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22 July 1969: Coast back to Earth
Today Apollo 11 is coasting back to Earth. The astronauts are tired, and spend a lot of very well deserved time sleeping.
Today they do make just one mid-course correction, which is all they need for a perfect coast home.
For those of you in the San Francisco Bay area, the USS Hornet museum, which houses the ship that will pick up our astronauts from the middle of the Pacific ocean on Friday, is hosting a splashdown party where Buzz Aldrin himself will be there to officiate on Saturday, July 25th, 2009.
What are those crosses all over the Moon photos? As I knew since I was a kid (my dad was an engineer), those are marks from the Reseau plate.
A Reseau plate is a sheet of glass right in front of the film that is engraves with small markings. In the case of the Apollo flights, these marks were exactly 1cm apart.
The purpose of the Reseau plate is that it forever marks the images with exact distances so that measurements can be made from them later, regardless of localizes or general film shrinkage or expansion, and today, regardless of how I fold, spindle or mutilate the sizes for Internet display.
Since most of the shots were made with Zeiss' special no-distortion 60mm f/5.6 Biogon lens, one can calculate exactly the angles between points on the image.
21 July 2009
21 July 1969: Ascent from the lunar surface
See the front-page news of yesterday's moon walk, as published around the world. Sorry if some of you don't remember how excited we all were back in 1969; this was the matter-of-fact language used in those days. This event was that incredible.
For the past week I've been watching this unfold live at WeChooseTheMoon.org , which had the best live coverage from the 6:32 AM PDT 16 July launch of Apollo XI through the 7:56:15 PM PDT first steps of Man on the Moon last night.
WeChooseTheMoon.org, a product of the Kennedy Presidential Library, must be lauded for putting as much money as they did into assembling the live coverage, but sadly their budget ran out right as the men got out of the LEM.
WeChooseTheMoon.org has no coverage of the 2-1/4 hour moon walk itself, which was the whole point of the trip, and instead of live coverage of the rest of this week's return to Earth, which is at least as difficult as getting to the Moon in the first place, WeChooseTheMoon.org summarizes the return as nothing more than a 30-second slide show. Oh well; I got to bed early last night.
Drats, I was planning to watch the whole moon walk last night live again, as I did back in 1969.
All of us kids and our friends were extremely stoked by the whole thing. The LEM was built by Grumman in Bethpage, Long Island, NY, about 4 miles from my house. My dad worked at Sperry across the street from Canon USA's headquarters in Lake Success, and our house was only a few miles from Nikon USA's HQ in Melville, but half my friend's dads' worked at Grumman and helped build this thing. Kids at my Old Bethpage Grade School would brag about who's dad was building what.
A reader who lived even closer pointed out that all his neighbors in Bethpage were LEM engineers. One day the engine head of his lawnmower cracked. A neighbor offered to fix it. The engineer ran into his garage and brought over a tube of epoxy. He explained that the same epoxy was used on the LEM, and that once a tube was opened and not used up the same day, that it could not be used later. Thus the engineers took home all the half-used epoxies, and many homes in and around Bethpage have things held together with genuine LEM epoxy! Talk about trickle-down benefits of the Apollo mission!
Just like most aircraft, most of the critical systems had backups, and backups on those backups. The biggest thing that had no backup was the ascent stage rocket. There was only one motor. If it failed to fire, the guys were stranded on the moon to die a slow, painful death as the world watched.
I had never realized this, but the designer of the LEM, Grumman's Thomas J. Kelly, was also a winner of the Grumman Scholarship coming out of high school decades before. He was already 50 in 1969, and in 1980 I became a runner-up for the same engineering scholarship. Thankfully I didn't completely win, because instead of attending the all-boys' engineering college my dad did, I attended SUNY Stony Brook instead. If you think I'm a nerd today, Heaven only knows how nerdly I'd be if I attended an engineering-only school instead of a real university where I also got to study everything else.
Here's what's happening today. Our guys slept most of the night, and are still in the LEM on the surface of the Moon about to blast off and begin their ascent on the first leg of their trip back to Earth.
9:54:01 AM PDT (12:54 PM EDT, 17:54UT, MET 124:22:01): Lunar Ascent
Aldrin and Armstrong were sure hoping the 172-pound ascent engine fired. If it didn't, they would be stuck on the moon for the rest of their lives, which probably wouldn't be more than a week before they succumbed to the elements.
Since there was only one motor, Grumman kept it simple. It has no pumps like the F-1 motors of the Saturn V; the LEM's made-on-Long Island ascent engine needed no ignition system as well as no pumps: it ignited as soon as the propellants touched (hypergolic) after feeding into the engine via gravity. Thank God Grumman used the correct gravity value — for the Moon! (other sources point to a pressurised helium system held in two 2.9 kg tanks at 21 MPa.)
The engine underwent 3,000 test firings — but all that mattered was right now.
The top half of the Lunar Module, the Ascent Stage, sucessfully fired off from bottom half of the LEM (the Descent Stage, which was left on the Moon) after 21 hours, 36 minutes on the lunar surface. Astronauts Neil A. Armstrong, commander, and Edwin E. Aldrin Jr., lunar module pilot, in the LM, were now returning from the lunar surface.
Neil Armstrong in the LEM as they are ascending back to the CSM.
The Ascent Module of the LEM approaches the CSM. enlarge.
2:34PM PDT (5:34PM EDT, 21:34:00 UT): Docking
The LEM docked with the Command Module, and Aldrin and Armstrong, coming up from the Moon, climbed back into the Command Module.
Close-up of the LEM's docking target as seen from the Command Module as it docked. bigger.
5:01:01 PM PDT (8:01PM EDT, 00:01:01 UT): LEM Jettisoned
After docking with the CSM, the Eagle (the ascent stage of the LEM) was jettisoned into lunar orbit.
NASA says it should have crashed back into the moon a few months later, and since it wasn't tracked, no one knows where it landed.
9:54:42 PM PDT (12:54 AM EDT, 04:54 UT): TEI: Return to Earth
Transearth injection began with a 2 1/2 minute firing of the CSM main engine.
As we learned during the TLI, translunar injection, on 16 July 1969, the TEI pushes the Command and Service Modules out of Lunar orbit on their way back to Earth.
Once the TEI is complete and the CSM is on a transearth path, all it does is cost for the next three days until they arrive back at Earth for reentry.
For as long as Man has existed, Man's curiosity has led him to wonder about things that he could see, but that he could not touch.
For over 400,000 years, men have dreamt about traveling to the moon.
Man's imagination grew large enough that he was able to conceive, design and build a ship in which he could complete that journey.
Forty years ago today, men flew a ship that they had built, which had left the planet Earth four days earlier, and landed it on the surface of the Moon.
And then they got out.
Today we commemorate the power of over 400,000 years of Man's imagination.
Today we remember the day that Man learned that absolutely nothing is impossible.
As a child eventually learns how to pull a chair over to climb up to a countertop, for the first time in all of Man's history, Man had learned how to climb up to another celestial body.
Man had reached a new chapter in his development.
It is forty years ago today that we learned that the only limitation to how high we can climb is the depth of our imaginations.
We learned that the most powerful thing Man has ever created is not the Saturn V rocket, but the unbounded power of our imaginations.
This is why we take today as a new holiday, Imagination Day. On July 20th each year we pause to imagine where we would like to go next and what we would like to accomplish. We pause to remember that we have no limitations except for those which we impose on ourselves.
We take this day to remember that everything we have ever created or accomplished is because that thing was first envisioned in someone's imagination, without which it would never have happened.
This event has even earned these men another visit to the white house today in 2009.
20 July 1969:
Apollo XI entered Lunar orbit yesterday, 19 July. With each orbit, they saw the Earth rise over the lunar surface.
They had so much to do that it took them a while to find a clean window and have a free hand to make some snaps, and here is one shot at f/5.6 and 1/250 with the 250mm on the Hasselblad:
Earthrise from Apollo. bigger.
While orbiting the Moon today, 20 July, Commander Neil Armstrong and Lunar Module Pilot Buzz Aldrin climbed into the Lunar Module for a final checkout all LEM and space suit functions. Command Module Pilot Michael Collins remained in the Command Module.
The approach to Landing Site 2 on the Moon, as seen from the Lunar Module as they orbited. (The Command Module is in the foreground.) bigger.
Landing Site 2 is in the southwestern Sea of Tranquility. When this picture was made, the LEM was still docked to the Command and Service Modules (CSM). Site 2 is located just right of center at the edge of the darkness. The crater Maskelyne is the large one at the lower right. Hypatia Rille (U.S. 1) is at upper left, with the crater Moltke just to the right (north) of it. Sidewinder Rille and Diamondback Rille extend from left to right across the center of the picture. This view looks generally west.
11:11:53 PDT (2:11PM EDT or 18:11UT): LEM Undocking
The Lunar Module erected its landing gear and separated from the Command and Service Module.
Michael Collins gave the Lunar Module a visual inspection from the Command Module to be sure that it hadn't been damaged during the flight.
The Eagle has wings. bigger.
The Eagle, nickname for the LEM, is undocked and free from the Command and Service Modules. It is flying on its own.
Inside the LEM are astronauts Neil A. Armstrong, commander, and Edwin E. Aldrin Jr., lunar module pilot. Michael Collins, command module pilot, remained with the CSM in lunar orbit and snapped this photo.
The Apollo 11 Lunar Excursion Module (LEM) is in its lunar landing configuration, which has both the bottom half (descent stage) and top half (ascent stage) connected.
The protrusions connected to the landing pods are five-foot long (1.5m) sensors to aid in the touchdown (landing) process.
The CSM as seen from the LEM just before it starts to descend. bigger.
12:08 PM PDT (3:08PM EDT or 19:08UT): Descent Orbit Injection
At MET (Mission Elapsed Time) of 100:33:07, the Lunar Module descent engine fired for 29.8 seconds with 9,800 pounds of thrust, putting the Lunar Module into a descent orbit of 57.2 x 8.5 Nautical Miles. This means the closest approach of this orbit is 9 miles (14.5 km) above the Moon's surface.
This is called DOI, Descent Orbit Injection. Descent Orbit means they free-fall out of space from 9 miles to just 50,000 feet above the surface of the Moon.
Buzz Aldrin inside the LEM during the lunar descent. bigger. (photo: Neil Armstrong, commander, NASA)
Now is not the time to discuss this, but if you look at the left side of the image, you can see a perfect example of awful bokeh. The glint of light on each switch has turned into a donut instead of a nice, soft circle.
1:05 PM PDT (4:05 PM EDT or 20:05 UT): Final Approach
The Lunar Module descent engine fired for 12-1/2 minutes (756.3 seconds) to slow the craft as it fell out of space from 50,000 feet and down to the surface of the moon.
No one had ever landed here before. All we knew was what we had learned from various unmanned landing probes and and flyover mapping missions. We had what we thought was a good spot picked out, but we wouldn't know if Armstrong, Aldrin and the LEM were going to bounce off solid rock below the surface, or get sucked into a giant sinkhole. We went anyway.
As they were descending, Armstrong noted that they were passing marks ahead of plan, meaning that they would land long of the numbers and be miles away from where they had planned to land.
About 8 minutes before landing, the computer started throwing out error messages which had never been seen before. The astronauts had trained to cover every possibly conceivable error, and this is one that was considered so remote by the program that it was never covered in training.
In spite of these errors (program alarm 1202 and 1201 starting at MET 100:38:22), Armstrong continued his descent into relatively uncharted landing areas.
Since the LEM had to land a little further away than anticipated, it was running low on fuel. As the LEM descended under Armstrong's control, he was having to deal with these program alarms which were caused for unknown reasons, and a rapidly dwindling fuel supply.
Apollo control let him know that the computer guys said the computer was OK so long as these errors, caused for unknown reasons, didn't stay up constantly. Armstrong is still GO.
The computer guys knew the computer was overloading for some reason, and that reason won't become apparent until later.
With all these errors popping up, and the computer apparently sending him to land in a sea of boulders, Armstrong turned off the computer that was supposed to help him fly this thing.
Armstrong was now flying VFR by the seat of his pants, trying to find a place to land without landing on a big rock, and having only seconds of fuel left.
"Seconds of fuel left" means that if he didn't put it down within these last seconds, he would either have to abort the entire mission and return to the Command and Service Module, or that if he kept on, he could run out of the fuel needed to land safely (in other words, crash into the Moon), or try to land on whatever he could find now and pray that he didn't hit a rock.
Hitting a rock would be bad. If the LEM didn't land upright, they would not be able to launch back up to the Command and Service Module, and they would not likely be able to get out of the LEM and onto the moon. Even if they got out unhurt from a capsized LEM onto the Moon, they would not be able to return to the Command Module and would be left to die in space as the world watched helplessly. The LEM weighs tens of thousands of pounds; they couldn't hope to right it if it landed sideways.
The Hell with that. Armstrong kept going down.
Armstrong lands the LEM. bigger.
1:17:40 PM PDT (4:17 PM EDT or 20:17 UT): Landed
Armstrong landed the LEM at Mare Tranquilitatis, the Sea of Tranquility at MET 102:45:58, or after 12 minutes and 36 seconds of powered descent.
Armstrong reports "Houston, Tranquility Base here. The Eagle has landed."
Armstrong landed with only 25 seconds of fuel left. As I heard later in his verbal description of what went through his mind after all this, he said that after all this and landing on the moon, never again will he let anyone tell him anything is impossible. This showed him that no such thing as "impossible."
As Armstrong described it just after he set down, the computer was sending him to land in the middle of a "football-field sized crater with big boulders and rocks in and surrounding it to a diameter of 1.5 crater diameters," which led him to flying manually over the rock field to his landing point. The boulders were 5 to 10 feet across.
After landing, they checked everything to be sure it was safe to remain on the surface. If it wasn't, they would have blasted off and flew to the orbiting Command Module as soon as it was in the correct orbital position. They report adapting to 1/6 G is surprisingly easy.
Armstrong didn't know exactly where he had landed, since having to go to manual and work over the 1202 and 1201 alarms had taken precedence over taking fixes as he descended. He reports to Houston that he hasn't been able to pick out the things on the horizon just yet. Houston says don't worry; they'll figure it out. Houston did: they landed at 0.799º N 23.46º E, or 25 miles downrange of where they had intended.
NASA's plans called for the astronauts to take a nap for several hours once safely on the surface, since they had been awake for a long time today. Armstrong nixed that, raring to go get out there early.
Let's face it: after waiting only four weeks, there's no way I can sleep Christmas eve waiting to see what Santa brought me the next morning. Do you think anyone could sleep knowing they just got to the moon for the first time in 400,000 years of curiosity, with it all just outside their door? NASA should have thought of that.
They completed all their logging and checks, and began their EVA (Extra-Vehicular Activity or Moonwalk) preparations at 4:43PM PDT (7:43 PM EDT or 23:43 UT).
At MET 109:19:46, Armstrong was on the porch, ready to come out.
7:56:15 PM PDT (10:56PM EDT or 02:56 UT): They got out.
Neil Armstrong's First Step on the Moon. (as seen on on TV.)
Armstrong stepped onto the lunar surface, saying: "That's one small step for [a] man, one giant leap for mankind."
Neil Armstrong had just become the first living thing in history to set foot on any other celestial body.
As the most important event in all human history, one-sixth of the Earth's population watched this live on TV. TV was still in its infancy. People lucky enough to have TVs usually only had B&W TVs.
Buzz Aldrin followed 19 minutes later. Neil Armstrong snapped this photo with the Hasselblad:
Buzz Aldrin steps out and descends to the surface of the Moon. bigger.
Armstrong was such an extraordinary pilot that he made things more difficult for himself. The legs of the LEM were articulated and full of crunched tinfoil so that the tinfoil would crush on touchdown, letting the legs compress and absorb any impact. They landed so perfectly that the landing gear didn't need to compress — it was a gentle, smooth landing.
This left the LEM higher than intended, so there was a big distance from the bottom rung of the ladder to the surface of the moon. John Devaney, a Grumman engineer on duty in Houston, was afraid that it might have been so high that they wouldn't be able to to climb back into the LEM!
Because there is no wind on the moon, this footprint remains today, and forever until hit by a meteor, or something else.
The astronauts deployed the Early Apollo Scientific Experiment Package (EASEP) which included a passive seismograph and a laser ranging retroreflector, and other instruments, took photographs, and collected 50 pounds (21.55 kg) of lunar rock and soil.
A laser ranging retroreflector is the same kind of reflector that's on your tail lights or street signs. Shoot a light at it, and it reflects it back to you. You can still hit this reflector on the moon today. It was put there so we can clock laser beams and measure our exact distance to the moon.
Aldrin during the lunar EVA. bigger.
An EVA is an extra-vehicular activity, or getting out and waking around. The astronauts walked around for a total distance of about 800 feet (250 meters).
On one leg of the LEM is a plaque intended for whoever discovers the landing site next. No one has ever been back to that site; future missions went to different places.
The plaque on one leg of the LEM. bigger.
And this is what it says:
In case you are wondering why it's not also en Español, we also sent a half-inch (1cm) silicon disc on which was photoengraved messages of goodwill from heads-of-state from 73 countries.
This disc was made the same way we make computer chips, which at the time, had only been invented in a laboratory about 10 years ago. Most of the world still ran on vacuum tubes. Transistors, much less chips like this, were still rarely seen.
Message from Earth.
Messages from Earth.
We brought these messages from every corner of the Earth in every language. As the plaque says, we came in peace for all Mankind.
The gold olive branch. bigger.
We also left a gold olive branch as a symbol of peace.
Buzz Aldrin at the LEM. bigger.
Buzz Aldrin is removing the Early Apollo Scientific Experiments Package (EASEP) from its stowed position in the Lunar Module's (LEM) scientific equipment bay at the left rear quadrant of the descent stage looking forward.
Buzz as he sets out the instruments. bigger.
Edwin E. "Buzz" Aldrin Jr. just after he deployed the Early Apollo Scientific Experiments Package (EASEP). In the foreground is the Passive Seismic Experiment Package (PSEP); beyond it is the Laser Ranging Retro-Reflector (LR-3); in the center background is the United States flag; in the left background is the black and white lunar surface television camera; in the far right background is the Lunar Excursion Module (LEM).
Aldrin by a leg of the LEM. bigger.
It's obvious who carried the Hasselblad. All the snaps are of Buzz Aldrin, as taken by Neil Armstrong.
Apollo Control watching the lunar EVA.
10:11:13 PM PDT (1:11AM EDT or 5:11 UT): They got back in.
The EVA (Moonwalk or Extra-Vehicular Activity) ended at when the astronauts returned to the LEM and hooked back up to the LEM's life support system.
This EVA was the culmination of 400,000 years of Man's curiosity. The EVA lasted only 2 hours and 15 minutes.
They then chucked their life-support backpacks and a Hasselblad out the door to keep the weight down for their flight back tomorrow to the orbiting Command Module.
They closed the hatch, and went to sleep.
See and hear Eric Brace's music video, which includes some classic NASA footage.
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