ON THE SURFACE

Because four of Eagle’s six batteries were in its descent stage, the ascent stage had power just for the several hours required to rendezvous. As this could begin only when Columbia was conveniently positioned, there was a brief window once per revolution. Although Columbia had just passed below the horizon, a rendezvous would be feasible if Eagle were to lift off within the next 12 minutes. Thus, even as those around them were celebrating the act of landing, the flight controllers on duty were studying their telemetry for any evidence of a problem that would oblige an immediate liftoff. In planning, it had been decided to provide two decision points, referred to as T1 and T2: the first, barely 2 minutes after landing, was to be made on the basis of ‘first impressions’; the second was to be made just before the window closed, after a more thorough study. During training, Bill Tindall had expressed concern. By tradition, decisions were expressed as Go/No-Go, but in this case he saw scope for confusion: ‘‘Once we get to the Moon, does ‘Go’ mean stay on the surface, and does ‘No-Go’ mean abort from the surface? f think the decision should be changed to ‘Stay/No-Stay’ or something like that.’’ His advice had been accepted.

‘‘Let’s go on,’’ Armstrong said to Aldrin after they had completed the post­shutdown checklist, meaning that they should prepare for an immediate liftoff. Then he called Houston, ‘‘Okay, we’re going to be busy for a minute.’’

‘‘All flight controllers, about 45 seconds to T1 Stay/No-Stay,’’ Kranz observed. Although the flight controllers had maintained discipline on their intercom loops, some of the others present were celebrating. ‘‘Keep the chatter down in this room,’’ he ordered. ‘‘Okay, T1 Stay/No-Stay? Retro?’’

‘‘Stay!’’ replied Deiterich.

‘‘FfDO?’’

‘‘Stay!’’ replied Greene.

‘‘Guidance?’’

‘‘Stay!’’ replied Bales.

‘‘Control?’’

‘‘Stay!’’ replied Carlton.

‘‘TELCOM?’’

‘‘Stay!’’ replied Puddy.

‘‘GNC?’’

‘‘Stay!’’ replied Willoughby

“EECOM?”

“Stay!” replied Aaron.

“Surgeon?”

“Stay!” replied Zieglschmid.

“CapCom, we’re Stay for Tl,” Kranz directed.

“Eagle, you are Stay for Tl,’’ Duke relayed.

“Roger. Understand, Stay for Tl,’’ Armstrong acknowledged.

“Houston,” Collins called. “How do you read Columbia on high-gain?’’ Now that he was no longer optically tracking Eagle, he had manoeuvred to enable his high-gain antenna to point at Earth.

“We read you five-by, Columbia. He’s landed at Tranquility Base. Eagle is at Tranquility.”

“Yes. I heard the whole thing,’’ Collins noted. His wife was delighted that he had not been left out.

“Eagle, Houston. You are Stay for T2.’’

“Stay for T2,’’ replied Armstrong. “We thank you.’’ This decision committed Eagle to remaining on the Moon for 2 hours until Columbia came around again. Armstrong and Aldrin began to prepare for a normal liftoff, updating the guidance system to tell it that the vehicle was on the surface, in a specific orientation. This involved aligning the platform by a procedure that inferred local vertical from the gravity vector and azimuth from a star sighting. While Aldrin prepared to do this, Armstrong offered an explanation of the final phase of the descent. “Houston, that may have seemed like a very long final phase. The Auto targeting was taking us right into a football-field-sized crater with a large number of big boulders and rocks for about one or two crater diameters around it, and it required us going in P66 and flying manually over the rock field to find a reasonably good area.’’

“It was beautiful from here, Tranquility,’’ Duke replied.

Aldrin gave his initial impression of the surface, “We will get to the details of what is around here later, but it looks like a collection of just about every variety of shape, angularity, granularity, about every variety of rock you could find. The colour varies pretty much depending on how you’re looking relative to the zero phase point.[31] There doesn’t appear to be too much of a general colour at all. However, it looks as though some of the rocks and boulders, of which there are quite a few in the near area, are going to have some interesting colours to them.’’

“Be advised there’s lots of smiling faces in this room and all over the world,’’ Duke congratulated.

“Well, there are two of them up here,’’ Armstrong pointed out.

Although Columbia was below Eagle’s horizon, Houston had set up a two-way relay. But a transmission from Eagle had to go both ways to reach Collins and this imposed an extra time delay, with the result that anything that he chose to say in response to a transmission from Eagle was made almost 3 seconds late and what he said required 1.3 seconds to reach Earth, during which interval the CapCom might respond to Eagle. On hearing Armstrong’s remark, Collins immediately chipped in, “And don’t forget one in the command module’’, meaning that he was smiling too. But before this reached Earth Duke congratulated Eagle, “That was a beautiful job, you guys’’, with the result that Collins’s remark created the impression that he was reminding Earth that he had done a beautiful job too!

“Columbia, say something,’’ Duke prompted. “They ought to be able to hear you.’’ “Tranquility Base, it sure sounded great from up here,’’ Collins called. “You guys did a fantastic job.’’

“Thank you,’’ acknowledged Armstrong. “Just keep that orbiting base ready for us up there now.’’

“Will do,’’ Collins promised.

Several minutes later, Armstrong called Houston, “The guys who said that we wouldn’t be able to tell precisely where we are – they’re the winners today. We were a little busy worrying about program alarms and things like that in the part of the descent where we would normally be picking out our landing spot. Aside from a good look at several of the craters we came over in the final descent, I have not been able to pick out anything on the horizon as a reference as yet.’’

“No sweat,’’ replied Duke. “We’ll figure out.’’

Bill Anders and Ken Danneberg, a friend of the Armstrong family, launched a $1 ‘pool’ on where Eagle had set down.

The medics had expressed concern that when the astronauts ventured outside they might have to spend some time at the foot of the ladder adapting to the local gravity prior to moving off but, as had been pointed out in response, by then they would have had several hours to acclimatise by standing in the cabin. Armstrong made this point. ‘‘You might be interested to know that I don’t think we notice any difficulty at all in adapting to one-sixth g. It seems immediately natural to us to move in this environment.’’ He then reported what he could see through his window. ‘‘The area is a relatively level plain with a fairly large number of craters of the 5- to 50-foot variety, some ridges 20 to 30 feet high, I’d guess, and literally thousands of 1- and 2- foot craters. We see some angular blocks out several hundred feet in front of us that are probably 2 feet in size. There is a hill in view, just about on the ground track ahead of us. It’s difficult to estimate, but it might be a half a mile, or a mile.’’

‘‘It sounds like it looks a lot better than it did yesterday at that very low Sun angle,’’ interjected Collins. ‘‘It looked rough as a cob then.’’

‘‘It really was rough, Mike,’’ Armstrong pointed out. ‘‘At the targeted landing area it was extremely rough with a crater and a large number of rocks that were probably larger than 5 or 10 feet in size.’’

‘‘When in doubt, land ‘long’,’’ Collins observed.

‘‘We did,’’ Armstrong agreed. Picking up his observations, he continued, ‘‘I’d say the local surface is very comparable to that we observed from orbit at this Sun angle; about 10 degrees. It’s pretty much without colour. It’s a very white, chalky grey, as you look into the zero phase; and it’s considerably darker grey, more like ashen grey

The target ellipse was 11 nautical miles long and 3 nautical miles wide, with its major axis along the intended direction of approach. Eagle came in south of track and landed at the point marked by the cross hairs. Inset: After passing over rocks north of West Crater, Eagle landed just beyond a smaller crater. (Based on S69-3716 and S69-3723)

as you look out 90 degrees to the Sun. Some of the rocks in close here that have been fractured or disturbed by the rocket engine plume are coated with this light grey on the outside; but where they’ve been broken they display a very dark grey interior – it looks like they could be country basalt.’’

While it was not necessary for mission success to determine in real-time where Eagle had landed, Collins was eager to find it by a P22 landmark tracking exercise in order to assist in the rendezvous. The sole reference was the large blocky crater that Armstrong had reported passing over. However, he had neglected to mention having later passed over a smaller crater. Nevertheless, the engineers were able to utilise tracking from the Manned Space Flight Network and telemetry from the onboard guidance systems to estimate the landing point by recreating the descent trajectory. As team member Lew Wade reflected, “All indications were that they were ‘long’, but the guidance systems didn’t agree: PGNS put them a bit north of the planned site; AGS put them in the middle. The first Manned Space Flight Network report had them to the south.’’ The various estimates were marked on a large-scale map of the ellipse, and all were within a 5-mile radius, with most clustered downrange of the big crater. Meanwhile, Gene Shoemaker’s team of geologists, working in a science support room, evaluated the crew’s descriptions of their surroundings (in particular that they were on ‘‘a relatively level plain with a fairly large number of craters’’) and reasoned that, as intended, Eagle had flown down the major axis of the ellipse; for some reason had come in ‘long’; and Armstrong had ‘extended’ in order to avoid a blocky crater. Of two candidates for this crater, one was rejected, which left one. To cut a long story short, the issue would not be resolved until the 16-millimetre Maurer film of the powered descent was studied after the mission, whereupon it was realised that Shoemaker’s team had identified the site to within 200 metres.

‘‘We cannot see any stars out the window,’’ Armstrong noted, ‘‘but out of my overhead window I’m looking at the Earth; it’s big and bright and beautiful.’’ At this point, Aldrin was preparing to take the star sighting for platform alignment. ‘‘Buzz is going to give a try at seeing some stars through the optics.’’

‘‘Columbia, Houston,’’ Duke called. ‘‘It’s coming up on 2 minutes to LOS, and you’re looking great going ‘over the hill’.’’

While Collins passed around the far side of the Moon, Armstrong and Aldrin proceeded with their activities more or less independently of Houston. As soon as Collins reappeared around the eastern limb on revolution 15, Duke gave him one estimate of the landing site, which was ‘‘about 4 miles downrange’’. He provided selenographical coordinates, which Collins entered into his computer.

‘‘Tranquility Base. Houston,’’ Duke called. ‘‘You are Stay for T3.’’

‘‘Roger.’’ Armstrong acknowledged. This terminated the preparations for a lift off, and enabled Eagle to be powered down.

On concluding his momentous shift, Kranz shook Tindall’s hand, found Koos to thank him for throwing the 12-01 program alarm into the final simulation, and then he accompanied Douglas Ward, his Public Affairs Officer, across the road to the News Center.