# How did Apollo-12 manage to land next to Surveyor-3? First “Space-Tourists”?

To me this looks like the first instance of space-tourism (humor, pls don't add the tag, see exemplary documentation at end of question). The astronauts landed next to Surveyor-3 on purpose, got out of their spacecraft, walked over to it, took pictures of each other next to it, collected a couple of souvenirs (for later study), packed up, got back in their spacecraft, and went home. OK they did do a lot of other things while there as well.

How did they know the location of Surveyor-3 with such precision, using 1960's technology? There was precious little extra fuel on the lander to fly around and look for it, so they must have had a pretty good idea how to navigate there and safely land within walking distance (~200m). How was Surveyor-3's location known to such accuracy?

below: From here.

Charles Conrad Jr., Apollo 12 Commander, examines the unmanned Surveyor III spacecraft during the second extravehicular activity (EVA-2). The Lunar Module (LM) "Intrepid" is in the right background. This picture was taken by astronaut Alan L. Bean, Lunar Module pilot. The "Intrepid" landed on the Moon's Ocean of Storms only 600 feet from Surveyor III. The television camera and several other components were taken from Surveyor III and brought back to earth for scientific analysis. Surveyor III soft-landed on the Moon on April 19, 1967.

below: Surveyor-3, cropped copy of From here.

NASA Image ID number: AS12-H-48-7121, NASA

Apollo 12 astronaut Alan Bean took this picture of the Surveyor 3 spacecraft on the second moonwalk EVA on 20 November 1969. Surveyor 3 landed on the Moon inside the edge of a small crater on 20 April 1967 where it took pictures and transmitted them back to Earth and performed soil mechanics experiments. The arm of the soil mechanics sampler is seen extended out to the right. The panels on top of the center mast are the solar arrays. The camera is the white cylinder just to the right of the mast. The arm extending upward to the left is the omnidirectional antenna. The spacecraft is just over 3 meters high. This view is looking to the north.

below: Examples of getting out of a transporting craft, walking over to it, taking a picture with it, and (presumably) packing up, getting back into the craft and going home, presumably having done other things as well.

• Brought some parts of Surveyor back too. – Organic Marble Feb 25 '17 at 2:18
• I thought those parts were "souvenirs" :) Real space tourism – Fred Feb 25 '17 at 7:33
• Those parts were retrieved so they could be examined for the effects of long-term exposure to space. – Hobbes Feb 26 '17 at 11:50
• @Fred very good point - I've linked to your comment in the question. – uhoh Feb 27 '17 at 1:03
• @Hobbes thanks for pointing this out - I've linked to your comment in the question and asked a follow-up question. – uhoh Feb 27 '17 at 1:16

"How was Surveyor-3's location known to such accuracy?"

The Surveyors were located using Lunar Orbiter photography (not necessarily of the probe themselves, just the surrounding area).

These coordinates were obtained by determining the position of the landed Surveyors on Lunar Orbiter photographs by matching features shown in Surveyor pictures with corresponding features in the Lunar Orbiter photographs (refs. 1-2, 1-4, 1-5, and 1-19 (see ch. 3)). The Lunar Orbiter photographs were, in turn, related to the Orthographic Atlas and Mills/Arthur coordinates by matching large features, visible from Earth.

All were locateable in this way except for Surveyor V. Surveyor I was actually photographed on the surface itself by a Lunar Orbiter.

From Surveyor Program Results, NASA SP-184, page 8.

There is more detail in the chapter Location of the Surveyor Spacecraft (page 36):

The landed location of the Surveyor III spacecraft was pinpointed (ref. 3-14) on Lunar Orbiter IV photograph H - 125, as were the following eight measured points : Mills 308, Gambart R , Fra Mauro B , Saunder 233 , Lansberg beta, Euclides K , Arthur 3402511 , and Lansberg N. Adopting a similar procedure to that used for Surveyor I , the following coordinates were determined for Surveyor III:

1. 34° W ± 0.01°, 2.97° S ± 0.01°

On. the Saunder-Franz system , these would be

23.34° W, 2.99° S.

• Remote television observations on the moon! 3-14. Shoemaker, E. M.; Batson, R. M.; Holt, Il, E.; Morris, E. C., Rennilson, J. J. and Whitaker, E. A.: Television Observations from Surveyor III. J. Geophys. Res., vol. 73, no 12, June 15, 1968, pp. 3980-4043. Now to get that paper and find photograph H-125 from Surveyor-4. This is good stuff, thanks! – uhoh Feb 25 '17 at 2:59
• Near the equator, one degree of lunar circumference is about 30km, so the Surveyor coords were known ± 300m. – Russell Borogove Feb 25 '17 at 18:55
• To double check that I understand; television imagery received on Earth from the lander was matched to later television imagery received on Earth from the orbiter. After all of that, a map was generated for the Apollo-12 astronauts, instructing them to "keep an eye out for the snowman" and land on his belly-button? – uhoh Feb 27 '17 at 0:56
• Yes, the linked reference goes into a lot of detail on the process in the "Location of the Surveyor Spacecraft" chapter, "Location of Surveyor 1" subheading. However, it seems that the Lunar Orbiters might have come after the landings, not before. There is a quote "The problem was not finally solved until the general area was photographed in both medium and high resolution by Lunar Orbiter". They used 13 landmarks from the overhead imagery, matched them with TV images, and drew a location grid (which is shown in the document). As a bonus, Surveyor 1 also was visible in the photos :) – Organic Marble Feb 27 '17 at 2:08
• Dates: Surveyor 1 landing: June 2 1966 / Lunar Orbiter 1: Imaged Moon: August 18 to 29, 1966. Man, NASA had a lot of irons in the fire in that decade! – Organic Marble Feb 27 '17 at 2:12

On the landing approach, Conrad saw and identified "Surveyor crater" very quickly after the "pitchover" maneuver that allowed a surface view out the windows of the LM. This was a 400-foot wide crater inside which Surveyor III was known to be. The crew had trained with both photos and models of the terrain built from Lunar Orbiter imagery, so knew what to look for.

Here are some excerpts from the annotated transcripts; square brackets are official annotations, curly brackets mine:

110:29:03 Conrad: I'm trying to cheat and look out there. I think I see my crater.

110:29:08 Bean: (Garbled)

[Pete is leaning forward, pressing his helmet against the window in an attempt to see the landing site. Figure 4-9 from the Mission Report shows a portion of a view Pete might have had in the LM simulator.]

[Head Crater is the large crater just below the top of the image. Surveyor Crater, which is 'his crater', is the larger crater below Head Crater. The bottom left image shows the view at pitchover as seen by the 16-mm camera mounted in Al's window. The sketch at bottom right includes an outline of the Snowman. {the center of which is Surveyor Crater}]

110:29:10 Bean: Coming through 7 (thousand feet). (Garbled) P64. P64, Pete. (Garbled)

110:29:14 Bean: Pitching over

110:29:15 Conrad: That's it; there's LPD.

[In the Landing Point Designator mode of operation, Pete can use his handcontroller to re-target the LM. If he wants to redesignate the target, he clicks the handcontroller left or right, forward or back to get a small change; or he gives several clicks to get a big change.]

110:29:17 Carr {CAPCOM}: Roger. Copy P64.

110:29:18 Bean: Okay, there's 6000 update.

110:29:20 Conrad: (Very excited) Hey, there it is! There it is! Son-of-a-Gun! Right down the middle of the road!!!

110:29:25 Bean: Outstanding! 42 degrees, Pete.

110:29:27 Conrad: Hey, it's targeted right...

110:29:28 Bean: 42.

110:29:28 Conrad: ...for the center of the crater!

According to Digital Apollo, the initial, automatically selected landing target would have been about 600 feet to the southwest of Surveyor itself if Conrad had let the P65 automatic landing program have its way. Apparently he didn't like the look of the terrain there, so made a number of landing point redesignations under the automatic system, before taking over manual control at about 400 feet altitude. He wound up touching down about 600 feet WNW of Surveyor.

So Conrad wasn't flying around looking for the probe so much as looking for a good parking spot -- he could see he was in basically the right place.

• Digital Apollo is a really excellent book on the role of human-computer interaction in the project, focusing especially on the LM landing software. Link added. – Russell Borogove Feb 25 '17 at 6:21
• Among other things, it has just about the best explanation of Apollo 11's 1201/1202 program alarms that I've read. – Russell Borogove Feb 25 '17 at 6:22
• Yes, that's a fine book indeed. – Organic Marble Feb 25 '17 at 18:37
• Is... is the "snowman" in fig. 4-9c real? – Nic Hartley Feb 25 '17 at 20:44
• The "snowman" is a group of 6-7 craters. The outline has been added to the drawing in 4-9c to make it clear what constitutes the "snowman", but there's no lunar terrain corresponding to the outline itself. Think of it as similar to drawings of constellations showing how a handful of stars can be interpreted as a bear. – Russell Borogove Feb 25 '17 at 21:15

The Lunar coordinates of the landing site were 3.01239° S latitude, 23.42157° W longitude which Ewen Adair Whitaker ( who had previously successfully located Surveyor 1 for NASA) designated as 1,180 feet (360 m) from the location of Surveyor 3, a distance that was chosen to eliminate the possibility of lunar dust being kicked up by Intrepid's descent engine during landing. The actual touchdown point was approximately 600 feet (183 m) from Surveyor (Conrad actually landed Intrepid 580 feet (177 m) short because it looked rougher during final approach than anticipated) did cause high velocity sandblasting of the probe. It was later determined that the sandblasting removed more dust than it delivered onto the Surveyor, because the probe was covered by a thin layer that gave it a tan hue as observed by the astronauts, and every portion of the surface exposed to the direct sandblasting was lightened back toward the original white color through the removal of lunar dust –The landing site would thereafter be listed as Statio Cognitum ( a "known anchorage" vital to all navigators) on lunar maps. The story of the role played by Dr,Gerad Kuiper's Team at the Lunar and Planetary Lab in Tucson, Arizona is superbly documented here:-http://www.desertmoonfilm.com/

• lovely additional information, but not an answer to the question. – JCRM Mar 15 '18 at 6:19
• The question is "how did they know the location of Surveyor with such precision". This doesn't answer that. – Organic Marble Mar 15 '18 at 14:29
• Ewen Adair Whitaker FRAS (1922-2016) had previously located Surveyor 1 for NASA so they recruited the Lunar & Planetary Lab (Tucson) to locate Surveyor 3 ( “A Pinpoint on the Ocean of Storms: Finding the Target for Apollo 12”).After the near crash landing of Apollo 11 the primary purpose of the Apollo 12 mission was to demonstrate a pinpoint landing capability so NASA designated the coordinates of Surveyor 3's "known location". In fact Conrad landed Intrepid 580 feet (177 m) short only approximately 600 feet (183 m) from Surveyor 3 (not 1,180 feet ,360 m as anticipated)-Ewen Whitaker was how. – A. De Salle Mar 17 '18 at 7:03

Ewen Whitaker FRAS (1922-2016) was a member of Lunar Surveyor TV Investigator Team and located landed positions of four Surveyors, including Surveyor 3.He was also aMember of Lunar Orbiter V Scientific Site Selection Team (choosing 4 of the final list of sites).Having bounced 2X on landing (April 20 1967) Surveyor 3 shut down on it's 1st lunar nightfall & at the next lunar dawn (14 terrestrial days) it couldn't be reactivated.It's TV camera returned 6315 pictures.Thorough analysis of these photos combined with images /selenodetic, radiation intensity, and micrometeoroid impact data from the Lunar Orbiters enabled to precisely locate the Surveyor probe.I do hope that answers the question and if anyone is genuinely interested in the subject might I again recommend the documentary - http://www.desertmoonfilm.com/

• instead of adding a second answer, you can edit your initial one to improve it. – Hobbes Mar 17 '18 at 8:35
• Stack Exchange Question and Answer posts can be edited forever. No need to post a new one each time there is something to add. The editing triggers a "new activity" flag and the post becomes visible again, so people will be aware of the edit. – uhoh Mar 17 '18 at 13:32