The primary objectives of Gemini 3 were to 1) demonstrate manned orbital flight; 2) evaluate the two-man design, 3) demonstrate and evaluate the tracking network, 4) demonstrate the Orbital Attitude and Manoeuvring System (OAMS) capability in orbital manoeuvres and in retrofire backup, 5) demonstrate controlled re-entry and landing, 6) evaluate major spacecraft subsystems, 7) demonstrate systems checkout, pre-launch, and launch procedures, 8) demonstrate and evaluate recovery procedures and systems. This was primarily a testing shakedown for the new, manoeuvrable Gemini capsule.

The secondary objectives were to 1) evaluate flight crew equipment, biomedical instrumentation, and personal hygiene system, 2) perform 3 experiments, 3) evaluate low-level longitudinal oscillations (Pogo) of the Gemini Launch Vehicle and 4) general photographic coverage in orbit.

This was the first time the United States sent two astronauts into space at the same time but it was not only Gus Grissom's mission but also his vehicle from the very beginning. Because of his Mercury experience, Grissom was assigned to the Gemini spacecraft and became very close to the McDonnell engineers and technicians who were building it. So close that the first three cockpits were designed around him, giving him the best view of the instrument panel and out the window. It was later dubbed the " GUSMOBILE" because, as his pilot John Young would later say, "He was the only one that could fit inside without banging his head on the hatch."

Grissom was one of the smaller astronauts and as it turned out, 14 of the 16 astronauts could not fit into the cabin as designed, and all later cockpits had to be modified. For Tom Stafford (Gemini VI and IX) both his seat and the hatch had to be modified to accommodate his six-foot frame. While this was truly Grissom's vehicle, it was what Young smuggled onboard that would later cause some new and more stringent rules about what the astronauts might take with them on future missions.

In a joking reference to the sinking of Liberty Bell 7 on the second suborbital Mercury mission, Gemini 3 became the only one of the Gemini missions to get a "nickname." Subsequent Gemini missions only received numbers, and were numbered with Roman numerals. Officially the flight was Gemini 3, unofficially it was the voyage of "Molly Brown."

During Project Mercury, each pilot had named his own spacecraft, although Cooper had some trouble selling NASA on Faith 7 for the last spacecraft in the program. Grissom and Young now had the same difficulty with "Molly Brown." Grissom had lost his first ship, Liberty Bell 7, which sank after a faulty circuit blew the hatch before help arrived. "Molly Brown," the "unsinkable" heroine of a Broadway stage hit, seemed to Grissom the logical choice for his second space command. NASA's upper echelons thought the name lacking in dignity; but since Grissom's second choice was "Titanic," they grudgingly consented, and the name remained "Molly Brown," though only quasi-officially.

With a "You're on your way, Molly Brown," from CapCom (capsule communicator) L. Gordon Cooper, Jr., the third flight of Gemini, the first to which men entrusted themselves, began at 9:24 Tuesday morning, March 23 1965. The lift-off was so smoothly that neither Grissom nor Young felt anything. Their real cues were seeing the mission clock on the instrument panel start running and hearing Cooper announce it from mission control.

When the first-stage engine cut off two and a half minutes later, acceleration plunged from six g's to one. The second-stage engine ignited, bathing the spacecraft in a flash of orange-yellow light that was a normal product of fire-in-the-hole staging - that is, second-stage ignition before, instead of after, separation. The launch vehicle had slightly exceeded its predicted thrust, but a warning from Cooper prepared the pilots for the larger than expected pitch down when the second stage took over the steering. Young, who had never been in space before, was entranced by his view of Earth's horizon and the sense of rapid motion as second-stage thrust built up.

Five and a half minutes after launch, the second-stage engine shut down. The pop of the pyrotechnics that severed spacecraft from launch vehicle sounded like the bark of howitzers to Young. Grissom fired the aft thrusters to kick the spacecraft into orbit. He lost track of the time and fired too long, ending up with his incremental velocity indicator showing a slight over speed. But he wound up with an orbit of 122 by 175 kilometres, very close to the intended 122 by 182 kilometres.

About 20 minutes into the first orbit, just after "Molly Brown" passed beyond range of the mid-Atlantic Canary Island tracking station, the oxygen pressure gauge in the environmental control system reported an abrupt drop. Young, assigned to watch this gauge, naturally assumed that something was wrong with the system. But a quick glance showed odd readings on several other meters and suggested that the real trouble might be in the instrument power supply. Young switched from the primary to the secondary electrical converter to power the dials, and the problem vanished. The whole episode, from Young's first notice of the anomalous reading to his shift from primary to secondary power, took 45 seconds, one clear payoff from intense pre-flight training.

Gemini 3 crew did chalk up at least one historic first by manoeuvring in orbit. The first OAMS burn came an hour and a half after launch and lasted a carefully timed 75 seconds, cutting spacecraft speed by 15 meters per second and dropping it into a nearly circular orbit. Three quarters of an hour later, during the second revolution, Grissom fired the system again, this time to test the ship's translational capability and shift the plane of its orbit by one-fiftieth of a degree. During the third pass, Grissom completed the fail-safe plan with a two and a half minute burn that dropped the spacecraft's perigee to 72 kilometres and ensured re-entry even if the retrorockets failed to work.

Another somewhat historical first was the corned beef sandwich that made it into space. Wally Schirra, always the jokester, bought it at "Wolfie's" in Cocoa Beach and gave it to Young, who smuggled it on board the spacecraft. Schirra would later say that he had to cater the sandwich for Grissom and Young since they could not get takeout while in space. When it was time for the crew to eat the space food they carried, Young brought out the sandwich and handed it to Grissom. Gus jokingly said that Young would probably get in trouble because there was no mustard on it. Grissom, who ate only a few bites since he wanted no crumbs floating around the cabin, was right.

Something of a storm later blew up when the press got wind of the sandwich in space. When the news got to Congress, the lawmakers were upset. What was not made clear, apparent to either the legislators or the press was that the official food was only there for evaluation of its taste, convenience, and reconstitution properties and had nothing to do with any scientific or medical objectives of the mission. No one expected to learn very much about the effects of space food on so short a flight. The fracas did, however, produce some new and more stringent rules about what the astronauts might take with them on future missions.

As the three-orbit mission neared its close, Grissom and Young ran through the retrofire checklist. With everything ready, the pilot fired the pyrotechnics that separated the adapter from the re-entry module, giving the two spacemen their biggest jolt so far. He then armed the automatic retrofire switch. One after the other, the four rockets exploded into life and burned themselves out. Another set of pyrotechnics cut loose the expended package as "Molly Brown" arced back toward the planet she had left four and a half hours before.

At first, re-entry seemed to match the simulator training Grissom and Young had been through, right down to the colour and pattern of the plasma sheath that surrounded the spacecraft. However, "Molly Brown" seemed to be off course. Initial readings from the computer put the calculated splashdown point more than 69 kilometres from their intended landing site. The Gemini spacecraft was designed to have enough lift to be piloted to a relatively precise landing but its aerodynamic behaviour had less real lift than theoretically predicted in wind tunnel tests. So despite Grissom's best efforts to reduce the gap, splashdown of Gemini 3 was short by about 84 kilometres.

An even bigger surprise occurred just before splashdown while the spacecraft was assuming its landing attitude. After the main parachute deployed, Gemini 3 hung vertically by its nose but prior to landing a cabin switch had to be toggled to shift the spacecraft to a two-point suspension with its nose some 35 degrees above horizontal. When Grissom hit the switch, Gemini 3 literally dropped into place, pitching both men into the windshield. The shift to the landing position was so abrupt that faceplate to Gus Grissom's helmet was broken and Young's was scratched. The jolt when they hit the water a few minutes later was mild by comparison.

Looking out his window, all Grissom saw was water even though the Gemini spacecraft was designed to float. He soon realized that the main parachute was being pulled by the wind, dragging the nose of the spacecraft down. With a deliberate and steady hand, Grissom released the chute. The unsinkable "Molly Brown" righted herself, bobbing to the surface fully watertight.

The original mission plan required the crew to remain on board until the spacecraft was picked up. However, the recovery ship, the aircraft carrier Intrepid, was about 110 kilometres away so Grissom requested a helicopter pick them up and take them to the carrier. With memories of the ill-fated Liberty Bell 7, Grissom refused to open the hatch until Navy divers had attached a flotation collar to "Molly Brown." He was not going to lose another spacecraft so he and Young endured an additional 30 minutes while the divers worked. Not only was it becoming hotter inside the sealed spacecraft but it was being buffeted and tossed about by the long Atlantic swells. "That was no boat," recalled Young. Although Young managed to keep his breakfast down, Grissom was not as fortunate becoming a casualty of the heat and pitching waves. Once the hatch was open, they wasted little time getting out and into the "horse collar" that hoisted them into the awaiting helicopter.

All primary objectives were achieved except the controlled re-entry objective was only partially achieved. The angle of attack during re-entry was lower than expected. Secondary objectives were only partially achieved. The personal hygiene system was only partially tested, Operating mechanism failed on S-2 - Synergistic Effect of Zero Gravity on Sea Urchin Eggs Experiment and the photographic coverage objective was only partially successful because of an improper lens setting on the 16mm camera.