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Apollo 17: The Blue Marble

"The Blue Marble" is one of the most widely distributed photographic images in existence, but NASA says the identity of the photographer is unverifiable. I decided to take that as a personal challenge.

Original NASA Caption, Saturday December 23, 1972:
View of the Earth as seen by the Apollo 17 crew traveling toward the moon. This translunar coast photograph  extends from the Mediterranean Sea area to the Antarctica south polar ice cap. This is the first time the Apollo trajectory made it possible to photograph the south polar ice cap. Note the heavy cloud cover in the southern hemisphere. Almost the entire coastline of Africa is clearly visible. The Arabian Peninsula can be seen at the northeastern edge of Africa. The large island off the coast of Africa is the Malagasy Republic. The Asian mainland is on the horizon toward the northeast. 
 

Earth is said to have the appearance of a child's marble in the photo; that is the Earth has the same aspect at this distance as a child's marble at about arm's length. NASA officially credits the image to the entire Apollo 17 crew Eugene Cernan, Ronald Evans and Jack Schmitt all of whom took photographic images with the on-board Hasselblad. Schmitt later claimed that he personally took the famous image, but the identity of the photographer is unverifiable.
     -- from Wikipedia entry for "The Blue Marble" as of March 22, 2006

   

By Eric Hartwell - Last updated Wednesday April 25, 2007

When I started this project, I expected to prove that the "Blue Marble" photo was taken by Jack Schmitt as commonly accepted. More than a year later, the answer is still up in the air. I've established almost everything else:

  • The photo was taken on December 7, 1972, between 4:59:05 and 5:08:14 after launch.
     
  • The spacecraft was aimed towards the earth at an attitude of 274 roll, 164 pitch, 0 yaw using the Launch Pad REFSMMAT.
     
  • As Murphy's Law predicts, this was the only time during the mission when all three astronauts used the same camera:
     
    • Ron Evans took some Earth pictures at 4:47, then handed the camera to Gene Cernan.
       
    • Gene took  a series of photos of the S-IVB 3rd stage ending around 5:00 after launch, then handed the camera to either Ron or Jack Schmitt.
       
    • Ron or Jack (and most probably not Gene) took "the" blue marble photo (actually a series of 4) between 4:59:05 and 5:08:14.
       
  • The Apollo 17 flight transcripts are incomplete and contradictory
     
  • Jack took most of the Earth photos on the outbound trip:
    •  five dozen while in Earth orbit.
    • 5 more during the translunar burn, including spectacular views of the sunrise.
    • another 8 during docking
    • another 30 on the coast to the moon, following "the" photo
       
  • The original NASA photo release gave credit to the entire crew. The crew took credit for that picture as a whole, or would jokingly each take credit for it in turn.
     
  • Apollo 17 tested two new food types - irradiated ham and a nutritional fruitcake (see recipe).

"Did you get any pictures of that?"

NASA released the photo on Saturday December 23, 1972, one of eight photos in the second batch released. It made the front page of most newspapers over the Christmas weekend. Who gets the credit?

Credit, Crew:
The original NASA photo release gave credit to the entire crew.
 
No, Jack:
A UPI wire story released on Saturday December 23, 1972 credited Schmitt, apparently based on the reporter's interpretation of the ground-to-earth communications from December 7.
 
No, Crew:
The UPI caption for the wire photo released on Saturday December 23, 1972 credited the crew. The AP caption and AP stories credited the crew.
 
No, Crew:
"The crew accept credit for that picture as a whole. I've actually been to events where all three of them kind of jokingly take credit for it. And we've never really been able to quite pin down which one of the crewmen, Cernan, Evans or Schmitt took the picture. ... No one at that time in our photo lab had any idea I think of how long lasting it would be..." -- Mike Gentry, NASA Media Resource Centre, 1999 [ref]
 
No, Ron:
Early in the mission, Astronaut Ron Evans made his most notable photographic contribution; he took a picture that will rank among the classics of the space program. As Apollo sped toward the moon after blasting into its translunar trajectory, he pointed his camera back toward home and caught a stunning view of the earth, with the side visible to the astronauts completely illuminated. -- Portfolio from Apollo -- Time Magazine -- Monday, January 8, 1973
 
No, Gene:
"I've actually been to events where all three of them kind of jokingly take credit for it." -- Mike Gentry, again
 
No, Jack:
"I've actually been to events where all three of them kind of jokingly take credit for it." -- Mike Gentry, again

Who's on First

The Detailed Timeline shows that the "Blue Marble" photo was taken between 5:00 and 5:08 after launch. The Apollo spacecraft was facing back towards the Earth, and the astronauts were still in their space suits.

The time of Apollo 17's launch, 12:33 a.m. EST, meant that Africa was in daylight, and with the December solstice approaching, Antarctica was also illuminated.

The photograph was taken at a distance of about 45,000 kilometers, about 1 hour 48 minutes after the spacecraft left Earth orbit on its way to the Moon, and about 5 hours 6 minutes after launch. The spacecraft's trajectory aligned it with the Earth and Sun, providing a view of an almost completely full Earth.

Command Module Pilot (CMP) Ronald Evans was in the left-hand seat. After docking with the Lunar Module (LM) and extracting it from the S-IVB, Evans initiated a separation maneuver, then pitched the CSM/LM stack down so that the S-IVB was clearly visible through the center, hatch window.

Commander (CDR) Eugene Cernan was in the center seat. After  the Command and Service Module (CSM) docked with the LM, Cernan went down into the short tunnel leading to the lander, opened the hatch cover,  and verified the latches holding the two spacecraft together. He connected electrical umbilical cables, reinstalled the hatch, then returned to his seat to observe the S-IVB.

Lunar Module Pilot (LMP) Jack Schmitt  was in the right-hand seat, observing, photographing, then monitoring the LM. During this part of the flight Schmitt managed communications and the flight plan checklist and updates.

The astronauts were waiting to watch the S-IVB as it fired its engines to send it into a controlled crash on the Moon.

"We'd like to confirm, from the crew of America, that the world is round."

All three astronauts took photos during this period.

The spacecraft was facing back towards the Earth, pitched down so that the S-IVB was clearly visible through the Command Module's hatch window.

I've determined the actual orientation of the S-IVB/LM relative to the Earth by pasting together the 16 mm movie frames from the pitch maneuver. Since the pitch maneuver was performed at a constant rate, it's possible to measure the angles directly from the combined image. The center of the Earth was 70 down from the CSM / S-IVB/LM axis.

The Earth was visible through the side windows, 1 and 5, but probably blocked by the LM through the other windows. This narrows the possibilities down to Evans or Schmitt ... or, possibly Cernan. Oops.

After separation and pitch down, Evans took some photos of the Earth. [004:47] "Okay. POWER's OFF. Hey, Jack. Hand me the Hasselblad. I think we're bowing the right direction. Yes, the Moon is there. The Earth is - that's the Earth. ... The Earth just fills up window 5. Okay, f infinity, about a 250th."

He then passed the camera to Cernan, who photographed the S-IVB: "Let's get a picture or two here yet, and we'll give you a GO.... [004:56] ... And for your reference, at frame 105 I started a few 250-millimeter pictures of the S-IVB".

After they switched to the 80mm lens some time between 5:00 and 5:03 GET, first photo was of the S-IVB (22724), and the second was of the Earth (22725). The next three photos (22726-7-8) were the "Blue Marble".

Murphy's law steps in. January 16, 2006: there are critical disagreements between the PAO Mission Commentary Transcript and the Technical Air-to-Ground Voice Transcription, and the Onboard Voice Transcription is missing the entire period from 1:27 to 35:30. I'm now pursuing the original transcript and/or tapes. - Eric

-- PAO --
SC
Okay, you have a GO. And for your reference, it's frame 105, I started a few 250 millimeter pictures of the S-IVB.
CC Roger, Gene.

-- TECHNICAL --
CDR
Okay. You have a GO.
LMP And for your reference, at frame 105 I started a few 250-millimeter pictures of the S-IVB.
CC Roger, Jack.

My theory (and what it is, too)

There's a more detailed analysis in the Overview section. I've prepared a separate Detailed Timeline combining the flight plan, capsule communications transcript, and photos, and a Geometry section discussing who and what was where, and the view from each window. I've also collected information about the Cameras and Photos, and posted a copy of the Image Catalog for the Apollo 17 photos from Earth orbit to the moon.

Here's my reconstruction of the actual events:

March 22, 2006: I still believe Schmitt took the picture, but I still don't have a definitive transcript, so we still don't know for sure who said what. Still working on it, still. - Eric

004:59  Cernan: "I know we're not the first to discover this - but we'd like to confirm, from the crew of America, that the world is round."
CapCom: "Roger. That's a good data point."

  AS17-148-22717
#110 AS17-148-22717
AS17-148-22718
#111 AS17-148-22718
  AS17-148-22719
#112 AS17-148-22719
AS17-148-22720
#113 AS17-148-22720
  AS17-148-22721
#114 AS17-148-22721
AS17-148-22722
#115 AS17-148-22722
  AS17-148-22723
#116 AS17-148-22723
AS17-148-22724
#117 AS17-148-22724
  AS17-148-22725
#118 AS17-148-22725
AS17-148-22726
#119 AS17-148-22726
  AS17-148-22727
#120 AS17-148-22727
 
AS17-148-22728
#121 AS17-148-22728
 

CapCom: "Have you gotten a good look at any of that weather down there on the Antarctic?"
Cernan: "Well, Ron's at window number 1 - maybe he can tell you a little about it."
Evans: "You know, it's real funny there in Antarctica the - You can see the snow, but there isn't any weather at all in it. All of the weather's around it in the water."
Schmitt: "That's where the moisture is."
Schmitt?Evans? "I don't know what to take a picture of."

  • Both Evans and Schmitt are looking at the Earth through their side windows. Schmitt takes a series of Earth photos (#110 AS17-148-22717 through #115 AS17-148-22722) with varying exposures, using the telephoto lens.

...

005:02: Cernan?Schmitt? "No, I'll change lens now."

  • They change the lens from 250mm telephoto to 80mm normal in preparation for the S-IVB burn. While changing the lens, they bump the shutter causing the blank frame (#118, AS17-148-22724). Cernan takes the photo of the S-IVB (#118, AS17-148-22724) through the hatch window.

Cernan?Evans? "Okay. Here Jack, can you see it good?"
Schmitt?Evans?Cernan? "Check the lens[settings] now. I took an F-22 stop."

  1. Cernan: "Okay. Here Jack, can you see it good?"
    Schmitt: "Check the lens[settings] now. I took an F-22 stop."
    • Cernan passes the camera to Schmitt so he can photograph the whole Earth with the normal lens. Schmitt takes the first picture (frame #119, AS17-148-22725) then remembers to change the f-stop to compensate for the brightness of the Earth. Schmitt then takes three more photos, with slightly different aim because there's no viewfinder and he wants to make sure to get the whole planet in the picture. These photos are the famous "Blue Marble".
    • Schmitt passes the camera back to Cernan for pictures of the S-IVB burn through the hatch window. Schmitt reminds Cernan he changed the lens setting.
       
  2. Cernan: "Okay. Here Jack, can you see it good?"
    Cernam: "Check the lens[settings] now. I took an F-22 stop."
    • Cernan passes the camera to Schmitt so he can photograph the whole Earth with the normal lens. Schmitt takes the first picture (frame #119, AS17-148-22725) then Cernan reminds him to change the f-stop to compensate for the brightness of the Earth. Schmitt then takes three more photos, with slightly different aim because there's no viewfinder and he wants to make sure to get the whole planet in the picture. These photos are  the famous "Blue Marble".

Cernan: "There it goes, Bob."
Schmitt? "There it goes, finally."

  • S-IVB evasive burn starts (no photo)

Schmitt? "It's going to be gone, I think, before we -"
Evans? "Houston, Magazine, November, November is on about 123 right now."

  • Cernan didn't get a photo of the S-IVB through the hatch window. He passes the camera to Evans so he can take a parting shot through window 1, but it's too late.
  • Evans reports the frame count. [Note: Frame count is +-1 due to the analog frame counter] .

Portfolio from Apollo

Time Magazine gave Evans credit for the photo in an article discussing the mission's photography, published 3 weeks after landing:

Early in the mission, Astronaut Ron Evans made his most notable photographic contribution; he took a picture that will rank among the classics of the space program. As Apollo sped toward the moon after blasting into its translunar trajectory, he pointed his camera back toward home and caught a stunning view of the earth, with the side visible to the astronauts completely illuminated. In crystal-clear detail it shows almost the entire coastline of Africa and the offshore island republic of Malagasy, the Arabian peninsula and an unusually thick cover of swirling clouds over Antarctica and the surrounding region at the bottom of the world.

Portfolio from Apollo -- Time Magazine -- Monday, January 8, 1973

No source is given for this statement; while it may have been based on an interview with the astronauts, there's no proof. As we shall see, according to the geometry, the timeline, and the transcripts, it could have been either Evans or Schmitt.

Testing the Theory: Need Input. More Input.

Of course, this is speculation based on contradictory, circumstantial evidence. NASA's policy is to credit photos to the entire crew unless there's only one person who could have possibly taken it. The astronauts were very busy at the time the picture was taken, observing the S-IVB and the Earth, and passing the camera back and forth, so it could have been any of them.

There are a number of things we can do to refine or disprove this theory:

  • Get a copy of the original audio tape to verify the transcript, identify the speakers, and narrow down the actual times
    March update: Waiting on NASA archives
  • See if there's movie footage that can help narrow the timeline
    March update: The 16mm film of the S-IVB firing doesn't add much. It appears the camera was handheld, and after the burn, the camera was turned on again for a few frames of the "Blue Marble".
  • Try to run an accurate simulation of Apollo 17's TD&E using Orbiter to establish the actual fields of view from windows 3 and 5.
    March update: Orbiter is a serious simulator, and I'm still learning how to use it.
  • Ask Cernan and Schmitt to comment
  • Ask other commanders and LM pilots to comment

References

Revision History

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