CREWLESS SUCCESSES

By late 1963, two unmanned Gemini missions, instead of one, had been timetabled before a crew would be flown. The main focus for the so-called ‘Gemini-Titan 1’ was to evaluate the performance of the spacecraft and rocket, and the capsule itself carried dummy equipment and ballast to match the weight and centre-of-gravity constraints of a piloted flight. Moreover, it would remain attached to the Titan throughout its mission and no plans were made for it to be recovered, so four large holes were bored into its ablative heatshield to ensure destruction during re-entry. Inside the cabin, roughly where the two pilots would sit on manned flights, a pair of pallets housed radar transponders and instruments to measure pressures, vibrations, accelerations, temperatures and structural loads. On 1 October 1963, NASA officially accepted the spacecraft from McDonnell. Three days later, Gemini 1 was shipped to Cape Canaveral for final pre-launch testing.

A flight readiness review in mid-February 1964 verified the spacecraft’s systems and on 3 March it moved to Pad 19 to await the arrival of its launch vehicle. The Titan assigned to the mission, dubbed ‘Gemini Launch Vehicle 1’ (GLV-1), had suffered numerous problems throughout the previous year, including damaged wiring caused by faulty clamps, improperly-cleaned hydraulic tubing, a malfunction­ing gyroscope and interference between several electronic components. Martin conducted a full systems acceptance test in September 1963, but GLV-1 was rejected by NASA and the Air Force’s Space Systems Division when their joint inspection found severe contamination of electrical connectors throughout the rocket. A month later, after this contamination had been corrected, Gemini 1’s launch vehicle was officially accepted and on 26 October its two stages were transported to the Martin airport and flown to the Cape.

Further problems pushed the launch from February into March and, eventually,

into April of the following year. Lack of compatibility between the Titan and its Pad 19 support systems, together with a faulty turbopump, were the prime culprits, although contaminated oxidiser and a malfunctioning propellant valve conspired to ruin a ‘wet’ countdown demonstration test on 7 January. Two weeks later, the entire sequence of fuelling, countdown, ignition and shutdown commands, guidance control and telemetry were successfully demonstrated for the individual stages, with each firing for 30 seconds. By the end of January, the two stages had been mated together and on 3 March Gemini 1 arrived at the pad for installation. Liftoff, optimistically, was scheduled just four weeks later. Problems arose during electronic – electrical interference tests, which pushed the mission to no earlier than 7 April, but all other pre-flight activities proceeded smoothly.

Eventually, mission managers agreed on 8 April for launch. One second after 11:00 am Eastern Standard Time (EST), the Titan Il’s first stage engines ignited with a low-pitched whine and the first Gemini left the pad. Two and a half minutes into the ascent, the first stage propellants were exhausted and the second stage roared to life, explosive bolts separating the two segments of the booster. By five minutes after launch, itself expended, the second stage and Gemini 1 had achieved an altitude of 160 km and were more than 1,000 km downrange of the Cape, moving at 28,080 km/ h. The combination was in orbit. So perfect was the Titan’s performance that Major – General Ben Funk of the Air Force Space Systems Division described it as ‘‘a storybook sort of flight’’.

Within five hours, as planned, its test mission was over. The capsule and second stage, whose altitude at apogee reached 300 km, were expected to remain aloft for three and a half days; they actually managed almost four, during which time the Manned Space Flight Network, controlled by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, tracked them constantly. Finally, on 12 April, three years to the day since Yuri Gagarin’s pioneering voyage, Gemini 1 re-entered the atmosphere to destruction, its last fragments splashing down in the South Atlantic. NASA commended the Air Force on its rocket and envisaged Gemini 2 by the end of August and an inaugural manned flight in mid-November.

Unluckily, the elements – first lightning, then hurricanes – delayed the second launch well into September. Additionally, delays in getting key components such as thrusters and fuel cells had placed the spacecraft’s construction behind schedule and Gemini 2 did not even commence testing until January 1964. Also, delivery of the Titan II for the mission, which had been accepted by NASA in mid-June, was postponed due to lagging work on the spacecraft. Anticipating Gemini 2’s arrival by early September, the rocket was eventually installed on Pad 19 to undergo final testing; then, in mid-August, in a severe thunderstorm, lightning struck the launch complex. No physical damage was done to the vehicle, although a number of failed parts of ground support equipment needed replacement. Even before this work had been completed, Hurricane Cleo brushed the Cape on 27 August. The Titan’s second stage had been demated and placed under cover, but the still-upright first stage bore the hurricane’s full force. Fortunately, Cleo’s effects were lower than the rocket had been designed to withstand and little serious damage was done. By 1 September, the second stage had been reinstalled.

By now, there were suggestions of replacing GLV-2 with the GLV-3 vehicle earmarked for Gemini 3, in effect ‘losing’ one mission, but the Air Force eventually persuaded NASA to stick with the original Titan. Barely two weeks after Cleo, Hurricane Dora reached the Cape, forcing engineers to again demate the two stages and get them under cover. A third hurricane, Ethel, had bypassed the launch site by 14 September and preparations could resume in earnest. Gemini 2 finally arrived in Florida on the 21st, but by this time NASA’s schedulers had officially given up on the already-slim chance of launching a crew before the year’s end. After testing, the spacecraft was mated to the Titan II on 5 November in anticipation of a launch early the following month.

Three holds characterised Gemini 2’s countdown and, as the clock hit zero at 11:41 am on 9 December, the rocket’s first stage engines ignited. Barely a second later, they were automatically shut down; the Titan had apparently lost hydraulic pressure in its primary control system and had switched to its backup, which, because the rocket had not lifted off the pad, cut off the engines. It transpired that unexpectedly high pressure in one of the hydraulic lines had burst the aluminium housing of a servo valve, allowing fluid to leak out. ‘‘It was frustrating,” wrote Deke Slayton, ‘‘but a good lesson. You couldn’t have shut down at Atlas like that. It wouldn’t have done us much good to have the Titan get off the ground, then blow up, either. So it gave us confidence in the [malfunction-detection system] which we needed a year later.’’

Steadily, the Titan’s propellants were drained and the spacecraft made safe until a replacement valve arrived in early January 1965. The second attempt to get Gemini 2 airborne was virtually flawless: despite a problem with the sluggish fuel cell, which meant it could not be used, the Titan II roared aloft at 9:03:59 am on 19 January. Its suborbital trajectory exposed the spacecraft to the most severe re-entry heating subsequent missions could be expected to experience and it plopped safely into the South Atlantic at 9:22 am. Minor glitches had not detracted from a mission which had effectively certified Gemini to carry its first human crew.