Chapter 14

Charting New Space Lanes

In October 1965, Elliot See and Charles A. Bassett II learned that they would fly Gemini IX. Chief Astronaut Donald Slayton also told them that their backups would be Thomas Stafford and Eugene Cernan.¹ Stafford was, at that time, copilot for Gemini VI. When that mission failed to go and plans brewed for VI-A to rendezvous with VII, See, Bassett, and Cernan wondered whether Stafford could finish in time to get ready for IX.

But they could not wait for him; the three men started training in November, sandwiching their simulations between those of other crews. They followed Spacecraft 9 through its building and testing, familiarized themselves with Gemini systems, and helped shape a tentative flight plan. Bassett and Cernan focused on extravehicular activities because one of them would go outside the spacecraft and ride the Air Force’s Astronaut Maneuvering Unit (AMU).

The trio interrupted their routine early in December to work as communicators in the Houston Mission Control Center during the VII/VI-A mission. They then returned to flight training. Stafford, however, had to go through his postmission debriefing before he joined them in February 1966.²

Tragedy

One bright winter morning, the last day of February 1966, the Gemini IX foursome checked into Ellington Air Force Base, Texas, for flight clearance to St. Louis in two dual-seat T-38 jet aircraft. They planned to spend several days practicing on the rendezvous simulator at the McDonnell plant.

At Ellington, the four fliers learned that weather in St. Louis was gloomy: 180-meter overcast, visibility 3 kilometers, rain, and fog, with little change expected. Instrument flight rules would be required. See called the St. Louis air traffic controllers, saying he would see them in a couple of hours. He and Cernan discussed the different runways at Lambert Field in St. Louis. See then climbed into the front seat of one T-38, with Bassett easing into the back seat. Stafford and Cernan got into the other plane. They took off from Ellington at 7:35 a.m. See and Bassett led, with Stafford and Cernan flying wing position.³

Reaching St. Louis just before 9 o’clock, See radioed the Lambert Field control tower and learned that the overcast had lifted to 240 meters since his earlier call, but the visibility had dropped to 2.4 kilometers. Light snow flurries now mixed with the rain and fog. As the aircraft descended through the overcast, the pilots found themselves too far down the runway to land. See elected to keep the field in sight and he circled to the left underneath the cloud cover. Stafford followed a missed approach procedure and climbed straight ahead into the soup to 600 meters, intending to make another instrument approach. He landed safely on his next attempt.⁴

Meanwhile, See had continued his left turn. The aircraft angled toward McDonnell Building 101, where technicians were working on the very spacecraft See and Bassett were scheduled to fly. Apparently recognizing that his sink rate was too high, See cut in his afterburners and attempted a sharp right turn; but it was too late. The aircraft struck the roof of the building and crashed into a courtyard. Both pilots were killed.⁵

NASA named a seven-man board to investigate the accident. Led by Astronaut Alan B. Shepard, Jr.,* the board looked into all aspects of the tragedy - aircraft maintenance, pilot experience, medical histories, and weather conditions. Shepard’s group listened to testimony from everyone who had anything to say, sifted the wreckage for clues, and drew conclusions. They found nothing wrong with the aircraft; it had functioned properly to the moment of impact. Within the past six months, See and Bassett had renewed their instrument flying certificates. Before and during the flight, both men had been in good physical and mental condition, as attested by medical examinations and by reported pre- and in-flight conversations. Furthermore, See was reputed to be an excellent test pilot. Careful, judicious, and technically competent, he should never have crashed at all. Weather appeared to have been the major contributing cause, and pilot error prompted by a desire not to lose sight of the field had carried them too low.⁶

On Wednesday, 2 March 1966, Spacecraft No. 9, on its way to the flight dock for shipment to Cape Kennedy, passed an American flag flying at half-mast at the McDonnell plant. The next day, Elliot See and Charles Bassett, attended by their fellow astronauts, were buried in Arlington National Cemetery across the Potomac from the Nation’s capital.⁷

NASA assigned the Gemini IX prime crew positions to Stafford and Cernan, marking the first time in the agency’s manned space flight history that a backup crew had taken over a mission.** On 21 March James Lovell and Edwin Aldrin were given the backup duties. There would be no delay in the launch schedule.⁸

The What and How Debates

Problems in getting ready for Gemini launches were causing fewer delays by the spring of 1966 than they had earlier. Vehicles were getting to Cape Kennedy for storage about a month before they were needed on the launch pad. The NASA-Air Force-industry launch teams had gained plenty of experience in reacting quickly to Gemini hardware problems. Merritt Preston, one of NASA’s leaders at the Cape, said later, “Habitually we got in trouble on Gemini, but it never got to us because we could always fix it.”⁹ Spacecraft 8’s thruster failure turned out to be a blessing in disguise. As the Cape workmen combed the adapter area around the thrusters on Spacecraft 9, they found a number of likely causes for the malfunction, which they attended to on the spot. Meanwhile, in St. Louis, engineers were exploring ways of dealing with the electrical short in the thruster circuit. GPO and McDonnell decided on a master switch that would cut off all power to the thrusters simultaneously. In case of trouble, the crew could check the system, circuit breaker by circuit breaker, until a short was found. The Cape team installed this switch on Spacecraft 9 with no effect on the launch schedule.¹⁰

For Gemini IX, the three major questions centered on working procedures rather than technology: tethered versus untethered extravehicular activity, rendezvous in the third spacecraft orbit, and radar versus optical tracking from the spacecraft.

Work on the Astronaut Maneuvering Unit by Chance Vought and the Air Propulsion Laboratory at Wright-Patterson Air Force Base in Ohio set the stage for the tether debates. The manually operated unit was powered by a hot gas, hydrogen peroxide. In a number of tests, the device showed it would be useful to an astronaut in controlling his attitude and keeping himself stable while he maneuvered in space. When, early in 1963, the Air Force was given a chance to place experiments in the Gemini spacecraft, the AMU was an obvious choice. It could help pilots working in space on many tasks that the Air Force was particularly interested in - maintenance, repair, resupply, crew transfer, rescue, satellite inspection, and assembly of structures. Since none of these was as yet a primary or secondary objective to NASA, the unit would fly in Gemini merely to confirm what it could do.¹¹ The tether entered the picture as a safety factor.

At first, the Air Force had in mind a 60-meter tether. But studies suggested that an astronaut might get tangled up in a weightless tether. Although this might be countered by a reel mechanism that would keep the line taut, the real question soon became whether a tether was needed at all. Could redundant or alternate systems offer the same safety provided by tying an astronaut to an orbiting spacecraft? The Air Force thought they could, and some in NASA agreed. Tether development was canceled.¹² Colonel Daniel McKee, head of the Air Force field office in Houston, pointed out that contractors, when they knew the propulsion system would be flown by astronauts not tied to the spacecraft, would be compelled to make highly reliable systems. After all, no one wanted an astronaut floating off into space. But that possibility was exactly what NASA was worried about. Warren J. North, Chief of MSC’s Flight Crew Support Division, held that tethers were a spaceman’s best friend, “especially if you have oxygen in them.”¹³

The dispute persisted, sometimes heatedly. An MSC and Air Force meeting in July 1965, to consider “EVA possibilities for Gemini 8,” included “EVA without tether.” But NASA Headquarters soon made its official position quite clear. William Schneider, Deputy Director of Mission Operations, wired MSC Gemini Manager Charles Mathews that “EVA shall be based on the use of a tether on Gemini flights thru Gemini 12.”¹⁴

McKee was not so easily discouraged. In February 1966, he was still debating the issue. McKee wanted the matter left open until Gemini XII, when the maneuvering unit was scheduled for its second flight. He prepared a position paper, pointing out that all critical systems on the AMU were backed up and that its test programs had been oriented toward free flight, because this was the unit’s ultimate purpose.¹⁵ MSC Director Robert Gilruth forwarded McKee’s case to George Mueller, chief of NASA’s manned space flight programs, who was still not convinced. Mueller insisted that all Gemini astronauts would be tethered, but even this experience might be helpful to the Air Force in future untethered flights. A new NASA position paper described spacecraft maneuvers that would maintain tether slackness to simulate free space activity. Although “prudence dictates that a tether be used at all times during Gemini extravehicular activity,” the door might still be open to untethered flights, “in the event that an operational requirement is identified which cannot be met in [any other] way.”¹⁶

The spinning flight of Gemini VIII on 16 March gave the Air Force a chance to push that door open: what might have happened had David Scott been outside and fastened to the spacecraft when it went out of control? He could have been wrapped up like a broken window shade. The Air Force suggested adding a safety disconnect device, at least, as long as NASA persisted in a tether, so a crewman could free himself if something like that happened again.

NASA officials, too, had been thinking about the plight of a crewman caught outside a whirling spacecraft. Scott said that he could have spotted the thruster problem and gotten back into the spacecraft to help Armstrong deal with it. But many in the Office of Manned Space Flight were convinced that, if spacecraft troubles arose when a pilot was outside, the best thing for him to do was to get back inside as quickly as he could. There were too many hazards connected with troubleshooting for him to try diagnosing any problem, let alone using a disconnect to discard the security of a lifeline. That ended the active debate,¹⁷ but there were still some who thought it was a good idea, one that ought to be tried in future programs.¹⁸

The second major issue on the Gemini IX mission - when to rendezvous with the target vehicle - was not so hotly pursued. Planners for Gemini VI, considering possible sources of trouble, had concluded that rendezvous should take place no sooner than the fourth orbit. This was a well researched procedure, which Walter Schirra and Stafford had demonstrated in high style. But some engineers in the Apollo Spacecraft Program Office wanted to tamper with success. Rendezvous in the first, or at least by the third, spacecraft revolution would more closely approximate lunar orbit rendezvous.¹⁹ In September 1965, mission planners began working on a tentative M=3 rendezvous (in the third spacecraft orbit) for Gemini IX and X. For the rest of the year, they worked on this new rendezvous scheme.²⁰

NASA, Air Force, and industry representatives met in Houston on 20 January 1966 to review the results of these labors. After the spacecraft had separated from the launch vehicle, the first maneuver - “IVAR” for the unwieldly “insertion velocity adjust routine” - would reduce orbital insertion errors. The crew would use the inertial guidance system to raise or lower spacecraft trajectory immediately. At the apogee of the first circuit, the crew would perform a “phase adjust,” to establish the proper phase relation between the spacecraft and the Agena. One and a half orbits later came another change, this time a triple play, to correct phase, height, and out-of-plane errors. The final maneuver was to circularize the flight path two and a quarter revolutions after insertion. This would place the spacecraft about 28 kilometers below the target and ready to start firings to catch it. The remaining maneuvers were similar to those required for a fourth-orbit rendezvous.²¹

No one doubted that this sequence would work but some saw no reason for an M=3 at all. Two camps formed. One group insisted that it closely approximated lunar orbit rendezvous; the other maintained that the kinship was so slight that it was not worth doing. The second group also contended that ground tracking and ground computer capabilities for this approach were not as good as they were for rendezvous in the fourth revolution. Schneider believed that the third-circuit concept would be useful to Apollo operations. Mueller agreed with him, and that settled the issue.²²

The third Gemini IX debate, radar versus optical tracking, grew from a type of rendezvous clearly applicable to Apollo. This matter first came up when several engineers, looking for ways to keep the spacecraft from getting too heavy, wanted to pull the radar out of both Apollo vehicles. The command module lost its radar in February 1965 when the ASPO Configuration Control Board ruled that the astronaut aboard the mother ship could use an optical sight to help rendezvous with the radar-and-flashing-light equipped lunar module. Later that year, with weight reduction becoming even more pressing, the lunar module’s radar was the candidate for removal. This meant that during lunar operations - whether on takeoff from the Moon or at any time the two vehicles were apart - rendezvous of the two ships would depend entirely on astronaut eyes, optical sights, flashing lights, and computers. This was too much for the men who had to fly the machines; they did not entirely trust their eyes or the suggested equipment. They wanted the help of electronic radar signals on one vehicle bouncing back from the transponder of the other. At least, they said, the radar should remain on the lunar module.²³

Stafford and Cernan did agree to include a test on Gemini IX to compare optics and radar by performing a rendezvous from above the target vehicle. In this exercise, the Agena would be over the Sahara Desert, which would simulate the lunar surface, and the crew would try to fly down to it, using both radar and optics.²⁴

Preparations for Gemini IX

When Stafford and Cernan returned to training in mid-March 1966, after the See-Bassett accident investigation, the command pilot spent little time on the spacecraft systems. After all, he had put in more than 300 hours in the spacecraft simulator in the past two years. He concentrated instead on flight planning, which was more complicated for this mission than either of the two he had worked on before. It was also subject to more changes. Cernan and Aldrin, on the other hand, had to focus on extravehicular training, which was dominated by the scheduled use of the maneuvering unit.²⁵

Working up the flight plan, with its heavy emphasis on rendezvous and extravehicular activity, began in 1965 and lasted until Gemini IX was launched. By January 1966, three types of rendezvous had been included: third spacecraft orbit, from above the target vehicle, and a very high altitude maneuver to reach an imaginary (or phantom) target. The phantom rendezvous (which depended on the Agena’s propulsion system) was soon canceled by the planners, both because they still did not completely trust the target vehicle’s engines and because they did not want to expose the crew to too much radiation.²⁶

Gemini IX soon picked up a third rendezvous, anyway, one that Gemini VIII missed doing - re-rendezvous from an equiperiod orbit. The spacecraft thrusters were used for an upward velocity change to separate it from the target. If the firing were precise and all conditions were right, the spacecraft and Agena would automatically rendezvous at the end of an orbit, because the more elliptical spacecraft orbital path would intersect the circular orbit of the target at the proper point. Theoretically, the closing maneuvers should involve only braking the spacecraft to reachieve stationkeeping (alias re-rendezvous) with the target.

Stafford was beginning to worry about doing three rendezvous; his spacecraft was the last to have the smaller tanks - 150 kilograms as opposed to (on Spacecraft 10) 208 kilograms of maneuvering fuel. But the equiperiod rendezvous was designed as a fuel-cheap way to evaluate maneuvers and lighting conditions for a dual rendezvous with a passive target scheduled for Gemini X. And Mathews decided that the lunar module abort rendezvous could remain in the flight plan for Gemini IX, but it would have a lower priority and would be contingent on fuel and time.²⁷

So rendezvous was the first major objective on Gemini IX, and preparing for the different types produced its share of headaches. But the second most important activity, extravehicular work with the AMU, was a bigger source of trouble.²⁸

The AMU had been ticketed for at least two flights from the start. This backpack, with its oxygen supply and radio, was powered by hydrogen peroxide, a relatively unstable chemical. Several MSC engineers were unhappy about using it. Warren North was one of them; North also worried about the high-temperature jet hitting the astronaut’s space suit. Cernan’s personalized jet-pack weighed 76 kilograms and its 10.2 newton (2.3-pound) thrusters operated in pairs - forward and back, up and down, but not from side to side. This caused another worry.²⁹ But Aldrin, on a training trip to California, suddenly got an idea. He tested it on his next trip to the Ling-Temco-Vought (formerly Chance Vought) plant in Dallas. After he mounted the training machine, a burst from the two aft thrusters sent him across the air-bearing table toward his target. A brief nudge from the small control jets at one shoulder and knee turned him to the side. He could now use his forward- or backward-firing thrusters to move sideways with respect to his path toward the goal.³⁰ North’s fears that the heat of the AMU thrusters might damage the pressure suit proved valid, and its insulation had to be changed. The Mylar insulation was replaced by 11 layers of aluminized H-film (a thin sheet of polyamide with a coating of aluminum on one side).³¹

The spacecraft also needed some rework to fit it for extravehicular tasks. At NASA’s request, McDonnell bonded 80 Velcro hook patches to the surface of the spacecraft. Then Velcro pads, which would cling to the patches on the spacecraft, were added to Cernan’s gloves to help hold him in place as he moved about. With body position so important in checking out and donning the AMU, two handholds and a footbar were installed as restraints. Velcro pile on the footbar would mate with Velcro patches on Cernan’s boots. During zero-g flights, he found this was not enough. After stirrups were added, he and Aldrin had no difficulty in checking out the unit in further practice flights.³²

Attempted Launches

Everything was ready for Gemini IX on 17 May 1966. In the Mission Control Center, Eugene Kranz assumed his duties as flight director, presiding over a three-shift operation. The other two flight directors were Glynn S. Lunney and Clifford Charlesworth. Only 200 newsmen were on hand, compared to the thousand or more who had covered Gemini IV the year before.³³ Gemini was becoming more routine, hence less newsworthy.

After a smooth countdown, Atlas launch vehicle 5303 rose from pad 14 at 10:12 a.m. For two minutes the rocket’s three engines rammed Agena 5004 skyward. Only ten seconds before the two outboard engines were supposed to stop, however, one of them gimbaled and locked in a hardover pitchdown position. The whole combination - Atlas and Agena - flipped over into a nosedive and headed like a runaway torpedo back toward Cape Kennedy.³⁴

Shortly after the booster engines stopped firing, the guidance control officer reported he had lost touch with the launch vehicle. Richard W. Keehn, General Dynamics program manager for the Gemini Atlas, was alarmed and puzzled. Telemetry showed that the sustainer engine had cut off, and a signal that the Agena had separated from its launch vehicle followed. Agena signals kept coming until 456 seconds after launch - then there was silence. Keehn raced over to Hangar J, the General Dynamics data station, where the telemetry tapes pointed to an Atlas engine problem. But television reports implied that the target vehicle was in trouble again, and Lockheed officials winced whenever they heard someone speak of the “Agena bird"; this was ironic in the light of the problems and delays caused by Atlas in the Mercury program and the success of Agena in Project Surefire and Gemini VIII. Meanwhile, the Gemini IX Atlas and Agena had plunged into the Atlantic Ocean 198 kilometers from where they had started.³⁵

As contractors worried about technical problems, NASA again faced the necessity for a quick recovery plan when a target vehicle failed to reach orbit. This time, however, the agency had something in the hangar, an alternate vehicle - the ATDA. After the Agena exploded in October 1965, NASA had ordered General Dynamics/Convair to be prepared to furnish a backup Atlas within 14 days of another such catastrophe.³⁶ And in April 1966, just a month before the attempted launch of Gemini IX, Schneider had reminded Preston that he would have to be ready to launch the alternate target in a hurry if the Agena again failed to keep its orbital appointment. Now it had. On 18 May, Mathews wired Colonel John Hudson, Deputy Commander for Launch Vehicles, Air Force Space Systems Division, to prepare Atlas 5304 for launch on 31 May in a mission now called Gemini IX-A.³⁷

With what had been the backup plan now in effect, the next question was what to do if the ATDA, too, failed. At a staff meeting on 18 May, Mathews announced that Gemini IX-A would be launched anyway, to rendezvous with the Gemini VIII Agena, still in orbit. McDonnell, in any case, was confident of the ATDA. When Mathews asked, in a management meeting in St. Louis the next day, “Does anyone have any reservations about flying the ATDA?” the answer was no.³⁸ That was just as well, because the motion of a rendezvous with the old Agena soon had to be abandoned. Its orbit had not decayed to the expected extent, and it was still sailing around Earth 402 kilometers up. Without the help of Agena, high-altitude flight might take too much spacecraft fuel and leave the crew stranded with no way to get to the lower orbit needed for retrofire.³⁹ Deputy Administrator Robert Seamans and Mueller agreed with Mathews that rendezvous with Agena 8 was too risky, but Gemini IX-A would still fly, even if the substitute target did not make it. Extravehicular activity with the AMU was a much needed venture in its own right.⁴⁰

Long before these decisions were made, the Atlas contractors were frantically busy. Keehn had bundled up the telemetry tapes and headed for San Diego, where study of the data plus some tests located the trouble in the electrical wiring.⁴¹ Within a week, Keehn and his group pinpointed the cause of the failure: a pinched wire in the autopilot that produced a short circuit. This meant some extra work on the electrical connectors, and General Dynamics asked NASA for an extra day to complete the task and prepare Atlas 5304 for launch. The agency set 1 June as the new date.⁴²

Although General Dynamics had accepted the blame for the mission failure, Lockheed was worried about telemetry signals that indicated a problem with an Agena inverter. A nagging question persisted. Could the target vehicle have gone into orbit if the Atlas had worked? This inverter provided power to both the gyroscope and the sequence timer. To Lockheed’s relief, a series of row cameras located at Melbourne Beach, Florida, got pictures of the Atlas’ outside loop. They showed that the Agena passed through ionized gases from the booster’s exhaust, which caused an electrical short and failure of the inverter.⁴³

On 1 June 1966, men and machines were again gathered at the Cape Kennedy launch site, this time to try to send the alternate target vehicle and Gemini IX-A into coordinated orbital flight. At the appointed time, 10:00 a.m., the Atlas rose from pad 14. After a six-minute boosted phase, it tossed the ATDA into a nearly perfect 298-kilometer orbit. Just one thing marred the picture: telemetry signals suggested that the launch shroud covering the docking port had only partially opened and had failed to jettison.

Concurrently, over on pad 19, Stafford and Cernan were going through their countdown to launch. When the count reached the three-minute mark, a hold was called so the spacecraft could be launched precisely on time for the best catchup trajectory with its target. Almost immediately after the count resumed, problems developed in the Cape ground launch control equipment when it tried to send the spacecraft refined information on the exact launch azimuth. The launch window (only 40 seconds long) closed, and Mission Director Schneider delayed the flight for 48 hours. For the second time, Stafford and Cernan had to take the elevator down. Stafford later said, “Frank [Borman] and Jim [Lovell] may have more flight time, but nobody had more pad time in Gemini than I did!” By the time Gemini IX-A lifted off, he had been in the two spacecraft (6 and 9) ready for launch a total of six times.⁴⁴

An Angry Alligator

Stafford and Cernan met with no untoward incidents on 3 June. The flight began precisely at 8:39:50 a.m. Stafford watched the instruments more closely than had his predecessors, since he had this new IVAR (insertion error correction) to handle in starting the rendezvous sequence. Six minutes after launch, CapCom Neil Armstrong said, “You are go for IVAR.” Seconds later, the command pilot fired the spacecraft thrusters in the chase toward the target vehicle 1,060 kilometers ahead.⁴⁵

By the time Stafford and Cernan arrived over the Canary Islands - only 17 minutes after launch - the computers had ground out the figures. Armstrong gave the crew the data for the phase adjustment near the first apogee. At 49 minutes into the flight, the thrusters added 22.7 meters per second to spacecraft speed to raise its perigee from 160 to 232 kilometers. “I felt that one, Tom!” Cernan exclaimed.⁴⁶

During the hour before the triple play - to correct phase, height, and out-of-plane errors - the crew checked systems, went through stowage lists, took off gloves and helmets, and got cameras ready for the rendezvous. To circularize the flight path, at 2:24 hours elapsed flight time Stafford pitched the nose of the spacecraft down 40 degrees and turned it three degrees to the left of its flight path. Fifty-one seconds later, he fired the aft thrusters to add 16.2 meters per second to the vehicle’s speed. The orbit now measured 274 by 276 kilometers - 22 kilometers below and 201 kilometers behind the target vehicle and closing with it at 38 meters per second.⁴⁷

Over Tananarive, 12 minutes before Stafford had fired the thrusters, the crew got some flickers of a radar contact with their target. A range reading of 240 kilometers between the vehicles showed on the scale. George Towner and the other Westinghouse radar builders were relieved; they had worried about acquisition of a target that would wig, wag, and wobble. The Agena was a stabilized vehicle; the ATDA was not, and its radar reflectivity changed with its continually changing attitude. Within 222 kilometers, however, electronic lockon was relatively good.⁴⁸

At 3:20 hours, the crew caught sight of their goal 93 kilometers away. For some time, it flitted in and out of view on an optical sight. At 56 kilometers, it became quite clear and remained visible from then on. As he drew nearer, Stafford reported seeing flashing acquisition lights. Thinking for a moment that the shroud had jettisoned after all, he said, “All right. We’re in business.” Surely they could not have seen the running lights so clearly if the shroud were still attached. While making minor corrections, he was glad that he could see the little “shiners” so well, because moonlight, streaming through his window, almost blinded him. The Moon soon became an asset, however, as its rays reflected off the ATDA.⁴⁹

Stafford began slowing his spacecraft at 4:06 hours. During the closure period, he peered out the window, trying to see if the shroud was there or not. Then he exclaimed, “Look at that moose!” As the distance dwindled, he knew that he had been indulging in wishful thinking - “The shroud is half open on that thing!” Seconds later, Cernan remarked, “You could almost knock it off!” When the final braking was completed,the two vehicles were only 30 meters apart and in position for stationkeeping. But it did not seem likely that the spacecraft nose could slip into the mouth of the “moose” and dock.⁵⁰

The crew described the shroud in detail and wondered out loud what could be done to salvage the situation. One of Stafford’s remarks - graphic and memorable - became the trademark of the entire mission. His animal analogy switched to reptilian when he said, “It looks like an angry alligator out here rotating around.” He itched to nudge it with his spacecraft docking bar to open its yawning jaws, but Flight Director Kranz told him to control the urge.

Perhaps the most significant aspect of this incident was the close examination of an unstable body while discussing it over the air-to-ground circuit. Stafford stayed 9 to 12 meters from the target but moved to a ticklish position only centimeters away in daylight. As the ATDA rotated slowly, he rolled his spacecraft upside down to parallel the movements of this weird looking machine. His performance met, in effect, one of the Defense Department’s objectives for the AMU - finding and inspecting unidentified satellites. Stafford said he could plainly see that the explosive bolts had fired but that two neatly taped lanyards held the clam shell partially in place. These lanyard wires had high tensile strength, he was assured from the ground, so it might not be wise to nudge its jaws.⁵¹

Schneider called James McDivitt and Scott, who were in Los Angeles, and asked them to go to the Douglas plant and look at a duplicate target vehicle shroud to see if the wires could be cut or the shroud removed in any way during orbital flight. The astronauts soon reported that the wires could be clipped, but there were many sharp edges that might tear the astronaut’s suit as he worked. In the meantime, ground controllers sent signals to the target to tighten and relax the docking cone, hoping that might free the shroud. But it remained in place - there would definitely be no docking on Gemini IX-A.⁵²

The shroud episode was embarrassing, and another investigation began immediately. The solution was simple, if one recalls the old saw about too many cooks spoiling the broth. Douglas built the shroud that Lockheed, in turn, fitted to the Agena. The ATDA, however, was built by McDonnell. Before McDonnell technicians made the final installation on the ATDA at the Cape, a Douglas engineer supervised a practice run, with the exception of the final part - the lanyards that operated the electrical disconnect to the explosive bolts. For safety’s sake, these were not hooked up. Before the mission, the Douglas engineer went home to his pregnant wife. On launch day, the McDonnell crew followed procedures published by Lockheed, which had been copied from Douglas documents. The instructions said, “See blueprint,” but the Lockheed drawing was not used. The Douglas technician who normally hooked up the lanyards knew what to do with the loose ends, even without the blueprint. But he was not there, and the strangers fixing the ATDA’s shroud looked at the dangling straps, wondered what to do with them, then taped them carefully down. In orbit, Stafford photographed their neat handiwork.

As Scott Simpkinson, GPO Manager of Test Operations, later said, three good lessons were learned from this mistake: (1) simulate processes completely, (2) keep experienced people on the job, and (3) follow written procedures exactly.⁵³

Gemini IX-A now began its equiperiod rendezvous. Five hours after launch, Stafford nosed the spacecraft down 90 degrees and fired the forward thrusters for 35 seconds to increase his speed by 6 meters per second. The crew quickly found that the target was disappearing below them. Later, in the darkness, they plotted their position with a sextant and checked the result against a preplanned chart solution. Mission planning had been right; all that was necessary to complete the rendezvous was to slow the spacecraft down. At 6:15 hours, Stafford began a series of four maneuvers to bring the spacecraft back to stationkeeping alongside the target. The second of the three rendezvous exercises was easy.⁵⁴

Less than an hour after Gemini IX-A returned to its target (6:36 hours elapsed time), the crew got ready to leave again, for the third planned rendezvous.⁵⁵ At 7:15 hours, Stafford fired the aft thrusters to decrease the spacecraft speed by 1.1 meters per second and widen the distance between the two satellites.

Stafford and Cernan could now relax a little. It had been an exhausting day. Still wanting to snap the alligator’s jaws off, they chatted with ground controllers about the shroud. Then they checked spacecraft systems, ate, and tried to sleep. Cabin noises and lights made sleeping difficult, however, and they only dozed for 40 minutes or so at a time; their scheduled eight hours of slumber were fitful, at best.⁵⁶

The next day - 4 June - Spacecraft 9 led its target by 111 kilometers. That retrograde maneuver (against the direction of the flight path) had lowered the orbit of the spacecraft (it now measured 289 by 296 kilometers) and the target traveled a nearly constant 298 kilometers above the planet. Thus the spacecraft, being nearer Earth, illustrated the paradox of slowing down to go faster, relative to the surface of the world, than the object flying overhead. The stage was set for Stafford and Cernan to do a rendezvous from above; but they first had to accelerate the spacecraft in the direction of the flight path so it would leap to a higher altitude than the target. Automatically, then, the lower flying target would reduce the spacecraft’s 110-kilometer lead. To rendezvous, the crew only had to cancel out altitude and velocity vectors that had placed their vehicle above and ahead of its objective.⁵⁷

A phase adjustment at 18:23 hours was followed a little more than 30 minutes later by a height adjustment. Another burst from the thrusters put the spacecraft into an orbit measuring 307 by 309 kilometers. The slant range to the target, which had stretched to 155 kilometers, began to shorten. Within 15 minutes, Stafford reported that the vehicles were only 100 kilometers apart. Forty minutes later, Cernan called out a 37-kilometer mark. At 21:02, the distance was 28.6 kilometers. Stafford pointed the nose of his spacecraft down 19 degrees and yawed it to the left 180 degrees, aiming at the other vehicle, which was still below and behind him.⁵⁸

Over the Atlantic Ocean, then the Sahara Desert, on past the African continent, Stafford and Cernan had troubled spotting the target, but the electronic eye of the radar did not. When they were 37 kilometers away, they had seen the vehicle reflected brightly in the moonlight and, later, in the sunlight. As the Sun rose, however, they lost sight of it completely. The range had closed to less than six kilometers before Stafford saw what looked to him “like a pencil dot on a sheet paper.” Without the radar, he said, they would “have blown that rendezvous.” But at 21 hours and 42 minutes after launch, IX-A and the target were again side by side. Three types of rendezvous had been completed in less than 24 hours.⁵⁹

At the end of the third rendezvous, the Carnarvon, Australia, flight controller told Cernan that Flight Director Charlesworth wanted the crew to start getting ready for EVA. Stafford had begun to worry about the amount of fuel that would be consumed if he continued stationkeeping with the target. Unless the flight controllers thought Cernan might actually do something about the shroud, the command pilot wanted to get out of the vicinity of the ATDA before the pilot got out of the spacecraft. The crew was also pretty tired. As they approached Houston, Armstrong told Stafford to postpone EVA until the third day and to leave the ATDA. Stafford accelerated the spacecraft by one meter per second and moved away forever from the angry alligator.⁶⁰

On 5 June, at 5:30 a.m., nearly 45 hours and 30 minutes into the mission, the crew began preparations for Cernan to emerge from the spacecraft. In the cramped cabin, they worked, rested, and worked again, finishing ten minutes before sunset. Near sunrise, Cernan cracked his hatch. It took more effort than he expected, but he soon stood in the opening, looking out at infinity and waiting for the first signs of daylight. Cernan had no feeling of disorientation nor any sensation of being lost in the dark of space. He heaved out a litter bag, the start of an exercise scheduled to last 167 minutes, during which the pilot would stand, walk, float, or ride nearly twice around the world.⁶¹

Once outside the spacecraft, Cernan did some simple experiments to get the feeling of working in space. He was startled to find that everything took longer than he had assumed it would from his experience in simulations. Cernan said he really had no idea how to work in slow motion at orbital speeds. Every movement of an arm or leg in free space exacted a reaction from his body.Minute forces that would scarcely be noticed in Earth’s gravity upset his equilibrium in space. He had only to twitch his fingers to set his body in motion. On Gemini IV, White had commented on the need for handholds. Now Cernan found that even those installed on Spacecraft 9 were inadequate and that the Velcro was not strong enough to keep his body in position as he edged back toward the adapter. He had to fight the limited mobility of his space suit, and the effort taxed his strength. He constantly referred to the umbilical as the “snake.” When he let it out to any distance, it was hard to control.⁶²

When he finally reached the adapter, some lights that had been installed especially to help him see were not burning. He asked Stafford to turn them on, but only one lit up. Moving around the adapter was no easier than moving around the rest of the spacecraft. Still, he began preparing the maneuvering unit for flight. He attached penlights; opened and checked the nitrogen and oxygen shutoff valves; positioned the sidearm controllers, umbilicals, and restraint harness; attached the AMU tether; turned on the unit’s electrical power; and changed over to the electrical umbilical. Everything, just everything, took much longer than he had expected. He kept floating out of control; he simply could not maintain body position. The few footbars, stirrups, and handbars were insufficient for any task that required leverage.

Ten minutes after sunset, Cernan’s faceplate began to fog,* so he rested. But here there could be no such thing as complete relaxation because of the tendency to drift away. He went back to work, but his visor soon fogged again. After the next sunrise, the moisture lessened. As soon as he moved about, it returned. Strangely, he felt neither hot nor cold** - his only problems were this fogged visor and tasks that had to be done with one hand when he really needed two.

When 80 percent of his work was finished, Cernan again had to stop and rest. Like a mountain climber with a backpack, he sat down in the maneuvering unit and found his most peaceful moment in this strange environment. Body molded to the seat, feet against a footbar, and arms atop the handbars, he enjoyed a taste of comfort for the first time since he started this stroll outside. The flight passed into darkness, but by the light in the adapter Cernan could tell just how occluded his faceplate had become.

He began to wonder whether to go on with EVA. Mentally, he ticked off the checklist items that remained: strap in, change to the AMU oxygen lead, start breathing oxygen from the unit’s supply, and free his personal transportation from the spacecraft adapter. Cernan knew, from repeated experience in zero-g training flights, that he could do these tasks blindfolded. But then what? he thought. “So you make the connections . . . if you can’t see, you can’t very well go out there and fly because you don’t know what to expect.” And if he flew the maneuvering unit, anyway? He could finish putting it on, he knew, because he was restrained in the adapter. But when the time came to take it off, he would be standing in free space. Could he take it off with one hand, while holding onto the spacecraft with the other? Would it be wise to try that when he couldn’t see? Much better to end the exercise now, he thought. So he and Stafford decided to cancel the rest of the EVA, and Mission Control agreed.

Carefully, Cernan eased himself out of his comfortable seat, leaving his sun visor up to see if that might help defog his faceplate. At sunrise, he detached the AMU’s electrical umbilical and connected his spacecraft lifeline. Still almost blind, he groped his way out of the adapter and back along the spacecraft to the cockpit. He slid into the hatch and stood there a few moments. Stafford held on to Cernan’s legs so he could rest. Slowly his faceplate began to clear in the center, giving him a narrow range of vision. He tried to retrieve an externally mounted mirror that the command pilot had used to watch what was going on behind the cockpit. As Cernan wrestled with the mirror, his suit’s cooling system became overtaxed, causing him to get extremely hot for the first time. His faceplate again fogged up completely. Stafford helped Cernan in and, together, they closed the hatch and started pressurizing the cabin. With their helmets almost touching, Stafford still could not see Cernan through the faceplate. The extravehicular exercise had lasted for 128 minutes instead of the planned 167; fogging had started 63 minutes after hatch opening.⁶³

Two major aims of Gemini XI-A were rendezvous and extravehicular activity; the third was experiments.*** Stafford and Cernan gave closer attention over a sustained period of time to the assigned experiments than had any Gemini crew before. When the space walk was postponed to the third day, the astronauts spent most of the second day on experiments and rest. About the only conversation they would tolerate from the ground was about their workload. On several occasions, when flight controllers forgot, they were reminded that the crew was busy. “My mistake for contacting you,” came the response.⁶⁴

Stafford and Cernan carried out M-5, bioassay of body fluids (the only medical experiment), which required wastes to be collected and labeled in laboratory fashion. Like other Gemini crews, Stafford and Cernan disliked this complex and messy task, nor did they enjoy the blood sampling they had to endure before and after the mission. Stafford equated the physical effort for M-5 to that required for doing a rendezvous and a half.⁶⁵

The Department of Defense sponsored one experiment in addition to the Astronaut Maneuvering Unit - D-14, UHF/VHF polarization - to measure the inconsistencies of the electron field along the spacecraft orbital path and to study structures and variations of the lower ionospheric region. Stafford and Cernan operated the D-14 transmitter five times over Hawaii and once over Antigua during five successive revolutions. Everything worked well, but the number of measurements was limited because the antenna was poorly located. Later, when he was struggling outside, Cernan accidentally broke off the D-14 antenna.⁶⁶

The four remaining experiments were scientific. Two of these involved micrometeorite collection. S-10 was a package mounted on the ATDA for Cernan to pick off during his space walk. This he could not do, but the astronauts did manage to photograph the package. The pictures showed that the device was in excellent condition. The second experiment of this type, S-12, was attached to the spacecraft and operated by the astronauts by remote control. While Cernan was in the adapter, he heard Stafford close and lock the box. Cernan retrieved the package and stowed it in the spacecraft.⁶⁷

Cameras were the principal instruments used in the last two experiments - S-1, zodiacal light photography, and S-11, airglow horizon photography. Stafford and Cernan took S-11 pictures on three successive night passes, between the 29th and 33rd hours of flight. They got 45 good photographs, under very trying circumstances. The tendency to float upward in zero gravity made pointing the camera and taking the pictures no easy task.

Zodiacal light photography had been scheduled for the space walk. A fogged faceplate, however, was no help in aiming a camera. The pictures had to be taken from inside the spacecraft after Cernan had returned to the more restful confines of his couch. Cernan had to hold the camera against his chest while pointing it out the window at the targets and calling out directions to Stafford for aligning the spacecraft. He obtained 17 good photographs.⁶⁸

On 6 June, during the 45th revolution, they got ready to come home. Gemini IX-A touched down 0.70 kilometers from the planned impact point in the Atlantic Ocean, 72 hours, 20 minutes, and 50 seconds after launch. After scanning the panels in the spacecraft and flipping some switches, the crewmen opened both hatches, relaxed, and watched the gently rolling sea. They were close enough to raise their arms and thumb a ride on the Wasp. Stafford and Cernan stayed in their spacecraft until it was hoisted onto the ship’s deck. After the usual hullabaloo had subsided, Cernan told anyone who would listen to him that extravehicular activity was not easy, not nearly as easy as people believed. And he seemed bitterly disappointed that he had been unable to fly the Air Force’s maneuvering unit.⁶⁹

To the public, the frustrations of Gemini XI-A - the formidable shroud and the fogged faceplate - overshadowed its accomplishments. Flying formation with and examining an unstable body had been a useful experience. Of even more significance were the advanced rendezvous maneuvers, proving that the flight controller and crews could handle sophisticated rendezvous techniques that might be applicable to Apollo. Had Gemini IX-A been VIII, the results might have been viewed differently - as just part of the learning process. But docking, a primary objective, had not been achieved; and extravehicular activity had not succeeded in evaluating the maneuvering unit. Some engineers in MSC Crew Systems Division thought too much was being tried too soon - the simpler maneuvering unit planned for Gemini VIII would have been the logical second step in mastering EVA. As it turned out, the cliche to “watch out for that second step” would have made a good motto, but the step was greater than anyone had yet realized.⁷⁰

Laying New Tracks

Immediately after Gemini IX-A, Deputy Administrator Seamans expressed his dissatisfaction with results and the way missions were being handled. Although the flight, ground, and operations crews performed well in what they did, the achievements fell too far short of mission objectives. Seamans wanted a mission review board set up. He ticked off several items for such a group to study: corrective measures for the Atlas-Agena failure, the guidance update problem that delayed the launch two days, the shroud incident, and the suit environmental control difficulties. He also wanted the board to make sure that objectives and alternatives were carefully selected well in advance of launch.⁷¹ Mueller established the Gemini Mission Review Board, with his deputy, James C. Elms, as chairman.⁷² *

The board first laid out ground rules for drafting recommendations for each of the remaining Gemini missions. Benefits for Apollo and for science and technology were weighed against risks to crew safety. Mission planning policies were examined - was too much being programmed or too little?⁷³ With Gemini X scheduled for 18 July, planning for that flight was nearly firm. The board did measure mission objectives against the new ground rules, but there was neither time nor opportunity for more than minor changes.⁷⁴

Gemini X, like VIII and IX, was a complex flight with multiple objectives. Among these was a dual rendezvous involving two Agenas - one launched for the mission, the other a passive target left over from Gemini VIII. Using the target’s main engine to propel the docked Agena/spacecraft combination to high altitudes had been hotly debated on two previous missions. When the Atlas dropped into the Atlantic Ocean on 17 May 1966, the time for discussion was past. Since neither Gemini VIII nor IX-A had provided the hoped-for experience of firing the Agena’s main engine while it was docked to a spacecraft, a decision had to be made promptly. There were only three flights left in the program. Nor would there be any preliminary, low-level practice first. The next day, Mathews told his staff that Gemini X would dock with Agena 10 and together they would climb to Agena 8.⁷⁵

On 24 January 1966, John Young and Michael Collins were named to fly Gemini X.** When Young first heard about the dual rendezvous plan, he thought, “they must be out of their minds.” The astronaut had two worries. Could he slow down the linked vehicles and stop them in time to keep from crashing into the second Agena? VIII’s Agena, having run out of electrical power, was dead, with no radar transponder or other apparatus to help in the search. Could he even find the old Agena, using only optical equipment? Young recalled, “We hadn’t worked on any of these procedures. The problem with an optical rendezvous is that you can’t tell how far away you are from the target. With the kind of velocities we were talking about, you couldn’t really tell at certain ranges whether you were opening or closing.”⁷⁶

Young also remarked, “We didn’t have an EVA program,” but that soon changed. Collins would do experiments, retrieve packages from both the spacecraft and the passive target, test a zip gun, and visit an unstabilized vehicle. The backpack was dropped for missions X and XI and replaced by a 15-meter umbilical to supply oxygen and electrical support.⁷⁷

Deciding what to do was only the beginning; how to do it was the bigger challenge. The second part of the double rendezvous (with the passive Agena) was particularly tricky. Agena 8, like all Earth-orbital vehicles, had been precessing above and below the equator on its orbital path. With no help from the dead target possible, the Gemini X Agena and spacecraft would have to be launched at very precise times. Suppose circumstances delayed the launches? It had happened before - more often than not! The mission planners would have to come up with a new set of numbers in a hurry. With events so closely related, delay or failure at any point threatened all aims of the flight.

While shaping the Gemini X mission for the dual rendezvous, the planners decided to give the crew some helpful experience in onboard navigation using optical equipment, charts, and the spacecraft computer. The crew would join its first target in the fourth orbit. Mission sequence was the next consideration. When should the dual rendezvous take place - the second day or the third day? Mission planners eventually decided that the second day should be devoted to experiments, the third to chasing the passive target. This, in itself, appeared to create a conflict of aims; although Agena 10 was needed to carry the spacecraft to the second target, many of the planned experiments could not be performed while the vehicles were docked.

About 50 people kicked this problem around at a trajectories and orbits meeting on 28 April 1966. Obviously, the launch dates would have to be jockeyed to get the best phase relationship between the spacecraft and target for both the dual rendezvous and the experiments.⁷⁸

Even assuming that both launches went as planned, shaping the second rendezvous was an exacting task. The North American Air Defense (NORAD) Command, at Colorado Springs, had kept track of Agena 8’s whereabouts ever since it ran out of electrical power. To begin the rendezvous, the docked Gemini X/Agena 10 combination should first go into a large elliptical orbit, 298 kilometers at perigee and 752 kilometers at apogee. After six revolutions to judge phase relationships, Agena 10 would then maneuver down to an approximately 398-kilometer circular orbit near Agena 8’s space lane, as reported by NORAD.

The high altitude aspect of the flight raised its usual qualms. Although the Gemini Program Office no longer resisted the use of the big Agena engine while the vehicles were docked, McDonnell did not like the idea of the vehicles passing through so many high orbits, which might affect a safe emergency reentry if the retrorockets did not perform as needed. There was also the South Atlantic radiation zone to be considered. In a trajectories and orbits meeting at the end of June 1966, the maximum acceptable altitude for the dual rendezvous was set at 298 by 1,065 kilometers, based on radiation constraints and actual radiation levels measured in 1964. But the decision to use Agena for docked maneuvers had already been made, and any misgivings had to be laid aside. After careful study, the planners concluded that an emergency reentry from an elliptical orbit with a perigee of 298 kilometers could be made even if only three out of the four retrorockets fired. Finally, they plotted the spacecraft’s orbital track with great care, to avoid the heavy radiation patches.⁷⁹

With the memory of past flights still fresh - when no one had been sure what target, if any, would be waiting - they made alternate and contingency plans for Gemini X. If the target vehicle for this flight did not reach orbit, the mission would be renamed X-A, and the spacecraft would be launched into a 162- by 385-kilometer orbit to rendezvous with the Agena 8 on the 16th revolution. The alternate plans also covered experiments, extravehicular activity, and systems tests.⁸⁰

The Switch Engine

After the premission review, the traditional meal, and the ritualistic suiting up, Young and Collins left the crew quarters on 18 July 1966 for pad 19 - to begin the most complex manned flight so far. They had been awakened at noon for a 5:20 p.m. takeoff, when a 35-second window offered the best chance for rendezvous with the two Agenas. The Atlas lifted its payload toward space at 3:39 p.m., just two seconds late.* One hundred minutes later, the Gemini launch vehicle boosted the spacecraft skyward exactly on time. Except for a slight shaking and a buzzing in their ears, Young and Collins had a nice ride to start chasing their first target.⁸¹

At entry into orbit, Gemini X trailed its Agena by 1,800 kilometers. Flight Director Lunney told the crew they were all set for a fourth-orbit rendezvous. Collins unstowed a Kollsman sextant to sight on selected stars for an attempt at optical navigation. Young pointed the spacecraft while his crewmate tried to find the horizon. Collins realized that he was using the wrong reference when he saw stars below the line. He had been mistaking the airglow, a band of radiant light from the upper atmosphere, for the horizon. Even after he corrected this, Collins could not get the lens of the sextant to work properly, as the optical image of the stars did not agree with what he had been taught. He laid the Kollsman aside and tried an Ilon instrument, but that was little help as the Ilon had a severely limited field of view.⁸²

Young and Collins checked their figures with Lunney, who had been watching their activities carefully through telemetry. When the trio found that the numbers did not agree with those of the ground computers, Gordon Cooper, the Houston CapCom, passed the word that the crew would have to use the ground computations. Young then fired the thrusters to adjust their orbit to 265 by 272 kilometers. When he aligned the platform for the terminal phase, the command pilot did not realize that the spacecraft was turned slightly. As he thrusted toward the target, Young needed two large midcourse corrections. The spacecraft path toward the Agena was not lined up properly. So he had to stop thrusting briefly and take off on a new track. The final translational maneuvers to reach the Agena cost nearly 181 kilograms of fuel, or three times more than any earlier mission.⁸³ Five hours and 52 minutes after launch, Young reported a rigid dock.⁸⁴

Because too much fuel had been used, Lunney decided to omit docking practice - backing away and returning to the target’s cone. Young and Collins wondered if the second rendezvous might also be canceled, but, some six and a half hours into the mission, the ground controllers started giving the crew the data they would need for the burn. Then, an hour later, the CapCom at Hawaii cleared them to try for second rendezvous.

The Agena main engine roared into life exactly on time. For 80 seconds, the target vehicle thrust the spacecraft upward, adding 129 meters per second to their speed. The crew, at the moment flying backward, had little to say about their reactions to a negative one-g force (a shove to the front of the body - “eyeballs out” - rather than a push on their backsides - “eyeballs in” - as during launch). They were thrown forward from the seats against the body straps. Young later described the first ride on a space switch engine:

At first, the sensation I got was that there was a pop [in front of our eyes], then there was a big explosion and a clang. We were thrown forward in the seats. We had our shoulder harnesses fastened. Fire and sparks started coming out of the back end of that rascal. The light was something fierce, and the acceleration was pretty good. The vehicle yawed off - I don’t remember whether it was to the right or to the left - but it was the kind of response that the Lockheed people had predicted we would get. . . . The shutdown on the PPS [primary propulsion system] was just unbelievable. It was a quick jolt . . . and the tailoff . . . I never saw anything like that before, sparks and fire and smoke and lights.⁸⁵

Gemini X reached an orbit that measured 763 kilometers at the top and 294 kilometers at the bottom. The Agena had pushed the spacecraft more than 463 kilometers above its initial apogee. Young and Collins now viewed Earth from a higher elevation than any human beings ever had. Instead of gazing at the planet in wonderment, however, they confined their attention to their own little, artificial world. They watched spacecraft systems and kept an eye on the radiation dosage readings (which were within tolerable limits). During his technical debriefing, Young only reported, “We took some pictures at apogee. . . . I don’t know where it was, but it shows the curvature of the Earth. . . . We took some pictures coming down hill. I think it was the Red Sea area.” Thus, in rating one impression over the other - record high altitude versus Agena ignition - Young and Collins were more affected by the firing of the switch engine than they were by the unique vantage point they had reached. This lack of awe at their record height was caused, at least in part, by the fact that the switch engine blocked much of the downward view.⁸⁶

[Page 346 displays photos of Gemini X - 18 July 1966]

Nine hours into the flight, the pilots bedded down, sleeping fitfully. Both were still wondering if the second rendezvous would be done. Besides, neither was “really bone-tired,” Collins said. Charlesworth’s shift in Mission Control was busy that night, reviewing alternate plans for adapting the mission to fulfill its objectives.

When Young and Collins opened for business after 18 hours of flight, their spirits lifted as the CapCom at Carnarvon gave them the numbers for the next target vehicle firing. With the Agena/spacecraft combination faced about so the main engine would fire directly into the flight path, Young made a 78-second burn to reduce the velocity by 105 meters per second and lower the apogee to 382 kilometers. The pilots were again pressed forward in their seats, but this time they were impressed more by the firepower of the Agena than by its fireworks. “It may be only 1 g, but it’s the biggest 1 g we ever saw! That thing really lights into you,” Young commented.⁸⁷

Like rendezvous maneuvers in the past, the next Agena burn (and the final one with the main engine) aimed at circularizing the orbit. At 22:37 hours, the target drove the spacecraft along the flight path to add 25 meters per second to the speed. This brought the low point of the orbit up to 377.6 kilometers - only 17 kilometers below Agena 8.⁸⁸

Although rendezvous and docked maneuvers with the Agena were the high point of the first day, the crew also spent a good part of that time on the 14 experiments they carried.** Twenty minutes after launch, the crew turned on a switch to start the tri-axis magnetometer (MSC-3). This device was used, as it had been in other flights, to measure the radiation levels in the South Atlantic Anomaly. Two other experiments were also devoted to radiation - MSC-6, beta spectrometer (mounted in the adapter to measure potential radiation doses for future missions), and MSC-7, bremsstrahlung spectrometer (installed in the cabin to detect radiation flux as a function of energy when the spacecraft passed through the South Atlantic Anomaly).⁸⁹

Some of the experiments had to be done outside the spacecraft. Before the third Agena burn, Collins got ready for his first exposure to outer space, a standup EVA. Preparations went well and the hatch opened easily. At sunset, Collins stood in his seat, setting up a 70-mm general-purpose camera for S-13, a photographic study of stellar ultraviolet radiation. Collins aimed the camera at the southern Milky Way, scanning from Beta Crucis to Gamma Velorum, and exposed 22 frames. The entire night pass was devoted to this task. Young helped Collins identify the stars, at the same time controlling the spacecraft and target vehicle combination. With the beginning of daylight, Collins began MSC-8, color patch photography, to see if film could accurately reproduce colors in space. The pilot did not complete this assignment, however, as his eyes began to fill with tears. Young had the same problem. They suspected at first that the anti-fog compound inside their faceplates was irritating their eyes. They closed the hatch at 24:13 hours, about 6 minutes early.⁹⁰

They had noticed a strange odor that they thought might have been the lithium hydroxide used in the environmental control system, but ground engineers finally concluded that their smarting eyes were caused by having both suit fans on at once. They turned one fan off and, at 30 hours elapsed time, began a second sleep period. Bone-tired this time, they rested well.⁹¹

Young and Collins awakened to a “morning” of increased activity. In addition to normal systems check, the ground network also reminded them of the experiments expected this day - the S-26 ion wake measurement, to study the ion and electron structure of the spacecraft’s wake (after it undocked from the Agena), S-5 synoptic terrain, and S-6 synoptic weather photography. The pilots also had to work in two maneuvers to help them catch up with Agena 8.

Their Agena switch engine had accomplished its task, and more. After being hooked to it for 39 hours, however, they were getting a little tired of looking at it. Young said that watching the Agena out his window was

just like backing down the railroad [track] in a diesel engine looking at a big boxcar in front of you. . . . The big drawback of having the Agena up there is that you can’t see the outside world. The view out of the window with the Agena on there is just practically zilch.⁹²

On freeing themselves from their Agena, the crewmen began preparing for Collins’ exit from the spacecraft. Young now needed to make the final maneuvers to get the spacecraft close enough to the Agena 8 for Collins to reach it. Collins connected the 15-meter umbilical to his suit and then fastened it out of the way until time to use it.

"45:38. First sighting of Gemini VIII,” Young said. “At this minute it’s blurry.” After the distance between the two vehicles had been calculated, the Houston CapCom (on the remote line through the Canton station) informed Young, “Your range, Gemini X, is 95 [nautical] miles [176 kilometers].” The crew then learned that what they had been looking at was their own Agena just 5.5 kilometers away. Houston offered consolation, “95 miles is a pretty long range,” and Young answered, “You have to have real good eyesight for that.” They didn’t see the Gemini VIII Agena until it was 30 to 37 kilometers from them, looking to Young like “a dim star-like dot until the sun rose above the spacecraft nose.” NORAD’s constant care had paid off. They found Agena 8 just where it was supposed to be.⁹³

At 47:26 hours Young started the final closure, with Collins computing the figures for two midcourse corrections. The crew found the old Agena pretty stable, and Young moved in to stationkeep about 3 meters above it. In less than 30 minutes, he told the Houston CapCom that they were going down for a closer look at the micrometeorite collection package. Back in Mission Control Center, fuel usage during stationkeeping was being very closely watched. When it proved to be reasonable, Gemini X received a go for the next extravehicular exercise. “Glad you said that,” Young answered, “because Mike’s going outside right now.”⁹⁴

Collins emerged from the spacecraft at dawn. Like Cernan on Gemini IX-A, he found that all tasks took longer than he expected. But he picked off the package from the spacecraft exterior. Next, he moved to the adapter to attach his zip gun to the nitrogen fuel supply. Back in the cockpit area once again, he held on while Young moved the spacecraft to within two meters of the Agena.

Collins pushed off from the spacecraft, floated freely in space, and grasped the outer lip of the docking cone on the target. As he clutched at the experiment package, he wished for handholds - or more hands. Cernan had warned him that it would be hard, and it was. He soon lost his grip on the smooth lip and drifted away from the package and from the Agena. He had to decide quickly whether to pull on the umbilical, coiling about like a snake, or to use the hand-held gun. Being about 5 meters away from the spacecraft, Collins chose the gun. It worked, and he propelled himself first to the spacecraft and then back to the Agena, using a series of squirts to get to the package. This time he clung to wire bundles and struts behind the adapter cone and grasped the S-10 experiment. Collins was supposed to attach a replacement device in its place, but he abandoned this idea, fearing he would lose the one he had picked up. Using the umbilical, he pulled himself hand over hand back to the cockpit and gave the S-10 package to Young.

So far, the umbilical had been snubbed so it would extend only 6 meters. The pilot now unsnapped the buckle that released the remaining 9 meters, intending to evaluate the gun. But the gun play stopped before it started. The Hawaii CapCom told Young, “We don’t want you to use any more fuel [for stationkeeping].” Young replied, “Well, then, he’d better get back in.” To Collins he said, “Come on back in the house.”⁹⁵

Getting back into the spacecraft was surprisingly difficult. Collins had gotten himself tangled in the umbilical. Since the pressurized suit made it difficult to see or feel just where the line had wrapped itself about him, he had to wait while Young helped unwind him and got him back into the seat. But fuel remained the big question. Houston called them, “just . . . to confirm that you’re not using any fuel.” Young replied, “We’ve got everything shut off.”

More was shut off than he realized. He soon discovered that the radio transmitter had also been turned off. By this time, Collins was back in his seat. Young reported that hatch closing had been easy. With the long lifeline coiling all over the cabin, Young thought it made “the snakehouse at the zoo look like a Sunday school picnic.” A little over an hour later, the crew reopened the hatch and tossed out the chestpack and umbilical. This operation only took three minutes. McDonnell had done an excellent job on this righthand hatch.⁹⁶

Because of the time spent struggling with the umbilical, Collins and Young had to hurry to get set up for an important maneuver that would make the point of reentry more precise. They carried out an orbit-shaping activity exactly on time, at 51:38 hours. This retrograde firing, of 30 meters per second, brought the spacecraft perigee down 106 kilometers, making the orbital parameters safe for reentry. After another round of experiments - this time synoptic terrain and weather photographs taken as the spacecraft drifted through space - the crew began their third sleep period.⁹⁷

On awakening (about 63 hours into the flight) on homecoming day, Young and Collins spent more time on experiments and did their packing. Then, 70 hours and 10 minutes after liftoff, the crew felt the first retrorocket ignite as they passed over the Canton Island tracking station during their 43rd revolution. Reentry went remarkably well, with Young steering bank angles by computer solutions. Landing in the western Atlantic at 70:46 hours (4:07 p.m., 21 July 1966) was only 5.4 kilometers from the aiming point. The crew of the primary vessel, the Guadalcanal, watched the spacecraft hit the water. Once the swimmers had attached the flotation collar and positioned the raft, Young and Collins climbed out. They were lifted by helicopter to the deck of the recovery ship.⁹⁸

With that part of the mission completed, the flight controllers put the Gemini X Agena through its paces. Over a 12-hour period, the main engine was fired twice and the small engine once. Since the first maneuver was intended to study temperatures at higher altitudes, the controllers sent the Agena up to a 1,390- by 385-kilometer orbit. They watched it for almost seven hours and found that the temperatures varied little from those at lower orbits. The vehicle was then returned to a circular orbit (352 kilometers) that would make it available as an alternate target for later flights.⁹⁹

Gemini IX-A and X had successfully grappled with some of the specific needs of the Apollo program, acquiring operational experience while fostering healthy debates between the two programs on procedures and equipment. Perhaps the greatest benefit to Apollo was the demonstration and practice of several types of rendezvous. Each provided a storehouse of information. In addition, the orbit-shaping maneuvers to the higher altitudes established that the trapped-radiation hazards could be avoided on trips into deep space. Then, too, the very fact that one spaceborne vehicle could meet another, latch onto it, and use it as a kind of space tug offered many possibilities for such space flight concepts as shuttles, space stations, and space laboratories.

There had been problems, but missions IX-A and X had logged a combined total of three hours and 41 minutes open-hatch experience. Although the extravehicular hiatus between the fourth and ninth flights adversely affected both equipment and operational development, Cernan and Collins had shown that tasks outside the spacecraft were feasible. They found that all chores took longer than foreseen and that body positioning was difficult. During technical debriefings, each extravehicular pilot had pointed out the need for more and better restraints and handholds. These aids were being developed. Overall, perhaps, extravehicular activity remained Gemini’s greatest problem. It was and is dangerous, difficult, and deceptive, despite its delights.

The ninth and tenth flights also took several steps forward in experiment performance. Despite operational constraints, usually brought on by limited fuel resources, each situation had been modified to wring the utmost from specific experiments. More and more, principal investigators were being brought in to help with modifications and to assist in rescheduling their tasks for later in the missions, if necessary. These realtime flight changes could not have been carried out in an unmanned flight and would not have been done in an earlier Gemini mission. So, in Gemini IX-A and X, the experiments program began to achieve maturity.

By the end of Gemini X, many of the men and women who had worked full time on the program had begun to have a strong feeling of anticlimax and to wonder about their next jobs. Some had already gone on to other fields, but Mathews tried to control this exodus and to hold enough together to finish the flights. Shortly after IX-A, he told his staff that the Gemini Program Office, as such, would not be continued. The people would be absorbed into other MSC activities - mainly Apollo and Apollo Applications. By early August, a personnel placement committee*** had begun work. It soon arranged four to six interviews for each of the 193 project office people. This allayed any immediate fears, but Mathews still warned his staff to refrain from making personal contacts for new jobs until the committee could complete its arrangements.¹⁰⁰ There were two more flights in the Gemini program, but it already seemed to be heading into history.