January 17
Soyuz 4 landing
January 18
Soyuz 5 landing
March 3
Apollo 9 launch
March 6
1969 EVA 2
World EVA 12
U.S. EVA 10
Duration: 0:46 Spacecraft/mission: Apollo 9 Crew: James McDivitt, Russell Schweickart, David Scott Spacewalkers: Russell Schweickart, David Scott Purpose: Demonstrate contingency EVA transfer between Apollo LM and CM; test A7L suit and PLSS; test LM and CM ability to support EVA
Lunar Module Pilot (LMP) Russell Schweickart suffered two bouts of vomiting one day after launch and Command Module Pilot (CMP) David Scott reported feeling ill. These symptoms of space motion sickness caused Commander (CDR) James McDivitt and Mission Control to limit Schweickart's scheduled 2-hr EVA to a test of the Apollo A7L Extravehicular Mobility Unit (EMU) and Portable Life Support System (PLSS) inside the Lunar Module (LM) Spider's cabin. For the revised EVA, which would occur in daylight and last less than 1 hr, Spider and CM Gumdrop would be depressurized and their external hatches opened. The EMU tested on Apollo 9 and used on Apollo lunar missions 11 through 14 weighed about 85 kg (185 lb) fully charged and included three main parts:
- A7L Pressure Garment Assembly (PGA), the "man-shaped" part of the EMU
- Portable Life Support System (PLSS) backpack connected to the PGA by hoses and harnesses
- Oxygen Purge System contingency oxygen supply
The A7L EVA PGA weighed 19.69 kg (43.42 lb). For lunar landing missions the CDR and LMP wore the EVA version both on the lunar surface and during operations requiring them to suit up inside the CM spacecraft. The CMP wore the lighter, stiffer IV version with a thinner integrated thermal meteoroid garment outer layer than the EVA version. On the Apollo 9 through 14 suits, the astronaut entered through a zippered opening running from the front of the crotch up the back. The PGA also included a custom-sized integral boot with a heel clip for securing the legs to the CM couch during launch and reentry. Moonwalkers wore sturdy lunar boots over the integral boots on the lunar surface. During EVA the PGA was worn over the Liquid Cooling Garment (LCG), a nylon-spandex coverall worn next to the astronaut's skin. Cooling water flowed through tiny plastic tubes in the LCG, carrying away excess heat to the sublimator in the PLSS. The PGA pressure bladder was designed to operate at an internal pressure of 25.88 kilopascal (3.75 psi). The neoprene-coated nylon bladder had dipped rubber convolute ("accordion") joints at shoulders, elbows, wrists, hips, knees, and ankles. Cables with reinforced attachment points prevented the convolute joints from ballooning, so they maintained "near-constant volume," and an upper arm bearing with restraining cables improved arm mobility. The chest area of the PGA included inlet and outlet gas connectors and a water connector with inlet and outlet manifolds. The A7L was topped by a locking neck ring to which attached the clear polycarbonate plastic pressure helmet assembly. The Lunar Extravehicular Visor Assembly (LEVA), an assortment of adjustable shades and filters, was worn over the polycarbonate helmet during EVA. The astronaut wore communications carrier assembly "snoopy hats" with redundant microphones and headphones. A drink bag was secured near the astronaut's neck. Custom-sized gloves were attached to wrist rings by rotating quick-disconnect couplings and equipped with a wrist convolute. The EVA gloves included additional outer layers to shield against abrasion from tools and lunar materials. These included high-strength silicone rubber-coated nylon tricot thumb and fingertip shells. The PLSS backpack provided air to the PGA and cooling water to the LCG. The backpack contained the oxygen ventilating circuit, the feedwater and liquid transport loops, the primary oxygen and electrical power subsystems, the EVA communications system, and the remote control unit. A heat exchanger (sublimator) provided cooling; the PLSS vented water vapor as part of the cooling process. Water recharge required less than 10 min. The PLSS provided oxygen and cooling water for about 5 hr of EVA. A hard cover and a thermal blanket covered the assembled unit. A single 16.8V DC battery provided PLSS electricity. The Oxygen Purge System was originally designed in 1967 to provide 30 min of emergency oxygen for breathing and suit cooling. The device could also supplement the main PLSS oxygen supply. A monopole radio communications antenna was considered part of the PLSS, but was mounted on top of the purge system. On mission day 4 Schweickart and McDivitt entered the LM. The astronauts depressurized the two spacecraft and McDivitt opened Spider's hatch. Schweickart was feeling better than expected, so McDivitt allowed him to egress and place his feet in the "golden slipper" foot restraint on Spider's porch. This was the only time the PLSS was tested in space prior to the Apollo 11 Moon landing. Schweickart took photographs while Scott opened the CM hatch, emerged partially, and retrieved thermal exposure samples from Gumdrop's exterior. Scott's SEVA was designed to demonstrate the CMP's ability to prepare the CM for contingency EVA transfer by the LMP and CDR from the LM in the event of docking or IV transfer problems. Scott, who remained connected to Gumdrop's life support system through an umbilical, wore one EVA glove and one IV glove; he found that the IV hand grew slightly warm. Schweickart performed well in the foot restraint, so McDivitt permitted him to test handrails and retrieve thermal samples on Spider's exterior. Movement using the handrails was easier in space than during training, Schweickart reported. He returned to Spider, and the astronauts closed the hatches and repressurized the two spacecraft. McDivitt and Schweickart practiced recharging the PLSS before returning to Gumdrop.
Chariots for Apollo, NASA SP 4205, Courtney Brooks, et al, 1979, pp. 294-298; Manned Spacecraft Log, Tim Furniss, 1983, p. 59; "Getting It All Together," George Mueller, in Apollo Expeditions to the Moon, NASA SP 350, Edgar Cortwright, editor, 1975, pp. 190, 192; Andrew Chaikin, May 3, 1996; John Charles, May 3, 1996; Joel Powell, May 2, 1996; Apollo Operations Handbook: Extravehicular Mobility Unit, Vol. 1, System Description, Rev. IV, MSC- 01372-1, June 1968; Apollo Experience Report—Development of the Extravehicular Mobility Unit, NASA TN D-8093, Charles Lutz, Harley Stutesman, Maurice Carson, and James McBarron, NASA, November 1975; Apollo 11 Press Kit, pp. 117-122; Apollo 14 Press Kit, pp. 64-67; interview, David S. F. Portree with James McBarron, July 16, 1996.
March 13
Apollo 9 splashdown
May 18-26
Apollo 10
July 16
Apollo 11 launch
July 20
1969 EVA 3
World EVA 13
U.S. EVA 11
Lunar Surface EVA 1
Duration: 2:32 Spacecraft/mission: Apollo 11 Crew: Neil Armstrong, Edwin Aldrin, Michael Collins Moonwalkers: Neil Armstrong, Edwin Aldrin Purpose: Fulfill political requirement of placing a man on the lunar surface; demonstrate ability to perform lunar surface EVA; collect surface samples; deploy EASEP
The first Apollo landing site, in the southern Sea of Tranquility about 20 km (12 mi) southwest of the crater Sabine D, was selected in part because it had been characterized as relatively flat and smooth by the automated Ranger 8 and Surveyor 5 landers, as well as by Lunar Orbiter mapping spacecraft, and therefore unlikely to present major landing or EVA challenges. Two hr after avoiding touchdown in a crater full of 3-m (10-ft) boulders, Armstrong and Aldrin received permission to go outside the LM Eagle four and a half hr early. They planned placement of the Early Apollo Scientific Experiment Package (EASEP) and the U.S. flag by studying their landing site through Eagle's twin triangular windows, which gave them a 60-deg field of view. Preparation required longer than the 2 hr scheduled. Armstrong had some initial difficulties squeezing through the hatch with his PLSS. According to veteran moonwalker John Young, a redesign of the LM to incorporate a smaller hatch was not followed by a redesign of the PLSS backpack, so some of the highest heart rates recorded from Apollo astronauts occurred during LM egress and ingress. The Remote Control Unit controls on Armstrong's chest prevented him from seeing his feet. While climbing down the nine-rung ladder, Armstrong pulled the D-ring which deploys the Modular Equipment Stowage Assembly (MESA) folded against Eagle's side and activated the TV camera. Ghostly black and white images of the first lunar EVA were immediately broadcast to at least 600 million people on Earth. After describing the surface ("very fine grained... almost like a powder"), Armstrong stepped off Eagle's footpad and into history as the first human to set foot on another world. He reported that moving in the Moon's gravity, one-sixth of Earth's, was "perhaps even easier than the simulations." In addition to fulfilling President John F. Kennedy's mandate to land a man on the Moon before the end of the 1960s, Apollo 11 was an engineering test of the Apollo system; therefore, Armstrong snapped photos of the LM so engineers would be able to judge its post-landing condition. He then collected a contingency soil sample using a sample bag on a stick. He folded the bag and tucked it into a pocket on his right thigh. He removed the TV camera from the MESA, made a panoramic sweep, and mounted it on a tripod 12 m (40 ft) from the LM. The TV camera cable remained partly coiled and presented a tripping hazard throughout the EVA. Aldrin joined him on the surface and tested methods for moving around, including two-footed kangaroo hops. The PLSS backpack created a tendency to tip backwards, but neither astronaut had serious problems maintaining balance. Loping became the preferred method of movement. The astronauts reported that they needed to plan their movements six or seven steps ahead. The fine soil was quite slippery. Aldrin remarked that moving from sunlight into Eagle's shadow produced no temperature change inside the suit, though the helmet was warmer in sunlight, so he felt cooler in shadow. Together the astronauts planted the U.S. flag—the ground was too hard to permit them to insert the pole more than about 20 cm (8 in)—then took a phone call from President Richard Nixon. The MESA failed to provide a stable work platform and was in shadow, slowing work somewhat. As they worked, the moonwalkers kicked up gray dust which soiled the outer part of their suits, the integrated thermal meteoroid garment. They deployed the EASEP, which included a passive seismograph and a laser ranging retroreflector. Then Armstrong loped about 120 m (400 ft) from the LM to snap photos at the rim of East Crater while Aldrin collected two core tubes. He used the geological hammer to pound in the tubes—the only time the hammer was used on Apollo 11. The astronauts then collected rock samples using scoops and tongs on extension handles. Many of the surface activities took longer than expected, so they had to stop documented sample collection halfway through the allotted 34 min. During this period Mission Control used a coded phrase to warn Armstrong that his metabolic rates were high and that he should slow down. He was moving rapidly from task to task as time ran out. Rates remained generally lower than expected for both astronauts throughout the walk, however, so Mission Control granted the astronauts a 15-min extension. Aldrin entered Eagle first. With some difficulty the astronauts lifted film and two sample boxes containing more than 22 kg (48 lb) of lunar surface material to the LM hatch using a flat cable pulley device called the Lunar Equipment Conveyor. Armstrong then jumped to the ladder's third rung and climbed into the LM. After transferring to LM life support, the explorers lightened the ascent stage for return to lunar orbit by tossing out their PLSS backpacks, lunar overshoes, one Hasselblad camera, and other equipment. Then they lifted off in Eagle's ascent stage to rejoin CMP Michael Collins aboard the CM Columbia in lunar orbit.