the reality is that other spacecraft had experienced orbit plane changes as part of deorbit burns or injection burns to higher orbits, the Moon or beyond, successful or otherwise, since such maneuvers are never perfectly coplanar even when they are intended to be so (perhaps it would be accurate enough to characterize this as the first intentional orbit plane change). For the last major maneuver 4 hours and 21 minutes after launch, Grissom fired the aft-firing OAMS thrusters for 2 minutes and 27 seconds while over the Pacific Ocean cutting Gemini’s velocity by 29 meters per second and dropping the perigee to only 72 kilometers. This “fail safe” maneuver ensured that Gemini 3 would reentry Earth’s atmosphere even in the event of a retrorocket failure resulting in a landing farther downrange in the South Atlantic near Ascension Island.

Between performing maneuvers to be used in later Gemini flights for rendezvous and docking missions, Grissom and Young took pictures and performed other experiments. While there was no official meal break during this short mission, Young was tasked with making an evaluation of the food and the waste collection system for an hour during the second orbit. To Grissom’s surprise, John Young pulled out a corned beef sandwich he had stowed away in one of his pockets in probably the most famous episode of the Gemini 3 mission. Wally Schirra had picked up the sandwich at a favorite eatery in Cocoa Beach called “Wolfie’s” and had slipped it to Young while they were in the white room during the countdown. Grissom only took a couple of bites of the contraband sandwich before realizing that the crumbs might present a problem for the on board systems. Because of the fallout after the mission over this incident, members the astronaut corps were banned from repeating this stunt on any future missions. After stowing the sandwich, Young then proceeded his “official” evaluation by reconstituting some apple sauce and grapefruit juice and opened a package of chicken bites. Young did not have sufficient time to fully evaluate the food or waste disposal system but did have some recommendations based on his experiences including allotting extra time for meal preparation, eating and clean up on future missions.

Coming Home

Near the end of the third revolution as Gemini 3 was dropping towards its 72-kilometer perigee, Gus Grissom and John Young were preparing to come home. After Grissom used the OAMS thrusters to orient the spacecraft, the equipment section was jettisoned and the four solid retrorocket motors were fired one at a time in quick succession. Shortly after the retrograde section was jettisoned, Gemini began its reentry. At an altitude of 90 kilometers, Young activated the T-1 experiment that injected water into the hot plasma surrounding the reentering spacecraft. Ground stations monitoring the descending capsule noted that there was a definite increase in C-band and UHF telemetry signal strength as a result.

But as the Gemini 3 reentry module descended towards its primary landing zone off Grand Turk Island in the Atlantic Ocean, it was noted that the capsule was off course despite Grissom’s attempts to steer the craft towards the recovery zone. Apparently the capsule was not producing as much lift as had been predicted by the wind tunnel tests. Unfortunately, since Gemini 2 flew a “zero-lift” ballistic descent during the only Gemini reentry test two months earlier, this shortfall was left to be discovered by Gemini 3.

Despite coming down short of the target area, the reentry of Gemini 3 proceeded as expected. The drogue chute was deployed at an altitude of 15,000 meters followed by the main parachute canopy at 3,230 meters. All was going well until the descending capsule transitioned from the vertical under single point suspension to a two-point suspension with the nose only 35° above the horizontal. This attitude was designed to lessen the impact at splashdown but the sudden transition made the astronauts heads snap violently forward. Grissom hit the windshield mounting bracket so hard that he cracked the faceplate of his helmet. Except for this unexpected jolt, Gemini 3 successfully splashed down without incident at 2:16:31 PM EST about 86 kilometers short of its planned landing point after a flight of 4 hours, 52 minutes and 31 seconds.

With the aircraft carrier the USS Intrepid 110 kilometers away, Grissom opted for a pickup from a helicopter dispatched from the US Coast Guard cutter Diligence only a few kilometers away instead waiting hours until the Navy carrier arrived to pluck the capsule out of the water as had been originally planned. Still thinking of the incident with the sinking of Liberty Bell 7, Grissom kept the hatches closed until Navy swimmers had arrived and attached a flotation collar about a half hour after splashdown. Experiencing sea sickness, Grissom and Young wasted no time getting out of the increasingly uncomfortable capsule and were hoisted aboard the waiting helicopter.

After arriving on the USS Intrepid about an hour and a quarter after splashdown, Grissom and Young began days of medical exams and debriefings. There was even a congratulatory phone call from President Lyndon Johnson. After being recovered from the Atlantic by the USS Intrepid 90 minutes after the astronauts arrived, the Gemini 3 reentry module began its own “exams and debriefings” having survived the flight in excellent shape. While there was some disappointment about the results of the science experiments flown at the last minute, overall the mission of Gemini 3 was a great success. The way was now clear for future flights to attempt increasingly longer and more complex missions. The next mission of Gemini 4, whose crew had already been selected and been training for eight months, was now cleared to attempt an EVA as part of a four-day flight scheduled for launch in just two months (see “The Forgotten Mission of Gemini 4“).

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Related Video

Here is an excellent NASA documentary from 1965 entitled “All Systems Go” which gives details of all the preflight testing required to prepare the Gemini spacecraft for the Gemini 3 mission.

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Here is another excellent NASA documentary, “Gemini Status Report No. 2”, showing the development activities of the Gemini program between January 1, 1964 to January 31, 1965 leading up to the first manned flight.

Related Reading

“The Mission of Gemini 2”, Drew Ex Machina, January 19, 2015 [Post]

“The Mission of Gemini 1”, Drew Ex Machina, April 8, 2014 [Post]

“The Mission of Voskhod 1”, Drew Ex Machina, October 12, 2014 [Post]

“The Mission of Voskhod 2”, Drew Ex Machina, March 18, 2015 [Post]

General References

David Baker, The History of Manned Space Flight, Crown Publishers, 1981

Barton C. Hacker and James M. Grimwood, On the Shoulders of Titans: A History of Project Gemini, SP-4203, NASA History Division, 1977

David J. Shayler, Gemini: Steps to the Moon, Springer-Praxis, 2001

“NASA Schedules First Manned Gemini Flight from Cape Kennedy”, NASA Release No. 65-81, March 17, 1965