Apollo 14 TV Cable Pulls

Apollo 14 TV Cable Pulls

Last revised 15 April 2007.

At about 135:24:38, late in the Apollo 14 EVA-2 close-out, Ed Mitchell was about to head up the ladder. Al Shepard was walking toward the ladder from the MESA with the rockbox, which he would hand to Ed once Ed was up on one of the lower rungs and had had a chance to stomp his boots to clean some of the dust off his legs. As Al moved toward the ladder, his foot caught under the TV cable and pulled it enough that the camera tipped forward and fell to the ground. As indicated below, this was at least the fifth instance during the close-out that the camera moved as a result of Al snagging the TV cable with his boot. An analysis of this sequence of cable tugs suggests that, cumulatively, they put the camera and cable in a much more vulnerable configuration than would have otherwise been the case.

Before detailing specific instances camera motions due to cable snags, let us consider the configuration of the camera and its cable.

Figure 1 is a detail from the 4 o'clock Hasselblad pan Al took early in the first EVA soon after 114:53:34. It shows Ed taking a TV pan.

Fig. 1. Ed Mitchell with the color TV camera. Detail from AS14-66-9241.

As can be seen in the figure, the TV cable was attached to the back of the camera and was hanging more or less straight down, with a bulky cable connector about halfway down. There are some loops of cable draped on the tripod legs; and, from there, the cable can be followed out of the field-of-view to the left toward the MESA. As indicated by the loops of cable, Al did not deploy the camera as far from the LM as the cable would have allowed. A comparison of the Hasselblad pan images, the TV record, and AS14-66-9341, a photo Ed took out is window after EVA-2 indicate that, other than some minor repositioning during re-aiming, the crew did not move the camera away from the spot where Al deployed it early in EVA-1.

detail from 9341 showing the TV configuration after EVA-2

Fig. 2. TV location after EVA-2. Detail from AS14-66-9341.

The fact that there was loops of cable at the camera when it was deployed means that unintentional cable pulls would not have resulted in camera motion unless (1) the loops caught on the tripod legs and moved them or (2) enough cable was cumulatively dragged toward the LM in successive pulls that the excess was taken up and that the cable ended up in a configuration something like that indicated in Figure 3.

detail from 9241 showing the TV configuration after EVA-2

Fig. 3. Conjectural configuration of the TV cable
after all the excess cable had been tugged toward the MESA.
Adapted from AS14-66-9241.

In instances where the cable caught on the tripod legs, the legs would necessarily move at least a little toward the LM and the camera would tend to rock back. That would result in the fixed objects in the field-of-view - such as the tip of the S-band antenna - appearing to move down. In instances where the cable was free of the legs with little or no excess cable between the MESA and the camera, a cable pull would tend to pull the camera toward the spacecraft, causing it to rock forward over the tripod legs. Fixed objects would appear to move up in the TV view. In either case, some sideways motions in the TV image might also occur, depending on the orientation of the tripod legs.

The cable pulls and camera motions discussed here all occurred after about 135:01:56 when Al aimed the TV at the MESA so Houston could watch the close-out. A review of the available recordings show camera motions large enough to disturb the recorded image occuring at about 135:16:34, 135:19:06, 135:22:20, 135:22:56, and 135:24:38. Not surprisingly, at the time of each of these camera motions Al was moving away from the camera. Probably because Ed did almost all of his work on the ladder side of the MESA and MET, he doesn't not appear to have snagged the TV cable during this part of the mission. The MET is near the MESA but a few meters closer to the camera. In the TV view, the cable passes the MET on the left.

First Camera Motion

135:16:26 Mitchell: (At the MET, on the right) We didn't get anything in that magnetic sample container, did we?

135:16:29 Shepard: (At the MET, on the left) No, we did not. TDS stuff's up there.

135:16:33 Mitchell: I've got it.

135:16:34 Shepard: Good.

[Al and Ed both go to the MESA, Al on the left and Ed on the right. Al catches the TV cable with his boot and the camera moves slightly. The first motion is image-down. Because Al was moving away from the TV, he reduced the amount of slack, possibly pulling one or more loops toward the LM and, presumably, over the tripod legs, causing the camera to rock backwards slightly. No cable motion is visible in the rather grainy TV recording.]

135:16:39 Mitchell: Your feet are about to get tangled up in the TV cable again. Don't fall.

135:16:43 Shepard: Okay. (Long Pause)

Second Camera Motion

[In this part of the TV recording, the cable can be seen faintly, running from the MESA to the lower left corner of the TV image, passing to the left of the MET and to the right of the S-band antenna.]

135:18:41 Mitchell: (At the MESA on the right) All right. We need the Plus Z-27 bag, right?

135:18:46 Shepard: (At the MET on the left) Yeah. Either that, or else put that in the weigh bag, and take this up with it. 135:18:56 Mitchell: Okay, I'm getting you a bag for it (out of the MESA).

135:18:58 Shepard: Okay, we'll use that one, then. Here's your two weigh bags that go in the ETB. (Going to the MESA on the left) How are you fixed for (garbled), there?

[While moving toward the MESA, Al catches the TV cable again. There is a small, initial, image-down motion of the TV image; but then a much larger image-up motion. The first motion is presumably the result of of a loop catching on the tripod. Immediately after this first motion, the TV cable can be seen moving in a whip like motion, clearly under some tension, relatively taut, and off the ground in the near field. At the end of this incident, the cable probably ends up in a configuration somewhat like that suggeted in Figure 3, above.]

Cable Snag without any Camera Motion

135:20:42 Mitchell: (At the MESA on the right) Houston, how much time do we have left?

135:20:47 Haise: Stand by, Ed. (Pause)

135:20:58 Shepard: (Going to the MESA on the left) That do it...

135:20:59 Haise: Okay...

135:20:59 Shepard: (Garbled under Haise).

135:21:01 Mitchell: (Garbled under Haise)

135:21:01 Haise: ...we've got about 18 minutes, now (to cabin repress).

135:21:05 Mitchell: Oh, we've got lots of time. Okay. (To Al, who has turned toward the MET) Watch your feet again.

[Al has already realized that he's caught the cable and raises his right boot to free it.]

135:21:09 Shepard: Yeah, I'm watching them. Okay. (Looking at his checklist) You have the...(The) ETB's stowed, right?

Third Camera Motions

135:22:07 Mitchell: (At the MESA on the right) Yup. (Pause) Yes, Fred. It's in the ETB, now.

135:22:19 Haise: Okay, and did...

135:22:21 Shepard: (Joining Ed at the MESA) Okay. We'll just have these three weigh bags, then.

[As Al moves to the MESA, he catches the cable and pulls it enough that it jumps off the ground in a whipping motion, which flips the cable connector into the TV field-of-view. There is quite obviously very little slack remaining. The first image motion is of large amplitude and image-up.]
[In February 2007, Journal Contributor Harald Kucharek called attention to an object that appeared briefly at the lower left in the TV image at this point. Its appearance was so brief that the effects of the color-wheel technology can be seen in the image. Ken Glover produced a video clip ( 4.8 Mb ) showing the event in real time and then at 1/32 actual speed.]
[Over a twenty-four hour period following the alert from Kucharek , a group of Journal contributors - Kucharek, Ron Wells, Colin Mackellar, and Karl Dodenhoff, Eric Jones, and Ken Glover - had a vigorous e-mail discussion and concluded that the object was the cable connector that can be seen midway down the cable at the back of the camera in Figure 1. The lens cap was briefly considered, but the clear association of the object with the TV cable eliminated that possibility.]

Fourth Camera Motions

135:22:24 Haise: Okay, did the 100-foot tether also get into the ETB?

135:22:30 Mitchell: That's affirmative; it's there.

135:22:36 Shepard: Okay. (Both back at the MET) Okay; we'll take those along.

135:22:47 Mitchell: Yeah. How're we going to handle them?

135:22:53 Shepard: (Both back at the MESA) I'll put them in here next trip

135:22:55 Mitchell: Okay. (Pause).

[Al snags the cable again; but the result is only minor camera motion. The first motion is image-up, an indication that the cable is relatively taut. No cable motion can be seen in the recorded TV image.]

Fifth Camera Motion - The Camera Falls

135:24:05 Shepard: (Both back at the MESA) Want to head on up the ladder? I'll hand you...

135:24:08 Mitchell: Yeah.

135:24:09 Shepard: ...the SRC. I believe if you just stomp your feet on the way up, it'll be as effective as the brush was yesterday.

135:24:19 Mitchell: Okay. You're probably right.

135:24:22 Shepard: Okay.

135:24:23 Mitchell: (At the foot of the ladder) Did you...I saw you over here. Did you get a picture (of Earth)?

135:24:26 Shepard: I did. Of the LM in the foreground?

135:24:30 Mitchell: Yeah.

135:24:34 Shepard: Yep. Several.

135:24:35 Mitchell: Okay, you ready to go up?

135:24:37 Shepard: Sure!

135:24:38 Mitchell: All right, Fredo, I'm starting up the ladder.

135:24:40 Haise: Roger, Ed.

[Al heads toward the ladder from the MESA. He catches the TV cable and finally pulls it hard enough to pull the camera far enough forward over the tripod base that it falls to the ground, apparently without damage.]

135:24:46 Mitchell: (Stomping his boots on the ladder) How's that doing?

135:24:47 Shepard: That's good. Shaking the heck out of the LM.

135:24:51 Mitchell: Huh?

135:24:52 Haise: Okay...

135:24:53 LM Crew: (Garbled)

135:24:53 Haise: ...someone must have got caught in the cable; we just saw the TV go over.

135:25:02 Shepard: Well, we finally did it to you; sorry.

[After handing Ed the rockbox, Al goes to the TV camera, sets it on its feet, brushes the lens, and leaves it in the configuration shown in Figure 2 (above).]

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