March 19
Voskhod 2 landing
March 23
Gemini 3
June 3
Gemini 4 launch
June 3
1965 EVA 2
World EVA 2
U.S. EVA 1
Duration: 0:36 Spacecraft/mission: Gemini 4 Crew: James McDivitt, Edward White Spacewalker: Edward White Purpose: Demonstrate EVA feasibility; test HHMU
"It's the saddest moment of my life," said Ed White after his commander, James McDivitt, ordered him to return to the Gemini 4 spacecraft and conclude the first U.S. EVA. White's EVA was originally scheduled to begin about 3 hr after launch, during Gemini 4's second revolution about the Earth. However, an attempt to rendezvous with the expended upper stage of Gemini 4's Titan launch vehicle proved arduous (and ultimately unsuccessful) and EVA preparation required more time than expected, so the EVA was postponed to the third revolution. After wrestling with a jammed latch and pushing back the stiff spacecraft hatch, White stood in his seat and installed a 16-mm camera outside Gemini 4 to record the EVA, becoming slightly out of breath. He then used a Hand-Held Maneuvering Unit (HHMU) to leave the spacecraft. The device permitted only 20 sec of maneuvering before exhausting its compressed oxygen supply, but the test was judged a success. White inspected Gemini 4, then evaluated his umbilical, which turned out to be useful for limiting distance, but not for more precise maneuvering. In addition to supplying oxygen, the 7.5-m (25-ft) umbilical carried communication and bioinstrumentation lines and a load-alleviating tether. The umbilical was covered by a thin layer of gold to protect it from the Sun's heat. An overglove that escaped from White's open hatch decayed from orbit within a few months and burned up in the atmosphere. White accidentally smeared McDivitt's window before returning to his seat and recovering the camera. He intentionally discarded his thermal overgloves and helmet sun visor before returning to Gemini 4. White remained comfortable in his Gemini G4C suit—he stated later that he was more comfortable during the EVA than at any other time during the flight until the hatch refused to close. In the 5-min struggle to shut it he exceeded the cooling capacity of his chest-mounted Ventilation Control Module (about 1000 btu/hr), slightly fogging his visor. Sweat streamed into his eyes until the cabin was repressurized and he removed his helmet. Because the hatch proved difficult to close, it was not reopened as planned to discard EVA equipment. Joseph Shea, Director of the Apollo Project Office, National Aeronautics and Space Administration (NASA) Manned Spacecraft Center (MSC), stated later that White's EVA showed that Apollo Lunar Excursion Module crew members would be able to cross to the Apollo Command Module (CM) after ascent from the lunar surface if the two spacecraft could not dock. He also stated that engineers were considering wrapping the CM in cloth to protect it from particles deposited by the solid-fuel rockets which would jettison the Apollo launch escape tower. After reaching space, an astronaut would perform an EVA to peel off the cloth layer.
Gemini 4, 1965—Edward White II performs the first U.S. EVA. He wears a G4C space suit. Note the HHMU (top right) and White's VCM chestpack. (S65-30433)
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Summary of Gemini Extravehicular Activity, NASA SP 149, 1967; "Life Support Systems for Extravehicular Activity," Harold McMann, Elton Tucker, Marshall Horton, and Frederick Burns, in Gemini Summary Conference, NASA SP 136, February 1967, p. 73; On the Shoulders of Titans: A History of Project Gemini, Barton Hacker and James Grimwood, NASA SP 4203, 1977, pp. 246-250; Project Gemini: A Chronology, NASA SP 4002, 1969, pp. 200-202; "Gemini 4 Paves Way for Bolder Program," Aviation Week & Space Technology, June 7, 1965, p. 18; "Gemini 4 Success to Intensify Launch Pace," Aviation Week & Space Technology, June 14, 1965, p 83; "Gemini 4 Data to Aid Future Manned Flight," George Alexander, Aviation Week & Space Technology, June 21, 1965, p. 79; "Gemini 4 Medical Results Indicate Feasibility of 14-Day Spaceflights," Erwin Bulban, Aviation Week & Space Technology, June 21, 1965, p. 81; Personal Logs, Joseph McMann.
June 7
Gemini 4 splashdown
August 21-29
Gemini 5
December 4-18
Gemini 7
December 15-16
Gemini 6
1966
March 16
Gemini 8
June 3
Gemini 9 launch
June 5
1966 EVA 1
World EVA 3
U.S. EVA 2
Duration: 2:09 Spacecraft/mission: Gemini 9 Crew: Thomas Stafford, Eugene Cernan Spacewalker: Eugene Cernan Purpose: Conduct first complex EVA; test the AMU
The ease with which White adapted to EVA on Gemini 4 and the cancellation of David Scott's Gemini 8 EVA due to spacecraft problems encouraged EVA planners to schedule a full slate of activities for Eugene Cernan's Gemini 9 spacewalk. According to the mission plan, Gemini 9 would dock with the Augmented Target Docking Adapter (ATDA). Mission Pilot Cernan would emerge and retrieve an experiment package from the ATDA, then move to Gemini 9's aft adapter section, where the Astronaut Maneuvering Unit (AMU) was stowed. He would unfold its arms, attach himself to its integral life support system, unfasten his 7.5-m (25-ft) tether, and fly up to 45 m (150 ft) from Gemini 9. The crew reached the ATDA in orbit on June 3 to find that its launch shroud was still attached, preventing docking. Rendezvous efforts were tiring, so Command Pilot Thomas Stafford postponed the EVA for 24 hr. On this date Cernan emerged just before orbital dawn. He used an Environmental Life Support System (ELSS) chestpack similar to the one Scott would have used on Gemini 8, but lacked an HHMU. His G4C suit legs were modified with steel fabric and aluminized film layers to ward off heat from the AMU's hydrogen peroxide rockets. The thick, complex tether proved difficult to manage (Cernan called it "the snake"). Then Cernan moved to the AMU. Handrails, velcro pads, and loop foot restraints failed to help him control his movements. Cernan stated later that he "had to work continually against the pressure suit... I was devoting 50 percent of my workload just to maintain position." As he struggled, he broke off an experiment antenna mounted on Gemini 9 and tore the outer layers of his suit. His exertions exceeded the capacity of the ELSS to remove moisture, fogging his faceplate and blinding him. Cernan donned the AMU by touch, but Stafford called him back inside. Cernan also experienced "hot spots" on his back caused by sunlight striking torn places on his suit. After returning to Earth, Cernan conducted underwater neutral buoyancy simulations of his EVA in the Weightless Immersion Facility pool at NASA MSC. He reported that neutral buoyancy simulation nearly duplicated actual EVA conditions, helping to validate it as an EVA training tool.
Astronautics and Aeronautics, 1966, NASA SP 4007. pp. 202, 206-207, 218; Summary of Gemini Extravehicular Activity, NASA SP 149, 1967; "Life Support Systems for Extravehicular Activity," Harold McMann, et al, in Gemini Summary Conference, NASA SP 136, February 1967, p. 71-72; "Body Positioning and Restraints During Extravehicular Activity," David Schulz, et al, in Gemini Summary Conference, NASA SP 136, February 1967, pp. 79-90; Project Gemini: A Chronology, NASA SP 4002, 1969, pp. 245-246; On the Shoulders of Titans: A History of Project Gemini, NASA SP 4203, 1977, pp. 337-339.
June 6
Gemini 9 splashdown
July 18
Gemini 10 launch
July 19
1966 EVA 2
World EVA 4
U.S. EVA 3
Duration: 0:49 Spacecraft/mission: Gemini 10 Crew: John Young, Michael Collins Spacewalker: Michael Collins Purpose: SEVA to conduct photography
Gemini 10 docked with Agena 10 on July 18. Command Pilot John Young and Mission Pilot Michael Collins had to compensate for a trajectory error, leaving Gemini 10 with only half the fuel planned when the docking occurred. They then repeatedly fired Agena 10's engine to match orbits with Agena 8. Collins performed this Stand-up EVA (SEVA), the first of two EVAs planned for the mission, during the climb to Agena 8. He used a 70-mm camera to snap 22 images of the southern Milky Way in the ultraviolet part of the spectrum. As the docked Gemini 10 and Agena 10 spacecraft passed into daylight Collins took photos of a colored plate to determine if film accurately captured colors in space. Collins and Young then experienced eye irritation and smelled a strange odor in their suits. This was apparently caused by lithium hydroxide leaking into their helmets when both suit fans operated simultaneously. Lithium hydroxide in the Gemini life support system absorbed exhaled carbon dioxide.
Astronautics and Aeronautics, 1966, NASA SP 4007. pp. 243-244; Summary of Gemini Extravehicular Activity, NASA SP 149, 1967; On the Shoulders of Titans: A History of Project Gemini, NASA SP 4203, 1977, pp. 347-348.
As they matched orbits with Agena 8, Young and Collins separated Gemini 10 from Agena 10. Mindful of their scarce fuel, they rendezvoused with Agena 8 on this date about 90 min before the planned second EVA. They checked out their suits, prepared the cabin for depressurization, and wiped the inside of their helmet visors with an antifogging chemical. Collins then donned his ELSS chestpack and unstowed the umbilical which carried oxygen, communications, and nitrogen. The nitrogen, propellant for the HHMU, was stored under pressure in a tank in Gemini 10's adapter section. Freed from stowage, the umbilical filled the cockpit. Ground controllers told the astronauts to leave one of the two suit fans turned off to prevent lithium hydroxide from invading the suit loop again. Collins' second EVA was scheduled to last 90 min. He left the cabin, unfolded a handrail, and removed a micrometeoroid package attached to Gemini 10. He had to avoid the 16 thrusters Young used to keep the spacecraft close to Agena 8. The Gemini 10 hand controllers were modified to make piloting the spacecraft easier during EVA proximity operations while in a pressurized suit with restricted wrist mobility. This modification was later applied to the Apollo lunar rover. Collins then prepared to move to Agena 8 to retrieve a micrometeoroid package. He plugged a line hanging loose from his umbilical into the nitrogen connector on Gemini 10's adapter section. Collins described this task in his autobiographical book Carrying the Fire:
my legs are flailing back and forth in response to the slightest torque that my arms put on the rail or the connector... I have missed on my first attempt to stab the connector with the fitting on the end of my umbilical. The sleeve on the fitting has sprung forward and must be recocked, but that is a two-handed operation. I let go of the rail for an instant, recock the sleeve and grab the rail again. In the process I swing wildly and bang up against the side of the spacecraft. John feels the commotion, and so does the Gemini's attitude control system, which reacts to this unwanted motion by firing thrusters.
Collins guided Young as he maneuvered Gemini 10 to within 3 ft of the Agena, then Collins jumped to it. He gripped the Agena docking cone, dislodging a sharp-edged electric discharge ring which he feared might tear his suit or cut his umbilical. Young meanwhile kept track of a "3-body problem" involving Gemini 10, Collins, and Agena 8, all the while trying to keep sunlight from falling on Collins' ejection seat. The seat might have fired—taking Gemini 10's hatches with it—if it had been heated by the Sun for too long. Reaching the micrometeoroid package, Collins attempted to stop his forward motion, but his lower body momentum left him "turning lazy cartwheels somewhere above and to the left of everything that matters." He used the HHMU to stop his rotation, landed among the thrusters behind the Gemini 10 cockpit, and caught himself on his open hatch door. He then used the HHMU to move to the Agena. He retrieved the micrometeoroid package, but set the Agena gyrating, making it more difficult for Young to keep Gemini 10 close. He elected not to install a replacement package as planned. Gemini 10's fuel supply dropped dangerously low, forcing Young to call Collins back inside and cut short the EVA. Collins discovered that he had lost his camera, then the long umbilical caused problems again, preventing Young from seeing the control panel so he could report fuel usage to Houston and causing Collins to accidentally shut off the radio. They herded the umbilical into a bag with empty food containers and disused equipment and opened the hatch just long enough to toss it out. Collins' EVA was more successful than Cernan's, though he reported later that the "basic problem" of EVA remained that "without some sort of handholds or restraining devices, a large percentage of the astronaut's time is... devoted to torquing his body around until it is in the proper position to do some useful work." Gemini 10 was the first U.S. space mission preceded by underwater EVA training. Speaking in 1996, Young stated that he was under orders from Donald Slayton, Chief of the Astronaut Office, to get Collins back into the spacecraft if he became incapacitated. However, according to Young, "there was no way if anything happened to somebody going outside a Gemini that you could get them back in." The seat was too narrow and the pressure suit too stiff to put an EVA astronaut into the cockpit without his cooperation.