Man Lands on the Moon – July 20th 1969

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Historical clothing design of the day is to commemorate Man Walking on the Moon – July 20th 1969. Each day a new design is chosen and an article is posted to highlight the historical significance of the design.

Lunar descent

Man Lands on the Moon - July 20th 1969 History Clothing & Gifts - Long Sleeve Men's ShirtOn July 20, 1969 the lunar module (LM) Eagle separated from the command module Columbia. Collins, alone aboard Columbia, inspected Eagle as it pirouetted before him to ensure the craft was not damaged.

As the descent began, Armstrong and Aldrin found that they were passing landmarks on the surface 4 seconds early and reported that they were “long”: they would land miles west of their target point.

Five minutes into the descent burn, and 6,000 feet above the surface of the Moon, the LM navigation and guidance computer distracted the crew with the first of several unexpected “1202″ and “1201″ program alarms. Inside Mission Control Center in Houston, Texas, computer engineer Jack Garman told guidance officer Steve Bales it was safe to continue the descent and this was relayed to the crew. The program alarms indicated “executive overflows”, where the guidance computer could not complete all of its tasks in real time and had to postpone some of them. During the mission the blame was placed on a switch being in the wrong position which meant that the computer was processing data from two radars instead of one. However an internal NASA report two years later concluded that the problem was the same peripheral hardware design bug that had been seen previously during Apollo 5 testing.  A design flaw with the rendezvous radar meant that depending upon how the hardware randomly powered up a stationary antennae could appear to the computer to be dithering backwards and forwards between two adjacent positions. The extra spurious cycle stealing as the rendezvous radar updated an involuntary counter caused the computer to run slowly enough to cause the alarms.

When Armstrong again looked outside, he saw that the computer’s landing target was in a boulder-strewn area just north and east of a 300 metres (980 ft) diameter crater (later determined to be “West crater”, named for its location in the western part of the originally planned landing ellipse). Armstrong took semi-automatic control and, with Aldrin calling out altitude and velocity data, landed at 20:17 UTC on July 20 with about 25 seconds of fuel left.Man Lands on the Moon - July 20th 1969 History Clothing & Gifts - Women's Pajamas

Armstrong continued with the remainder of the post landing checklist, “Engine arm is off.” before responding to Duke with the words, “Houston, Tranquillity Base here. The Eagle has landed.” Armstrong’s abrupt change of call sign from “Eagle” to “Tranquillity Base” caused momentary confusion at Mission Control and Duke remained silent for a couple of seconds before expressing the relief of Mission Control: “Roger, Twan– Tranquillity, we copy you on the ground. You got a bunch of guys about to turn blue. We’re breathing again. Thanks a lo

Two and a half hours after landing, before preparations began for the EVA, Aldrin broadcast that:

“This is the LM pilot. I’d like to take this opportunity to ask every person listening in, whoever and wherever they may be, to pause for a moment and contemplate the events of the past few hours and to give thanks in his or her own way.”

The schedule for the mission called for the astronauts to follow the landing with a five-hour sleep period, since they had been awake since early morning. However, they elected to forgo the sleep period and begin the preparations for the EVA early, thinking that they would be unable to sleep.

Lunar surface operations

The astronauts 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° field of view. Preparation required longer than the two hours scheduled. Armstrong initially had some difficulties squeezing through the hatch with his Portable Life Support System (PLSS). According to veteran moon-walker John Young, a redesign of the LM to incorporate a smaller hatch had not been 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.

At 02:39 UTC on Monday July 21 (10:39pm EDT, Sunday July 20), 1969, Armstrong opened the hatch, and at 02:51 UTC began his descent to the lunar surface. The Remote Control Unit controls on his chest kept him from seeing his feet. Climbing down the nine-rung ladder, Armstrong pulled a D-ring to deploy the Modular Equipment Stowage Assembly Man Lands on the Moon - July 20th 1969 History Clothing & Gifts - Messenger Bag(MESA) folded against Eagle’s side and activate the TV camera, and at 02:56 UTC (10:56pm EDT) he set his left foot on the surface. The first landing used slow-scan television incompatible with commercial TV, so it was displayed on a special monitor and a conventional TV camera viewed this monitor, significantly reducing the quality of the picture. The signal was received at Goldstone in the USA but with better fidelity by Honeysuckle Creek Tracking Station in Australia. Minutes later the feed was switched to the more sensitive Parkes radio telescope in Australia. Despite some technical and weather difficulties, ghostly black and white images of the first lunar EVA were received and broadcast to at least 600 million people on Earth. Although copies of this video in broadcast format were saved and are widely available, recordings of the original slow scan source transmission from the lunar surface were accidentally destroyed during routine magnetic tape re-use at NASA. Archived copies of the footage were eventually located in Perth, Australia, which was one of the sites that originally received the Moon broadcast.

After describing the surface dust as “fine and almost like a powder”, Armstrong stepped off Eagle’s footpad and into history as the first human to set foot on another astronomical body. It was then that he uttered his famous line “That’s one small step for [a] man, one giant leap for mankind” six and a half hours after landing. Aldrin joined him, describing the view as “Magnificent desolation.”

Armstrong said that moving in the lunar gravity, one-sixth of Earth’s, was “even perhaps easier than the simulations… It’s absolutely no trouble to walk around”.

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.

After the astronauts planted a U.S. flag on the lunar surface, they spoke with President Richard Nixon through a telephone-radio transmission which Nixon called “the most historic phone call ever made from the White House.” Nixon originally had a long speech prepared to read during the phone call, but Frank Borman, who was at the White House as a NASA liaison during Apollo 11, convinced Nixon to keep his words brief, out of respect of the lunar landing being Kennedy’s legacy.Man Lands on the Moon - July 20th 1969 History Clothing & Gifts - Hoodie

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 metres (390 ft) from the LM to snap photos at the rim of Little West 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 documenting sample collection halfway through the allotted 34 min.

Lunar ascent and return

Aldrin entered Eagle first. With some difficulty the astronauts lifted film and two sample boxes containing more than 22 kilograms (49 lb) of lunar surface material to the LM hatch using a flat cable pulley device called the Lunar Equipment Conveyor. Armstrong reminded Aldrin of a bag of memorial items in his suit pocket sleeve, and Aldrin tossed the bag down; 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. They then pressurized the LM, and settled down to sleep.

While moving within the cabin, Aldrin accidentally broke the circuit breaker that would arm the main engine for lift off from the Moon. There was concern this would prevent firing the engine, stranding them on the Moon. Fortunately a felt-tip pen was sufficient to activate the switch. Had this not worked, the Lunar Module circuitry could have been reconfigured to allow firing the ascent engine

After about seven hours of rest, the crew was awakened by Houston to prepare for the return flight. Two and a half hours later, at 17:54 UTC, they lifted off in Eagle’s ascent stage, carrying 21.5 kilograms of lunar samples with them, to rejoin CMP Michael Collins aboard Columbia in lunar orbit. During the launch Aldrin looked up in time to see the exhaust from the ascent module’s engine knock over the American flag they had planted.[ After more than 2½ hours on the lunar surface, they had left behind scientific instruments which included a retroreflector array used for the Lunar Laser Ranging Experiment and a Passive Seismic Experiment used to measure Moon quakes. They also left an American flag, an Apollo 1 mission patch, and a plaque (mounted on the LM Descent Stage ladder) bearing two drawings of Earth (of the Western and Eastern Hemispheres), an inscription, and signatures of the astronauts and President Richard M. Nixon. The inscription read:

 Here Men From The Planet Earth First Set Foot Upon the Moon, July 1969 A.D. We Came in Peace For All Mankind.

Read More about the Apollo 11 Mission on Wikipedia.

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